State of New Hampshire v. Exxon Mobil Corporation & a. ( 2015 )


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    THE SUPREME COURT OF NEW HAMPSHIRE
    ___________________________
    Merrimack
    Nos. 2013-0591
    2013-0668
    THE STATE OF NEW HAMPSHIRE
    v.
    EXXON MOBIL CORPORATION & a.
    Argued: May 21, 2015
    Opinion Issued: October 2, 2015
    Joseph A. Foster, attorney general (K. Allen Brooks, senior assistant
    attorney general, on the brief and orally), Kellogg, Huber, Hansen, Todd, Evans
    & Figel, P.L.L.C., of Washington, D.C. (David C. Frederick and Brendan J.
    Crimmins on the brief, and Mr. Frederick orally), and Pawa Law Group, P.C., of
    Newton Centre, Massachusetts (Matthew F. Pawa and Benjamin A. Krass on
    the brief).
    McLane, Graf, Raulerson & Middleton, Professional Association, of
    Manchester (Bruce W. Felmly and Patrick H. Taylor on the brief), Bancroft
    PLLC, of Washington, D.C. (Paul D. Clement on the brief and orally), and Weil,
    Gotshal & Manges LLP, of New York, New York (Theodore E. Tsekerides on the
    brief), for the defendants.
    Skadden, Arps, Slate, Meagher & Flom LLP, of Boston, Massachusetts
    and Washington, D.C. (Matthew J. Matule, John H. Beisner, and Geoffrey M.
    Wyatt on the brief), for the Chamber of Commerce of the United States of
    America, as amicus curiae.
    DALIANIS, C.J. The defendants, Exxon Mobil Corporation and
    ExxonMobil Oil Corporation (collectively, either Exxon or ExxonMobil), appeal
    from a jury verdict awarding approximately $236 million in damages due to
    groundwater contamination to the plaintiff, the State of New Hampshire, after a
    trial in Superior Court (Fauver, J.). The State cross-appeals from the trial
    court’s order imposing a trust upon approximately $195 million of the damages
    award. We affirm the trial court’s rulings on the merits and reverse its
    imposition of a trust.
    I. Background
    In 1990, Congress amended the Federal Clean Air Act to require the use
    of an “oxygenate” in gasoline in areas not meeting certain national air quality
    standards. See 
    42 U.S.C. § 7545
    (k) (Supp. 1991) (amended 2005, 2007). An
    oxygenate is a substance used to reduce gasoline emissions. See Oxygenated
    Fuels Ass’n Inc. v. Davis, 
    331 F.3d 665
    , 666 (9th Cir. 2003). The amendment
    did not mandate the use of any particular oxygenate; it simply required that
    “[t]he oxygen content of the gasoline shall equal or exceed 2.0 percent by
    weight.” 
    42 U.S.C. § 7545
    (k)(2)(B). To implement the requirement, the
    Environmental Protection Agency (EPA) launched the Reformulated Gasoline
    Program (RFG Program), which required gasoline containing an oxygenate of
    the manufacturer’s choice. See 
    40 C.F.R. § 80.46
    (g)(9)(i) (2000). Methyl
    tertiary butyl ether (MTBE) was one among several possible oxygenates. 
    Id.
    MTBE is a gasoline additive that increases the octane levels of fuels.
    Metropolitan areas with significant concentrations of ambient ozone were
    required to use reformulated gasoline. See 
    42 U.S.C. § 7545
    (k). Other areas,
    like New Hampshire, could opt in to the program to receive credit toward
    mandatory emissions reduction requirements. See 
    42 U.S.C. § 7545
    (k)(6)(A).
    New Hampshire joined the RFG Program in 1991, with respect to the
    State’s four southern-most counties, effective January 1, 1995. Between 1995
    and 2006, gasoline with MTBE was sold throughout the State. In 1997,
    employees at the New Hampshire Department of Environmental Services (DES)
    became aware that MTBE could pose increased risks to groundwater. In 1998,
    studies from Maine and California raised concerns about MTBE. In 1999, DES
    adopted regulations setting a maximum contaminant level for MTBE in
    drinking water and groundwater at 13 parts per billion (ppb).
    2
    In 2000, the EPA advised:
    MTBE is capable of traveling through soil rapidly, is very soluble in
    water . . . and is highly resistant to biodegradation . . . . MTBE
    that enters groundwater moves at nearly the same velocity as the
    groundwater itself. As a result, it often travels farther than other
    gasoline constituents, making it more likely to impact public and
    private drinking water wells. Due to its affinity for water and its
    tendency to form large contamination plumes in groundwater, and
    because MTBE is highly resistant to biodegradation and
    remediation, gasoline releases with MTBE can be substantially
    more difficult and costly to remediate than gasoline releases that
    do not contain MTBE.
    Advance Notice of Intent to Initiate Rulemaking under the Toxic Substance
    Control Act to Eliminate or Limit the Use of MTBE as a Fuel Additive in
    Gasoline, 
    65 Fed. Reg. 16094
    , 16097 (Mar. 24, 2000).
    In 2001, the Governor petitioned the EPA to allow the State to opt out of
    the RFG Program, but did not receive a reply until 2004. See Removal of the
    Reformulated Gasoline Program From Four Counties in New Hampshire, 
    69 Fed. Reg. 4903
     (Feb. 2, 2004). In 2004, the legislature enacted legislation
    banning MTBE gasoline effective in 2007. See RSA 146-G:12 (2005) (repealed
    2015). In 2005, Congress eliminated the oxygenate requirement and enacted a
    renewable fuels mandate to increase ethanol usage. See Energy Policy Act of
    2005, Pub. L. No. 109-58, §§ 1501, 1504, 
    119 Stat. 594
    , 1067, 1076 (2005).
    In 2003, New Hampshire sued several gasoline suppliers, refiners, and
    chemical manufacturers seeking damages for groundwater contamination
    allegedly caused by MTBE. Before trial, all defendants except Exxon settled
    with the State. After almost ten years of litigation, the case went to trial in
    2013 on three causes of action: negligence; strict liability — design defect; and
    strict liability — failure to warn. After an approximately three-month trial, the
    jury found in favor of the State on all of its claims. The jury rejected Exxon’s
    defenses that “in designing its MTBE gasoline, it complied with the state of the
    art”; that “the hazards posed by the use of MTBE in gasoline were obvious, or
    were known and recognized by the State”; and that Exxon “provided
    distributors with adequate warnings of the hazards of MTBE gasoline.” The
    jury also found that Exxon failed to prove that “the actions of someone other
    than the State or ExxonMobil (which were not reasonably foreseeable to
    ExxonMobil) were the sole cause of the State’s harm,” that “the State
    committed misconduct that contributed to its harm,” or that some or all of
    Exxon’s fault should be allocated to certain nonparties.
    The jury awarded total damages in the amount of $816,768,018. These
    damages included: (a) $142,120,005 for past cleanup costs; (b) $218,219,948
    3
    to assess and clean up 228 high-risk sites; (c) $305,821,030 for sampling
    drinking water wells; and (d) $150,607,035 for treating drinking water wells
    contaminated with MTBE at or above the maximum contaminant level. The
    jury found that Exxon’s market share for gasoline in New Hampshire during
    the applicable time period was 28.94%. Accordingly, the trial court entered an
    amended verdict of $236,372,644 against Exxon. The trial court subsequently
    awarded the State prejudgment interest in accordance with RSA 524:1-b
    (2007).
    On appeal, Exxon contends that: (1) the State’s suit should have been
    dismissed on the grounds of separation of powers and due process; (2) the suit
    should have been dismissed due to waiver; (3) the State’s claims are preempted
    by the 1990 amendments to the Federal Clean Air Act; (4) the State failed to
    establish that Exxon departed from the applicable standard of care; (5) Exxon
    did not have a duty to warn the State; (6) market share liability is not an
    acceptable theory of recovery; (7) the State should not have been permitted to
    rely upon aggregate statistical evidence; (8) Exxon was unfairly prejudiced in
    its ability to present evidence of fault on the part of other nonparties; (9) the
    trial court erred in deciding the State had parens patriae standing; (10) the
    State’s damages claims for future well impacts are not ripe; and (11) the trial
    court erred in awarding prejudgment interest on future costs.
    II. Separation of Powers and Due Process
    Exxon argues that the State’s suit should have been dismissed on the
    grounds of separation of powers and due process. Exxon asserts that based
    upon the State’s decision to participate in the RFG Program beginning in 1991,
    and the legislature’s failure to ban MTBE before 2007, “[t]he retroactive no-
    MTBE duty” imposed upon it “conflicts with bedrock principles of the
    separation of powers” and “due process.” Exxon also argues that the suit
    conflicts with the Oil Discharge and Disposal Cleanup Fund (ODD Fund), RSA
    ch. 146-D (Supp. 2014); see Laws 2014, 177:1 (repealing RSA chapter 146-D,
    eff. July 1 2025), and the Gasoline Remediation and Elimination of Ethers
    Fund (GREE Fund), RSA ch. 146-G (Supp. 2014); see Laws 2014, 177:3, I
    (repealing RSA chapter 146-G, excluding RSA 146-G:9, eff. July 1, 2025), Laws
    2014, 177:3, II (repealing RSA 146-G:9, eff. October 1, 2025). The State
    asserts that Exxon failed to preserve its separation of powers argument
    because the arguments it raises on appeal were not made to the trial court,
    and that Exxon fails to identify where it preserved its due process argument.
    The appealing party bears the burden of demonstrating that it
    “specifically raised the arguments articulated in [its appellate] brief before the
    trial court.” Dukette v. Brazas, 
    166 N.H. 252
    , 255 (2014). Generally, the
    failure to do so bars a party from raising such claims on appeal. N. Country
    Envtl. Servs. v. Town of Bethlehem, 
    150 N.H. 606
    , 619 (2004). But see Sup.
    Ct. R. 16-A (plain error rule). We have reviewed the record and agree with the
    4
    State that Exxon failed to preserve its separation of powers argument
    concerning the State’s purported public policy decisions, as well as its due
    process argument. However, we address, as properly preserved, Exxon’s
    separation of powers argument based upon the ODD and GREE Funds.
    Before trial, Exxon moved for summary judgment on separation of
    powers grounds, arguing that the State’s suit threatened to usurp the
    legislature’s appropriations power because the ODD and GREE Funds “embody
    the legislative choice regarding how testing and remediation should be funded”
    and “this suit would allow the Attorney General to fund remediation in a very
    different way and create an appropriation outside of the General Court’s
    purview.” Exxon asserted that, because “there is no existing statutory
    mechanism through which any damages awarded to the State in this litigation
    could be specifically appropriated to the investigation, testing, and remediation
    the State requests,” it would violate separation of powers for the court or the
    attorney general “to order such an appropriation.” Thus, Exxon argued, “[i]n
    light of the existing funds and their structure, this suit implicates
    appropriations-related separation of powers problems.”
    The trial court denied the motion, concluding that Exxon had failed to
    establish that the legislature intended the ODD or GREE Funds to be the
    State’s exclusive remedy. As to the ODD Fund, the court found that pursuant
    to the plain language of RSA 146-D:6, I, and I-a, the Fund “is only authorized
    to disburse funds to owners of underground storage facilities, bulk storage
    facilities, or the land on which such facilities are stored” and, thus, the statute
    did not demonstrate legislative intent “to provide a remedy for the damages
    sought by the State in this litigation.” As to the GREE Fund, although noting
    that it does not contain an explicit limitation upon who may seek payment,
    because the potential damages at issue in this suit far exceed the $2,500,000
    capped balance of the fund, the trial court stated that
    [i]t is reasonable to infer, then, that in creating the GREE Fund the
    legislature did not intend it to serve as the sole source of cleanup
    funds for any and all contamination event[s]. Its relatively small
    size indicates that it was intended to address a small number of
    isolated incidents at any given time, not a statewide contamination
    of the type alleged here by the State. Finally, the Court notes that
    neither fund claims to be an exclusive remedy.
    Accordingly, the court found that “the existence of these funds does not evince
    the intent of the legislature to preclude suits such as this one” and that “the
    State’s suit does not threaten to usurp the legislature’s appropriations power.”
    On appeal, Exxon argues that the legislature “created two detailed
    statutory schemes—the ODD Fund and the GREE Fund—to enable direct
    spillers to pay the often substantial costs of remediation,” and that “[i]t is
    5
    precisely when the legislature has established a tailored regulatory framework
    to address a particular problem that this Court has declined to make judicial
    ‘improvements’ to the democratically-enacted scheme.” The State argues that
    its suit “is consistent with the ODD and GREE funds” in that the “caps on
    those funds, their purposes, and their structures confirm that neither was
    intended to replace recovery actions for tortious activity against manufacturers
    of dangerous products or to free manufacturers that withhold knowledge of a
    dangerous condition from liability.”
    Whether the State’s lawsuit violates the Separation of Powers Clause of
    the State Constitution, N.H. CONST. pt. I, art. 37, because it conflicts with the
    ODD and GREE Funds, is a question of law, which we review de novo. See
    Cloutier v. State, 
    163 N.H. 445
    , 451 (2012). “The separation of powers among
    the legislative, executive and judicial branches of government is an important
    part of its constitutional fabric.” Duquette v. Warden, N.H. State Prison, 
    154 N.H. 737
    , 746 (2007). “Separation of the three co-equal branches of
    government is essential to protect against a seizure of control by one branch
    that would threaten the ability of our citizens to remain a free and sovereign
    people.” 
    Id.
     Thus, under the Separation of Powers Clause, “each branch is
    prohibited . . . from encroaching upon the powers and functions of another
    branch.” 
    Id. at 746-47
    . Nevertheless, Part I, Article 37 does “not provide for
    impenetrable barriers between the branches . . . and the doctrine is violated
    only when one branch usurps an essential power of another.” 
    Id. at 747
    (citation omitted).
    Statutory interpretation is a question of law, which we review de novo.
    Appeal of Local Gov’t Ctr., 
    165 N.H. 790
    , 804 (2014). In matters of statutory
    interpretation, we are the final arbiter of the intent of the legislature, as
    expressed in the words of the statute considered as a whole. 
    Id.
     We first look
    to the language of the statute itself, and, if possible, construe that language
    according to its plain and ordinary meaning. 
    Id.
     We interpret legislative intent
    from the statute as written and will not consider what the legislature might
    have said or add language that the legislature did not see fit to include. 
    Id.
    Statutory “provisions barring [a] common law right to recover are to be strictly
    construed.” Estate of Gordon-Couture v. Brown, 
    152 N.H. 265
    , 267 (2005). “If
    such a right is to be taken away, it must be expressed clearly by the
    legislature.” 
    Id. at 266
    .
    The purpose of the ODD Fund is “to establish financial responsibility for
    the cleanup of oil discharge and disposal, and to establish a fund to be used in
    addressing the costs incurred by the owners of underground storage facilities
    and bulk storage facilities for the cleanup of oil discharge and disposal.” RSA
    146-D:1 (emphasis added). The ODD Fund allows owners of eligible facilities to
    apply for reimbursement of court-ordered damages to third parties for injury or
    property damage and costs of cleanup of oil discharges up to $1,500,000. RSA
    146-D:6, III. The ODD Fund is financed by a fee on imported oil that is paid on
    6
    a per gallon basis by distributors who import oil into New Hampshire. RSA
    146-D:2-:3. As the trial court found, “the end goal of the ODD Fund is not to
    offset tort liability for Defendants but rather to provide an excess insurance
    mechanism for [underground storage tank] owners who are otherwise in
    compliance with all relevant laws and rules.”
    The purpose of the GREE Fund, a fund in addition to both the Oil
    Pollution Control Fund established pursuant to RSA 146-A:11-a (Supp. 2014)
    and the ODD Fund, “is to provide procedures that will expedite the cleanup of
    gasoline ether spillage, mitigate the adverse [e]ffects of gasoline ether
    discharges, encourage preventive measures, impose a fee upon importers of
    neat gasoline ethers into the state and establish a fund for the remediation of
    groundwater and surface water contaminated by gasoline ethers.” RSA 146-
    G:1, II. “Th[e GREE] nonlapsing, revolving fund shall be used . . . . to mitigate
    the adverse [e]ffects of gasoline ether discharges including, but not limited to,
    provision of emergency water supplies to persons affected by such pollution,
    and . . . the establishment of an acceptable source of potable water to injured
    parties.” RSA 146-G:4, I. “Not more than $150,000 shall be allocated annually
    for research programs dedicated to the development and improvement of
    preventive and cleanup measures concerning such gasoline ether discharges.”
    
    Id.
     The fund’s balance is capped at $2,500,000. RSA 146-G:4, II. The fund is
    financed in part by the ODD Fund. RSA 146-D:3, VI(b); RSA 146-G:1.
    We agree with the trial court that there is no language in either of the
    statutory provisions establishing the ODD and GREE Funds indicating a
    legislative intent to preclude the damages sought by the State in this case. See
    also State v. Hess Corp., 
    161 N.H. 426
    , 431 (2011) (MTBE defendants conceded
    that the State may recover damages to test and treat statutorily defined public
    water systems). Accordingly, we reject Exxon’s separation of powers argument
    based upon the ODD and GREE Funds.
    III. Waiver
    Exxon argues that the State’s suit should have been dismissed due to
    waiver. Before trial, Exxon moved for summary judgment, arguing, in part,
    that “by requiring that RFG . . . gasoline be sold in New Hampshire, with full
    knowledge that such gasoline would contain MTBE and with full knowledge of
    all of MTBE’s alleged defective properties, the State cannot now be allowed to
    sue Defendants who thereafter complied with the State’s demands and
    supplied MTBE gasoline to the State.” (Quotation omitted.) In denying the
    motion, the trial court noted that, because Exxon did not assert that the State
    expressly waived its right to sue for harm from MTBE, Exxon could only
    proceed under an implied waiver theory. The court found that there were
    “genuine issues of disputed fact regarding the State’s knowledge, [Exxon’s]
    knowledge, and timing of this awareness.”
    7
    Following the jury verdict, Exxon moved to set aside the verdict and for a
    new trial. Exxon argued, in part, that it was “unfairly prejudiced” when the
    trial court instructed the jury on waiver in its preliminary instructions “but
    then refused to include that instruction in its final instructions or in the verdict
    form.” In its order denying Exxon’s motion, the trial court explained:
    In its motion for summary judgment on waiver, Exxon
    argued that the State knew MTBE’s characteristics but still opted
    in to the RFG program, thereby waiving any claims it had or would
    develop regarding MTBE contamination. However, the State
    disputed its level of knowledge. During trial, Exxon attempted to
    prove the State’s knowledge by presenting witnesses that testified
    that MTBE’s characteristics were widely known and understood
    thereby suggesting the State should have known about MTBE.
    The State countered this testimony with its own witnesses
    explaining that the first time State employees found MTBE in a
    contamination site, those employees were unable to identify the
    compound and asked the U.S. EPA for assistance. The State also
    presented testimony that it did not become aware of MTBE’s full
    nature until the State of Maine published a study.
    This testimony goes to the issue of waiver but it is also
    relevant to the issue of [the State’s] misconduct, and the Court
    gave an instruction on [the State’s] misconduct. In fact, the Court
    instruction on [the State’s] misconduct encompassed the same
    elements embodied in a waiver claim.
    (Citations omitted.)
    On appeal, Exxon argues that, “with knowledge of MTBE groundwater
    risks, the State opted-in to the RFG program, participated in that program for
    years, repeatedly opposed banning MTBE, and ultimately decided in 2004 that
    continuing MTBE’s use for nearly three more years was better for the State
    than an outright ban.” Thus, there was “ample evidence to support a jury
    verdict finding waiver,” and the trial court’s “failure to instruct the jury is clear
    error.” Exxon also argues that the trial court’s reasoning that a waiver
    instruction was unnecessary is erroneous, “as misconduct and waiver are
    distinct defenses that are appropriately charged separately.” The State argues
    that, at trial, Exxon adduced no evidence of express or implied waiver, that the
    special verdict form reflects that the jury rejected Exxon’s defense “that the
    hazards posed by the use of MTBE in gasoline were obvious, or were known
    and recognized by the State,” and that, in any event, the trial court “correctly
    concluded that its misconduct instruction adequately encompassed Exxon’s
    waiver defense.”
    8
    Whether a particular jury instruction is necessary and the exact scope
    and wording of jury instructions are within the sound discretion of the trial
    court. See State v. Littlefield, 
    152 N.H. 331
    , 334 (2005). We review the trial
    court’s decisions on these matters for an unsustainable exercise of discretion.
    
    Id.
    Exxon’s “plaintiff’s misconduct defense” jury instruction as given by the
    trial court provided in pertinent part:
    If you find that ExxonMobil’s product was unreasonably
    dangerous, ExxonMobil failed to provide a warning, or behaved
    negligently and that ExxonMobil is liable, you should then go on to
    determine if the State committed misconduct that contributed to
    cause its injuries. With respect to the State’s alleged misconduct,
    ExxonMobil bears the burden to prove that it is more likely than
    not that the State committed misconduct in its use of the product.
    Misconduct includes, but is not limited to, abnormal use of
    the product, misuse of the product, failing to discover or foresee
    dangers that the ordinary person or entity would have discovered
    or foreseen, voluntarily proceeding to encounter a known danger,
    and failing to mitigate damages.
    (Emphasis added.)
    We note that in its motion for judgment notwithstanding the verdict
    (JNOV) following the jury verdict, Exxon made the same argument regarding its
    misconduct defense that it makes on appeal regarding waiver. Asserting in its
    motion for JNOV that the evidence “overwhelmingly proved ExxonMobil’s
    affirmative defenses,” Exxon argued that “[t]he evidence at trial overwhelmingly
    proves that the State’s misconduct contributed to its injuries. First, the
    evidence established that the State voluntarily encountered a known danger by
    opting-in to the RFG program with knowledge of MTBE’s characteristics.
    Moreover, the evidence demonstrates that the State knew that MTBE would be
    used in New Hampshire to comply with the RFG program.” (Citation omitted.)
    In support of its waiver argument on appeal, Exxon asserts that “with
    knowledge of MTBE groundwater risks, the State opted-in to the RFG program
    [and] participated in that program for years.”
    Concluding that the waiver and misconduct instructions are similar
    because they both address the State’s knowledge and subsequent actions
    based upon that knowledge, the trial court reasoned:
    Depending on the State’s knowledge, the jury could have
    found that the State knew or should have known the
    characteristics of MTBE gasoline and thereby either waived any
    9
    challenge it is now raising or should have been held partially
    responsible for its own injury. In other words, because the jury
    was instructed on and considered the issue of the State’s
    knowledge—that the State knew of MTBE and used it anyway—the
    jury also considered whether the State waived any claims about
    MTBE contamination risks by knowingly using MTBE. The jury
    nonetheless rejected this theory. Thus, Exxon was not entitled to
    an independent waiver instruction because the plaintiff’s
    misconduct instruction encompassed this affirmative defense.
    Assuming, without deciding, that there was enough evidence for Exxon’s
    implied waiver defense to go to the jury, we hold that any error was harmless
    given the jury’s finding that the State did not commit misconduct that
    contributed to its harm.
    IV. Federal Preemption
    Exxon argues that the State’s claims are preempted by the Federal Clean
    Air Act. Before trial, Exxon moved for summary judgment, arguing that
    Congress and the EPA “took actions providing that federal requirements were
    to be met by allowing refiners to choose MTBE as an additive to gasoline,” and
    that “State law is preempted where it seeks to ban an action that federal law
    affirmatively chooses to make available to state actors.” The trial court rejected
    Exxon’s argument that the State’s tort claims present an obstacle to the federal
    purpose of the Clean Air Act.
    Noting that “[o]n numerous occasions, courts throughout the United
    States have considered whether the [Clean Air Act] preempts state tort law
    claims regarding the use of MTBE,” the trial court applied the reasoning of the
    United States District Court for the Southern District of New York. The trial
    court explained that Exxon’s arguments
    are essentially identical to those made by the defendants during In
    re MTBE Products Liability Litigation. Here, the Defendants claim
    that the federal regulation deliberately provided manufacturers
    with a range of oxygenate choices and the choice was designed to
    further the regulation’s objectives. The Defendants further argue
    that Congress and the EPA stressed the importance of MTBE as a
    choice and encouraged its use. Finally, they point to the lengthy
    legislative history of the [Clean Air Act] to support their arguments.
    See In re Methyl Tertiary Butyl Ether (MTBE) Products, 
    457 F. Supp. 2d 324
    ,
    336-42 (S.D.N.Y. 2006), aff’d, 
    725 F.3d 65
     (2d Cir. 2013), cert. denied, 
    134 S. Ct. 1877
     (2014). The trial court concluded that “[l]ike the defendants [in MTBE
    Products], the Defendants here have failed to prove that the State’s tort law
    10
    claims are preempted by the [Clean Air Act], and their use of the legislative
    history is irrelevant due to the unambiguous language of the [Act].”
    Exxon moved for a directed verdict at the close of the State’s case-in-
    chief, based in part upon its assertion that the evidence presented
    “demonstrates that the State’s claims are preempted based on the Clean Air
    Act’s requirement that gasoline contain an oxygenate and the factual evidence
    demonstrating that no feasible alternative oxygenate existed sufficient to meet
    the requirements of RFG in New Hampshire.” Noting that Exxon’s argument “is
    presented in a highly summary fashion,” the trial court declined to revisit the
    preemption claim and relied upon its earlier decision denying Exxon’s motion
    for summary judgment.
    After the jury verdict, Exxon moved to set aside the verdict and for a new
    trial arguing, in part, that the trial court “failed to instruct the jury on
    ExxonMobil’s affirmative defense of preemption or include it in the verdict
    form.” According to Exxon, the trial court erred because “there were sufficient
    facts” to support its argument “that MTBE was the only feasible oxygenate for
    use in New Hampshire” and, therefore, “the State’s claim would be preempted
    because ExxonMobil was required to use an oxygenate under the Clean Air Act
    Amendments.” Exxon asserted also that “as a matter of law, the State’s claims
    were preempted . . . because Congress specifically intended for refiners to be
    able to choose among oxygenates, including MTBE, to comply with the RFG
    program and eliminating MTBE would have interfered with the goals of the
    [Act].”
    Noting that “[t]he preemption argument Exxon raises directly alleges the
    argument it raised pretrial and in its directed verdict motion,” the trial court
    denied the motion. The court reasoned that
    [t]o the extent Exxon argues the jury should have been instructed
    on preemption in order to find facts from which the Court could
    further evaluate preemption, the Court considered and rejected
    this argument in its [order denying Exxon’s motion for a directed
    verdict]. Even assuming New Hampshire courts would adopt this
    view of preemption, there are no facts to support Exxon’s theory.
    Exxon alleges the State’s claims are preempted by the federal
    Clean Air Act and its RFG program. The Court rejected this legal
    argument. There are no facts that a jury could find that would
    alter the legal analysis this Court already undertook.
    (Citation omitted.)
    On appeal, Exxon argues that a state tort duty holding it liable for
    supplying MTBE is preempted by the Clean Air Act, “particularly because
    Exxon had no safer, feasible alternative to MTBE at the time.” According to
    11
    Exxon, “[p]reemption here follows a fortiori from” Geier v. American Honda
    Motor Co., 
    529 U.S. 861
     (2000), and Williamson v. Mazda Motor of America,
    Inc., 
    562 U.S. 323
     (2011), “which establish that when federal law imposes a
    mandate but leaves private parties with a choice of how to comply, a state-law
    tort duty that would take one option off the table obstructs federal objectives
    when maintaining the choice is a ‘significant objective’ of the federal program.”
    Exxon asserts that despite “ample evidence that there was no safer, feasible
    alternative to MTBE,” the trial court erroneously refused to instruct the jury on
    this issue. The State argues that “[p]reemption arguments like the one Exxon
    raises here have been rejected by every federal court of appeals to consider
    them.” The State contends that “enabling suppliers to choose MTBE (as
    opposed to ethanol) was not a significant regulatory objective of Congress or
    EPA,” and that the trial evidence demonstrated that “safer, feasible alternatives
    to MTBE existed.” (Quotations omitted.)
    Because the trial court’s determination of federal preemption is a matter
    of law, our review is de novo. N.H. Attorney Gen. v. Bass Victory Comm., 
    166 N.H. 796
    , 801 (2014). The federal preemption doctrine is based upon the
    Supremacy Clause of the United States Constitution. See Arizona v. United
    States, 
    132 S. Ct. 2492
    , 2500 (2012); see also Appeal of Sinclair Machine
    Prod’s, Inc., 
    126 N.H. 822
    , 826 (1985). Article VI provides that federal law
    “shall be the supreme law of the land; and the judges in every state shall be
    bound thereby, anything in the Constitution or laws of any state to the
    contrary notwithstanding.” U.S. CONST. art. VI. “Accordingly, it has long been
    settled that state laws that conflict with federal law are without effect.” Mutual
    Pharmaceutical Co., Inc. v. Bartlett, 
    133 S. Ct. 2466
    , 2473 (2013) (quotation
    omitted).
    Congress may preempt state law under the Supremacy Clause in several
    ways. Hillsborough County v. Automated Medical Labs., 
    471 U.S. 707
    , 713
    (1985). First, within constitutional limits, “Congress is empowered to pre-empt
    state law by so stating in express terms.” 
    Id.
     “In the absence of express pre-
    emptive language, Congress’ intent to pre-empt all state law in a particular
    area may be inferred where the scheme of federal regulation is sufficiently
    comprehensive to make reasonable the inference that Congress left no room for
    supplementary state regulation.” 
    Id.
     (quotation omitted).
    “Even where Congress has not completely displaced state regulation in a
    specific area, state law is nullified to the extent that it actually conflicts with
    federal law.” 
    Id.
     This “conflict preemption” arises when “compliance with both
    federal and state regulations is a physical impossibility, or when state law
    stands as an obstacle to the accomplishment and execution of the full
    purposes and objectives of Congress.” 
    Id.
     (quotations and citation omitted).
    Exxon relies upon the so-called “obstacle branch” of conflict
    preemption — that state law “stand[s] as an obstacle to the accomplishment
    12
    and execution of the full purposes and objectives of Congress.” Arizona, 
    132 S. Ct. at 2501
     (quotation omitted). “The burden of establishing obstacle
    preemption . . . is heavy: the mere fact of tension between federal and state
    law is generally not enough to establish an obstacle supporting preemption,
    particularly when the state law involves the exercise of traditional police
    power.” MTBE Products Liability Litigation, 
    725 F.3d 65
    , 101-02 (2d Cir. 2013)
    (quotations and brackets omitted), cert. denied, 
    134 S. Ct. 1877
     (2014).
    “Indeed, federal law does not preempt state law under obstacle preemption
    analysis unless the repugnance or conflict is so direct and positive that the two
    acts cannot be reconciled or consistently stand together.” 
    Id. at 102
     (quotation
    omitted).
    “The control and elimination of water pollution is a subject clearly within
    the scope of the police power” of the State. Shirley v. Commission, 
    100 N.H. 294
    , 299 (1956). “Consideration of issues arising under the Supremacy Clause
    starts with the assumption that the historic police powers of the States are not
    to be superseded by Federal Act unless that is the clear and manifest purpose
    of Congress.” Cipollone v. Liggett Group, Inc., 
    505 U.S. 504
    , 516 (1992)
    (quotation, brackets, and ellipses omitted). “Accordingly, the purpose of
    Congress is the ultimate touchstone of pre-emption analysis.” 
    Id.
     (quotations
    and brackets omitted). “Since preemption of any type fundamentally is a
    question of congressional intent, our preemption analysis begins with the
    source of the alleged preemption.” Bass Victory Comm., 166 N.H. at 803
    (quotation, brackets, and citation omitted).
    As discussed above, in 1990, Congress enacted amendments to the
    Clean Air Act that, among other things, created the RFG Program. See 
    42 U.S.C. § 7545
    (k). The RFG Program required gasoline used in specific
    geographic areas to have a minimum oxygen content, achieved by the addition
    of an oxygenate of the manufacturer’s choice. See 
    42 U.S.C. §§ 7545
    (k)(2)(B),
    (m)(2); see also 
    40 C.F.R. § 80.46
    (g)(9)(i). After the passage of the amendments,
    the EPA certified various blends of gasoline for use in the RFG Program,
    including gasoline containing MTBE, but did not mandate the use of any one
    oxygenate. As the United States Court of Appeals for the Second Circuit
    explained,
    the 1990 Amendments did not require, either expressly or
    implicitly, that Exxon use MTBE. Although the 1990 Amendments
    required that gasoline in certain geographic areas contain a
    minimum level of oxygen, they did not prescribe a means by which
    manufacturers were to comply with this requirement. The EPA
    identified MTBE as one additive that could be used to “certify”
    gasoline, but certification of a fuel meant only that it satisfied
    certain conditions in reducing air pollution. Neither the statute
    13
    nor the regulations required Exxon to use MTBE, rather than other
    oxygenates, such as ethanol, in its gasoline.
    MTBE Products Liability Litigation, 725 F.3d at 98 (citations omitted).
    We disagree with Exxon that preemption here “follows a fortiori” from
    Geier and Williamson. Those cases both considered portions of Federal Motor
    Vehicle Safety Standard 208 (FMVSS 208), promulgated pursuant to the
    National Traffic and Motor Vehicle Safety Act of 1966. In Geier, a 1984 version
    of FMVSS 208 required manufacturers to equip their vehicles with passive
    restraint systems, but gave manufacturers a choice among several different
    passive restraint systems, including airbags and automatic seatbelts. Geier,
    
    529 U.S. at 864-65, 875
    . The question before the United States Supreme
    Court was whether the Act, together with the regulation, preempted a state tort
    suit that would have held a manufacturer liable for not installing airbags. See
    
    id. at 865
    . In determining whether, in fact, the state tort action conflicted with
    federal law, the Court considered whether the state law stood as an “obstacle”
    to the objectives of the federal law. 
    Id. at 886
    . After examining the regulation,
    including its history, the promulgating agency’s contemporaneous explanation
    of its objectives, and the agency’s current views of the regulation’s preemptive
    effect, the Court concluded that giving auto manufacturers a choice among
    different kinds of passive restraint devices was a significant objective of the
    federal regulation. 
    Id. at 874-83
    . Because the tort suit stood as an obstacle to
    the accomplishment of that objective in that the suit would have deprived the
    manufacturers of the choice among passive restraint systems that the federal
    regulation gave them, the Court found the state tort suit preempted. 
    Id. at 886
    .
    In Williamson, the Supreme Court considered a 1989 version of FMVSS
    208 requiring that auto manufacturers install seatbelts on the rear seats of
    passenger vehicles. Williamson, 
    562 U.S. at 326
    . The law required
    manufacturers to install lap-and-shoulder belts on seats next to a vehicle’s
    doors or frames but gave them a choice of installing either simple lap belts or
    lap-and-shoulder belts on rear inner seats. 
    Id.
     The Court noted that like the
    regulation in Geier, the regulation at issue before it left the manufacturer with
    a choice and, like the tort suit in Geier, the tort suit at issue would restrict that
    choice. 
    Id. at 332
    . However, after reviewing the history of the regulation before
    it, including the agency’s explanation of the reasons for not requiring lap-and-
    shoulder belts for rear inner seats and the Solicitor General’s representations
    of the agency’s views, the Court concluded that providing manufacturers with
    this seatbelt choice was not a significant objective of the federal regulation. 
    Id. at 334-36
    . Thus, the Court concluded that because the choice of the type of
    restraint was not a significant regulatory objective, the state tort suit was not
    preempted. 
    Id.
    14
    Exxon does not point to any part of the Clean Air Act or its legislative
    history that supports a conclusion that the choice among oxygenate options
    was a significant objective of the federal law. Indeed, “[t]he [Clean Air Act] itself
    contains no language mandating that [Exxon] have a choice among
    oxygenates.” In re Methyl Tertiary Butyl Ether (MTBE) Products, 
    457 F. Supp. 2d at 336-37
    . Unlike Geier, in which the federal regulation deliberately
    provided the manufacturer with a range of choices among different passive
    restraint devices, “[h]ere, the choice of oxygenate options is a means towards
    improving air quality, and the existence of the choice itself is not critical to
    furthering that goal.” MTBE Products Liability Litigation, 725 F.3d at 98 n.15.
    “Geier does not stand . . . for the proposition that any time an agency gives
    manufacturers a choice between two or more options, a tort suit that imposes
    liability on the basis of one of the options is an obstacle to the achievement of a
    federal regulatory objective and may be pre-empted.” Williamson, 
    562 U.S. at 337
     (Sotomayor, J., concurring). Rather, “a conflict results only when [the
    regulation] . . . does not just set out options for compliance, but also provides
    that the regulated parties must remain free to choose among those options.”
    
    Id. at 338
     (quotation omitted).
    We reject Exxon’s argument that “[d]espite ample evidence that there was
    no safer, feasible alternative to MTBE,” the trial court’s refusal to instruct the
    jury on this issue was error because “preemption questions can be informed by
    questions of fact.” Exxon asserts that “[a]t the summary judgment stage, the
    [trial court] rejected the purely legal argument that the State’s claims would be
    preempted even if there were safer, feasible alternatives, but later . . . refused
    to consider the different and fact-dependent question whether preemption
    would apply if Exxon had no safer, feasible alternative.” (Citation omitted.)
    The record shows, however, that Exxon’s proposed jury instruction did
    not ask the jury to find whether there was no safer feasible alternative to
    MTBE. Rather, the proposed instruction asked “whether prohibiting the use of
    MTBE in gasoline during the period at issue here would have resulted in delays
    and increased costs to the expansion of the federal RFG program,” thus
    establishing preemption. (Emphasis added.) This position has been rejected
    as a matter of law. See MTBE Products Liability Litigation, 725 F.3d at 103
    (although legislative materials demonstrate that Congress was sensitive to the
    magnitude of the economic burdens it might be imposing by virtue of the RFG
    Program, “they hardly establish that Congress had a ‘clear and manifest intent’
    to preempt state tort judgments that might be premised on the use of one
    approved oxygenate over a slightly more expensive one”); Oxygenated Fuels
    Ass’n Inc., 
    331 F.3d at 673
     (plaintiff “offered virtually no support for its
    assertion that the Clean Air Act’s goals—for purposes of preemption analysis—
    are a smoothly functioning market and cheap gasoline”).
    We agree with several other courts that have addressed and rejected the
    issue of preemption and MTBE. See, e.g., MTBE Products Liability Litigation,
    15
    725 F.3d at 100-03 (rejecting Exxon’s obstacle branch preemption arguments);
    In re Methyl Tertiary Butyl Ether (MTBE) Products, 739 F. Supp. 2d at 601-02
    (allowing plaintiffs to recover damages for inordinate environmental effects
    caused by the use of MTBE does not conflict with federal policy, and rejecting
    Exxon’s arguments that because there was no safer, feasible alternative to
    MTBE, it was impossible for Exxon to comply with federal requirements
    without using MTBE); In re Methyl Tertiary Butyl Ether (MTBE) Products, 
    457 F. Supp. 2d at 343
     (“Just as the many other courts that have addressed the
    issue of preemption and MTBE, this Court finds that plaintiffs’ tort law claims
    are not preempted.”); Oxygenated Fuels Ass’n, Inc. v. Pataki, 
    293 F. Supp. 2d 170
    , 172, 182-83 (N.D.N.Y. 2003) (concluding after bench trial that New York
    MTBE ban does not conflict with any aspect of Clean Air Act); Exxon Mobil
    Corp. v. U.S. E.P.A., 
    217 F.3d 1246
    , 1256 (9th Cir. 2000) (Nevada regulation
    requiring that all gasoline sold in wintertime have an oxygen content of at least
    3.5 percent does not conflict with, and is not preempted by, any provision of
    the Clean Air Act); Abundiz v. Explorer Pipeline Co., No. CIV. 3:00-CV-H,
    00-2029, 
    2002 WL 1592604
    , at *3-5 (N.D. Tex. July 17, 2002) (Geier does not
    compel a finding that state MTBE regulations are preempted).
    We hold as a matter of law that the State’s claims are not preempted by
    federal law, and that the trial court did not err in refusing Exxon’s proposed
    jury instruction.
    V. Standard of Care
    Exxon argues that the State failed to establish that it departed from the
    applicable standard of care “simply by marketing MTBE.” In its motion for a
    directed verdict at the close of the State’s case-in-chief, Exxon argued that “[i]n
    order to establish that ExxonMobil breached its duty of care, the State was
    obligated to present evidence that ExxonMobil failed to act pursuant to what
    reasonable prudence would require under similar circumstances.” (Quotation
    omitted.) Exxon asserted that, because the evidence presented at trial
    “demonstrated that the entire industry acted in the same manner in using
    gasoline containing MTBE in New Hampshire,” there was “no evidence to
    establish the standard of care or what a reasonable manufacturer or supplier
    would have done, let alone that ExxonMobil deviated from any applicable
    standard of care.”
    The trial court denied Exxon’s motion, rejecting its argument that
    because the State did not present evidence regarding the care exercised by
    other manufacturers and refiners in the industry, the State failed to show that
    Exxon’s actions were unreasonable. The court stated:
    In fact, the State presented testimony from Duane Bordvick
    regarding the risk-benefit analysis his company, Tosco—another
    manufacturer during the relevant time period of this case—
    16
    conducted. Bordvick testified that Tosco decided not to use MTBE
    because of the unique and increased risks Tosco perceived MTBE
    to have. This testimony not only directly contradicts Exxon’s
    argument that the State failed to show the care exercised by other
    members of the refining industry, it also serves as some evidence
    from which a jury could conclude that Exxon’s behavior in
    selecting MTBE as its RFG formula oxygenate and doing so without
    providing a warning was unreasonable.
    (Citations omitted.) The trial court also rejected, as unsupported by the record,
    Exxon’s argument that it could not have foreseen all manners in which the
    State’s alleged harm occurred. The court stated:
    The State admitted Barbara Mickelson’s memorandum to Exxon
    that demonstrates Exxon received warnings against the use of
    MTBE—that MTBE would take longer and cost more to remediate
    than traditional gasoline spills. Other witnesses corroborated
    Exxon’s possession of information regarding the expense
    associated with MTBE remediation as early as the 1980s. In this
    way, a reasonable jury could conclude that Exxon should have
    foreseen the harm the State now alleges—increased remediation
    costs of a different nature than those associated with traditional
    gasoline.
    (Citations omitted.)
    Following the jury verdict, Exxon moved for JNOV, arguing, in part, that
    “there is no evidence in the record regarding the standard of care for a
    reasonably prudent refiner or manufacturer or what actions ExxonMobil took
    that breached a standard of care” when the decision to use MTBE was made.
    Exxon asserted that it presented testimony showing that it “carefully
    considered the use of MTBE,” including consulting with “[a]t least nine different
    groups within Exxon” to gain information, and that “[o]ther gasoline refiners
    and manufacturers agreed with Exxon’s assessment that the RFG program’s
    requirements could not have been met without the use of MTBE in addition to
    ethanol.” Noting that it had previously rejected Exxon’s arguments in its
    directed verdict ruling, the trial court relied upon that ruling in declining to
    consider these arguments again “[b]ecause Exxon raises no new facts or law.”
    On appeal, Exxon argues that the State “offered no evidence to support
    the notion that a reasonable supplier in New Hampshire would never have used
    MTBE at any time” and that “[w]ithout a relevant standard against which to
    compare Exxon’s conduct, the State’s negligence claim . . . fails as a matter of
    state law.” According to Exxon, the State failed to establish that it departed
    from the applicable standard of care simply by marketing MTBE, asserting that
    “the evidence presented at trial showed that manufacturers overwhelmingly
    17
    complied with the RFG program in the Northeast by using MTBE because there
    was no safer, feasible alternative.” The State argues that “[t]he record contains
    ample evidence that Exxon breached the standard of care,” the trial court
    properly instructed the jury regarding the duty of care, and the jury found
    Exxon negligent.
    Weighing the evidence is a proper function of the factfinder. 93 Clearing
    House, Inc. v. Khoury, 
    120 N.H. 346
    , 350 (1980). The trier of fact is in the best
    position to measure the persuasiveness of evidence and the credibility of
    witnesses. 
    Id.
     Factual findings “will not be disturbed unless . . . erroneous as
    a matter of law or unsupported by the evidence.” Great Lakes Aircraft Co. v.
    City of Claremont, 
    135 N.H. 270
    , 287 (1992) (quotations omitted); see Sutton v.
    Town of Gilford, 
    160 N.H. 43
    , 55 (2010). “A fact finder has the discretion to
    evaluate the credibility of the evidence and may choose to reject that evidence
    in whole or in part.” Society Hill at Merrimack Condo. Assoc. v. Town of
    Merrimack, 
    139 N.H. 253
    , 256 (1994). Our task is to determine whether a
    reasonable person could reach the same conclusion as the jury on the basis of
    the evidence before it. See Shaka v. Shaka, 
    120 N.H. 780
    , 782 (1980). We
    review sufficiency of the evidence claims as a matter of law. Tosta v. Bullis,
    
    156 N.H. 763
    , 767 (2008).
    The test of due care is what reasonable prudence would require under
    similar circumstances. Carignan v. N.H. Int’l Speedway, 
    151 N.H. 409
    , 414
    (2004). Whether the defendant breached that duty of care is a question for the
    trier of fact. 
    Id.
     “[N]ot every risk that might be foreseen gives rise to a duty to
    avoid a course of conduct; a duty arises because the likelihood and magnitude
    of the risk perceived is such that the conduct is unreasonably dangerous.”
    Millis v. Fouts, 
    144 N.H. 446
    , 449 (1999) (quotation omitted). “[C]onformity
    with industry practice is not an absolute defense to liability under New
    Hampshire law, because entire industries may lag behind the standard of care.
    But it is nonetheless a factor that the jury may consider in evaluating
    negligence claims.” Bartlett v. Mutual Pharmaceutical Co., Inc., 
    742 F. Supp. 2d 182
    , 189 (D.N.H. 2010) (quotation and citation omitted); see Bouley v.
    Company, 
    90 N.H. 402
    , 403 (1939) (the test of due care is not custom or usage,
    but what reasonable prudence would require under the circumstances).
    The record supports that in April 1984, an Exxon employee stated in an
    internal memo that “we have . . . ethical and environmental concerns [about
    MTBE] that are not too well defined at this point.” The memo explained that as
    there were “strong economic incentives to use MTBE, a study should be started
    [to] thoroughly review the issues with management.” In August 1984, Exxon
    asked an in-house environmental engineer, Barbara Mickelson, for
    “information on additional potential ground water contamination problems that
    are associated with the use of MTBE in gasoline.” Mickelson stated that
    “MTBE when dissolved in ground water, will migrate farther than [another
    gasoline additive] before soil attenuation processes stop the MTBE migration.”
    18
    She explained that the “[s]mall household carbon filtration units . . . used by
    Exxon to treat private drinking supplies contaminated by [another gasoline
    additive] . . . would not provide adequate treatment for water supplies
    additionally contaminated by MTBE.” Mickelson concluded that “the number
    of well contamination incidents is estimated to increase three times following
    the widespread introduction of MTBE into Exxon gasoline” and that “the
    closing-out of these incidents would take longer and treatment costs would be
    higher by a factor of 5.” In 1985, Mickelson recommended that “from an
    environmental risk point of view MTBE not be considered as an additive to
    Exxon gasolines on a blanket basis throughout the United States” because of
    its unique contaminating properties.
    In the 1980s, Exxon joined the MTBE Committee, an industry group that
    was formed to address “environmental issues” and “federal and state regulatory
    issues” relating to MTBE. In a December 1986 meeting with MTBE Committee
    members, including Exxon, the EPA expressed concern about MTBE leaking
    into groundwater because MTBE, “which is very soluble in water, can find its
    way to drinking supplies (i.e. acqu[i]fers).” Nonetheless, in February 1987, the
    MTBE Committee represented to the EPA that
    there is no evidence that MTBE poses any significant risk of harm
    to health or the environment, that human exposure to MTBE and
    release of MTBE to the environment is negligible, that sufficient
    data exists to reasonably determine or predict that manufacture,
    processing, distribution, use and disposal of MTBE will not have
    an adverse effect on health or the environment, and that testing is
    therefore not needed to develop such data.
    After Congress amended the Clean Air Act in 1990 to require use of an
    oxygenate in gasoline, members of the American Petroleum Institute, an
    industry lobbying group that included Exxon, met with New Hampshire
    officials and encouraged them to opt in to the RFG Program. During those
    meetings, it was not disclosed that oil companies would use MTBE in RFG
    Program gasoline. Robert Varney, who was the commissioner of DES during
    the relevant time, testified that, although Exxon knew as early as 1984 about
    MTBE groundwater contamination issues, Exxon did not warn the State or
    provide it with any information about those issues before Varney recommended
    that the State opt in to the RFG Program in 1991 or before he recommended
    that it remain in the Program in 1997. He also testified that the State would
    not have opted in to the RFG Program if DES had known the information
    contained in Mickelson’s 1984 memo.
    In 1999, Exxon had identified more than 100 known contamination sites
    in New England, many polluted solely with MTBE. That same year, a study by
    Exxon on the costs of cleaning up MTBE noted that spills containing MTBE
    could be more difficult and costly to clean up because MTBE “is more soluble
    19
    [in water] and less biodegradable than other gasoline components.” The study
    found that “[c]ost increases related to MTBE are significant for . . . New
    England” due in part to “hydrogeologic site conditions which maximize the
    potential for MTBE to ‘travel’ and impact receptors (e.g., shallow groundwater,
    fractured bedrock, a high density of private potable wells).” In 2000, Exxon
    employees observed in an internal communication that “industry has not
    demonstrated the ability to stop leaks and spills to the level required to avoid
    MTBE concentrations that effect [sic] the taste and odor in drinking water,”
    that “non MTBE fuel leaks are more managable [sic],” and that “[b]ased on
    experience in [the] US, it is fair to assume that other places using MTBE will
    eventually find groundwater contamination.”
    Duane Bordvick, a former senior vice-president for safety, health and
    environment at Tosco Corporation, a gasoline refinery in California, testified
    that in 1997 he made a statement on behalf of Tosco that the company had
    decided “that long-term use of MTBE was not in the best interest of” the
    company or its shareholders due to the “potential threat to California’s
    drinking water resources and the associated liability . . . for restoring water
    resources.” He testified that that conclusion was drawn based upon several
    factors including: “the growing evidence on the threat of MTBE contamination
    and evidence related to the difficulty of cleaning up MTBE”; “the cost
    associated [with] potentially having to participate in replacement of drinking
    water to cities”; “the potential liability for the use of MTBE, associated legal
    costs, [and] potential lawsuits that may result”; and the “likelihood” that those
    costs “would exceed . . . whatever costs may be associated with no longer
    relying on MTBE in [Tosco’s] gasoline,” including refinery changes and other
    equipment changes.
    As the trial court instructed the jury:
    Negligence is the failure to use reasonable care. Reasonable
    care is the degree of care that an ordinary, prudent manufacturer
    or supplier would use under the same or similar circumstances.
    The failure to use reasonable care may take the form of
    action or inaction. That is, negligence may consist of either: doing
    something that an ordinary, prudent manufacturer or supplier
    would not do under the same or similar circumstances; or, failing
    to do something that an ordinary, prudent manufacturer or
    supplier would do under the same or similar circumstances.
    A manufacturer or supplier has a duty to make inspections
    or tests that are reasonably necessary to see that its product is
    safe for its intended use and for any other reasonably foreseeable
    purpose.
    20
    Viewed in the light most favorable to the State, we hold that the record
    contains sufficient evidence to support a finding that Exxon breached the
    standard of care by acting unreasonably under the circumstances.
    Accordingly, we uphold the trial court’s rulings.
    VI. Duty to Warn
    Exxon argues that it did not have a duty to warn the government as
    sovereign, rather than as end user or consumer, of the characteristics of MTBE
    gasoline. In 2008, Exxon moved to dismiss the State’s failure-to-warn claim,
    alleging that when the State claims that, as a bystander, it is a consumer of
    MTBE, and is therefore entitled to bring a products liability claim, it improperly
    expands the definition of “consumer,” and that the State should be classified as
    a third party bystander. Because New Hampshire does not recognize bystander
    liability claims, Exxon argued that the State’s strict liability claims should be
    dismissed.
    The trial court denied the motion, finding that the State’s claim regarding
    Exxon’s alleged failure to warn of its defective product had been properly
    pleaded. Based upon RSA 481:1 (2013), the court concluded that because the
    State “holds the waters of New Hampshire in trust for the public,” the State
    had properly alleged that “the defendants may be sought to be held liable for
    damage to the State’s waters.” The trial court rejected the argument that “the
    State’s interests in its water are akin to those of a bystander.” Several years
    later, Exxon moved for summary judgment on the State’s failure-to-warn claim,
    arguing that because the State was not a “user” or “consumer” of MTBE it
    “cannot premise a failure-to-warn claim on [Exxon’s] alleged failure to warn the
    State itself.” The trial court agreed with the State that the issue had already
    been addressed in the prior order on the motion to dismiss.
    In its motion for a directed verdict at the close of the State’s case-in-
    chief, Exxon argued, in part, that the State “failed to introduce evidence that
    ExxonMobil failed to warn ‘users’ of gasoline containing MTBE, instead
    focusing exclusively on ExxonMobil’s alleged failure to warn the State as a
    regulatory entity, not as a user.” The trial court rejected Exxon’s arguments,
    stating that “the State is the party who—if a jury determined a warning was
    required—would have been owed the warning.” The court explained that “[t]he
    State, as the consumer and in its parens patriae capacity, was an end user of
    MTBE gasoline. This Court has previously ruled the State has standing to
    assert claims brought on behalf of the people of New Hampshire. Additionally,
    the State is a consumer itself.”
    On appeal, Exxon argues that “[t]he theory that there is a duty to warn
    the sovereign qua sovereign” is “wholly unprecedented, oversteps longstanding
    limitations of New Hampshire tort law, and raises serious First Amendment
    difficulties.” The State argues that “although Exxon contends that the verdict
    21
    hinges on the State’s status as sovereign, the trial evidence clearly
    demonstrated that Exxon provided no warning about MTBE to anyone” and
    that Exxon, thus, “failed to warn the State as regulator, the State as an end
    user, or the citizenry represented by the State as parens patriae.” We agree
    with the State.
    The General Court has declared that the State is the trustee over all of
    the State’s water. Pursuant to RSA 481:1,
    an adequate supply of water is indispensable to the health, welfare
    and safety of the people of the state and is essential to the balance
    of the natural environment of the state. Further, the water
    resources of the state are subject to an ever-increasing demand for
    new and competing uses. The general court declares and
    determines that the water of New Hampshire whether located
    above or below ground constitutes a limited and, therefore,
    precious and invaluable public resource which should be
    protected, conserved and managed in the interest of present and
    future generations. The state as trustee of this resource for the
    public benefit declares that it has the authority and responsibility
    to provide careful stewardship over all the waters lying within its
    boundaries.
    RSA 481:1. As trustee, the State can bring suit to protect from contamination
    the waters over which it is trustee. Hess, 161 N.H. at 432.
    In State v. City of Dover, 
    153 N.H. 181
     (2006), we determined that the
    State was the proper party to bring suit against the MTBE defendants, because
    it “has a quasi-sovereign interest in protecting the health and well-being, both
    physical and economic, of its residents with respect to the statewide water
    supply.” City of Dover, 153 N.H. at 186. In addition, we concluded that the
    State satisfied the requirements of parens patriae standing because it asserted
    an injury to a quasi-sovereign interest, and alleged injury to a substantial
    segment of its population. Id. at 187-88. “[A] state may act as the
    representative of its citizens where the injury alleged affects the general
    population of a State in a substantial way.” Hess, 161 N.H. at 433 (quotation
    omitted). Accordingly, we held that the State has parens patriae standing to
    bring suit against the MTBE defendants on behalf of the residents of New
    Hampshire. City of Dover, 153 N.H. at 187-88.
    The jury was not instructed that Exxon owed a duty to the State as
    sovereign. Rather, the trial court instructed:
    In deciding whether there was a design defect in the product,
    you may consider whether there was a warning, and, if so, whether
    the warning was adequate. The warning is inadequate unless it
    22
    makes the potential harmful consequences apparent and contains
    specific language directed at the significant risks or dangers
    caused by a failure to use the product in the prescribed manner.
    The manner of the warning is inadequate unless it is of such
    intensity to cause a reasonable person to exercise caution equal to
    the potential danger.
    ....
    The State has the burden to prove that if ExxonMobil had
    provided an adequate warning, MTBE gasoline would not have
    been used or would have been used differently.
    A failure to warn amounts to a legal cause of harm when the
    failure to warn is a substantial factor in bringing about the harm,
    and if the harm would not have occurred without the failure to
    warn. The failure to warn need not be the only cause of the injury,
    but it must be a substantial factor in bringing about the injury.
    We reject Exxon’s argument that the State’s failure-to-warn claim was
    improper because it was premised upon a duty to warn the “sovereign qua
    sovereign.” Accordingly, we find no error.
    VII. Market Share Liability
    Exxon argues that market share liability is not an acceptable theory of
    recovery and, that, even if it is, the trial court erred in applying market share
    liability in this case. Several years before trial, Exxon sought an order
    requiring the State to specify “which Defendants it seeks to hold liable for the
    damages,” “what damages it seeks to recover from those Defendants and when
    and how the damages occurred,” and “the legal theory for holding those
    Defendants liable for the damages.” (Quotations omitted.) The trial court
    denied the motion, finding that
    requiring the State to allege specifically which defendant caused
    each injury would create an impossible burden given the
    allegations of commingling of MTBE and the asserted indivisible
    injury to the State of New Hampshire’s water supplies. To
    mandate the State to establish more particularized causation
    would essentially allow the defendants to seek to avoid liability
    because of lack of individualized proofs where the gravamen of the
    claim is . . . that all defendants placed gasoline containing MTBE
    into the stream of commerce, thereby causing [the State’s] injury.
    To allow such a state of events would be to allow claims for
    tortious conduct for discrete, identifiable, and perhaps lesser
    23
    tortious acts, but to deny claims for tortious conduct where the
    conduct alleged may be part of group activity which is alleged [to]
    have led to a common, and more deleterious, result.
    (Quotation omitted.)
    In a subsequent order, the trial court, recognizing that “situations exist
    where a plaintiff may not necessarily be able to identify, specifically, which
    members of a group, who are engaged in the same activity, caused his or her
    damages,” noted that courts “allow plaintiffs to prove causation through
    alternative theories of liability,” including market share liability and “seemingly
    specific to the MTBE cases, . . . commingled product theory.” The court found
    that the “commingled product theory” does not apply here because that theory
    “only relieves the Plaintiff of its burden to prove the percentage of a particular
    Defendant’s gasoline found at a particular site,” and the court “has already
    found that a specific site-by-site approach is unfeasible and unnecessary in
    this case.” Accordingly, the trial court concluded that market share liability “is
    a more reasoned approach to this case.”
    As the trial court explained, the purpose behind market share liability is
    that
    [i]n our contemporary complex industrialized society, advances in
    science and technology create fungible goods which may harm
    consumers and which cannot be traced to any specific producer.
    The response of the courts can be either to adhere rigidly to prior
    doctrine, denying recovery to those injured by such products, or to
    fashion remedies to meet these changing needs. In an era of mass
    production and complex marketing methods the traditional
    standard of negligence is insufficient to govern the obligations of
    manufacturer to consumer, courts should acknowledge that some
    adaptation of the rules of causation and liability may be
    appropriate in these recurring circumstances.
    (Quotation, ellipsis, and brackets omitted.) The court noted that in
    determining whether market share liability applies in certain circumstances,
    the Restatement (Third) of Torts: Products Liability sets forth six factors that
    provide a general framework for analysis:
    (1) The generic nature of the product; (2) the long latency period of
    the harm; (3) the inability of plaintiffs to discover which
    defendant’s product caused plaintiff’s harm; (4) the clarity of the
    causal connection between the defective product and the harm
    suffered by plaintiffs; (5) the absence of other medical or
    environmental factors that could have caused or materially
    contributed to the harm; and (6) the availability of sufficient
    24
    “market share” data to support a reasonable apportionment of
    liability.
    (Quotation and ellipsis omitted.) See Restatement (Third) of Torts: Products
    Liability § 15 comment c at 233 (1998). The court found that in this case
    “these factors weigh heavily in favor of utilizing market share liability.”
    Exxon subsequently moved for summary judgment on the issue of
    causation, asserting that New Hampshire has not adopted the market share
    liability theory, and that “the theory is contrary to New Hampshire law.” The
    trial court concluded, however, that New Hampshire recognizes market share
    liability. Citing Buttrick v. Lessard, 
    110 N.H. 36
     (1969), and Trull v.
    Volkswagen of America, 
    145 N.H. 259
     (2000), the court reasoned that “[t]he
    New Hampshire Supreme Court has repeatedly expressed its willingness to
    provide plaintiffs with a less stringent burden of proof where they face a
    ‘practically impossible burden,’” and that “[g]iven this willingness, the court is
    confident that existing New Hampshire law supports the application of Market-
    Share Liability.” Dismissing as unfounded Exxon’s suggestion that market
    share liability “is synonymous with absolute liability,” the trial court explained
    that
    [e]ven where a plaintiff proceeds under a Market-Share Liability
    theory, he must prove that the defendants breached a duty to
    avoid an unreasonable risk of harm from their products . . . . The
    requirement to prove that a defendant breached his duty to avoid
    harm is a separate and distinct burden. Only after a plaintiff
    makes such a showing is he entitled to a relaxed standard for
    proving causation.
    (Quotation and citation omitted.)
    Applying the six Restatement factors, the trial court determined that
    market share liability should be applied in this case. As to the first factor, the
    generic nature of the product, the court found that the State had alleged
    sufficient facts for the court to conclude that MTBE is fungible, i.e., that it is
    interchangeable with other brands of the same product. As to the second
    factor, whether the harm caused by the product has a long latency period, the
    trial court found that the harm caused by MTBE was not latent because it
    travels faster and further than other chemicals. Thus, the court concluded
    that this factor weighs in favor of Exxon. As to the third factor, the plaintiff’s
    inability to identify which defendant caused the harm, the trial court concluded
    this factor weighs in the State’s favor because “retailers commingled gasoline in
    storage tanks at stations, so it would be impossible to determine which of the
    defendant[s’] MTBE gasoline was discharged into the environment.”
    25
    The trial court found that the fourth factor, the clarity of the causal
    connection between the defective product and harm suffered by the State,
    favors the State. The court agreed with Exxon’s general proposition that the
    gasoline market does not alone reflect the risk created and, thus, the court
    required the State “to introduce market share data as targeted as possible (e.g.
    market share data specific to RFG and non-RFG counties).” (Quotation
    omitted.) Noting that it is impossible to determine market share with
    mathematical exactitude, the court concluded that the experts’ market data
    was sufficient.
    The trial court found the fifth and sixth factors favor the State. As to the
    fifth factor, whether other medical or environmental factors could have
    contributed to the harm, the court noted that Exxon had not asserted that
    other factors contributed. As to the sixth factor, the sufficiency of the market
    data, the court found that the State’s experts had presented “enough market
    data to allow the State to proceed” on a market share liability theory.
    Following the jury verdict, Exxon moved for JNOV, arguing, in part, that,
    for five reasons, the market share liability evidence the jury considered was
    insufficient for the jury to find it liable: (1) there was no evidence that Exxon’s
    market share for MTBE gasoline was 28.94% because that figure measured all
    gasoline supplied in New Hampshire; (2) there was no evidence to support the
    jury’s finding that all gasoline containing MTBE was fungible; (3) no rational
    trier of fact could have found that the State could not trace MTBE gasoline
    back to the company that supplied it because, from 1996 to 2005, the State
    could identify the suppliers that caused its alleged harm; (4) the State failed to
    identify a substantial segment of the relevant market for gasoline containing
    MTBE because it only presented evidence as to “a snapshot of” the wholesale
    market; and (5) the State failed to establish the relevant market at the time of
    its alleged injuries. Noting that Exxon had raised, and the court had rejected,
    all of these arguments before, and because Exxon raised no new law or facts to
    support its motion, the court addressed Exxon’s arguments “only for the
    purpose of further explanation and clarification.”
    Considering Exxon’s first and fifth arguments together, the court
    determined that “the State presented sufficient evidence for a reasonable juror
    to conclude that all gasoline imported into New Hampshire was commingled
    with MTBE gasoline. From there, the jury could reasonably have assigned
    Exxon the share of the gasoline market that its supply represented.” With
    respect to Exxon’s second argument, the court concluded that there was
    “sufficient evidence from which a reasonable jury could find that MTBE
    gasoline was fungible.” As to Exxon’s third and fourth arguments, the court
    noted that the State “presented evidence through various witnesses from which
    a juror could reasonably conclude that all gasoline in New Hampshire was
    statistically likely to be commingled with MTBE to some concentration. Thus,
    it was for the jury to decide whether it would rely upon the 100 percent figure
    26
    [the State’s expert] provided, or a lower figure.” The court also observed that it
    had previously found the State’s expert qualified, and that her testimony “was
    based upon sufficient facts and data; her testimony was the product of reliable
    principles and methods; and she applied the principles and methods reliably to
    the facts of the case.” Finally, the trial court addressed Exxon’s additional
    argument that, because MTBE gasoline could be traced to a supplier from the
    refinery, the State failed to prove its market share case. The court stated:
    The State’s theory of the case, as addressed in pretrial, trial, and
    directed verdict rulings, was that MTBE gasoline is untraceable
    once spilled or leaked; once it causes harm to the State. It is
    wholly irrelevant that gasoline might be traceable to a particular
    supplier from a wholesale distributor or even the refinery because,
    as the State alleged, once the gasoline causes harm, it cannot be
    traced to a supplier, distributor, or refiner. The jury heard
    evidence to this extent, and could thereby have found that the
    State met the requisites of relying on market share liability for
    causation purposes.
    Exxon also moved to set aside the verdict and for a new trial arguing, in
    part, that the trial court erred as a matter of law by allowing the State to use
    market share liability. Exxon argued that the State “should have been
    compelled . . . to proceed on a site-specific basis and rely on traditional
    causation to prove its claims,” and that it was error “to permit the State to use
    a wholesale supplier market share when it was undisputed that . . . the MTBE
    gasoline that allegedly caused the State’s harm could be traced back to the
    wholesale suppliers, thus negating the need for or applicability of [market
    share liability] theories.” The trial court rejected Exxon’s arguments. As to
    Exxon’s argument that the jury needed to find first that the State could not
    prove traditional causation in order to find the State entitled to rely upon
    market share liability, the trial court stated that market share liability “did not
    require the State to prove that it could not establish traditional causation; it
    required the State to show that it could not identify the tortfeasor responsible
    for its injury. The ‘last resort’ requirement focuses on the inability of the
    plaintiff to identify the manufacturer of a product, not the absence of
    alternative causes of action or theories of recovery.” The court concluded:
    During trial, the State presented several witnesses who
    testified that MTBE gasoline is fungible and commingled at nearly
    every step in the distribution network, thereby making it virtually
    impossible if not impossible to trace from a spill or leak back from
    a contamination site to a retailer or supplier. This testimony
    tended to fulfill the State’s burden of proving that it was unable to
    identify the specific tortfeasor responsible for its injury. The jury’s
    verdict—finding that the State was unable to identify the specific
    27
    tortfeasor responsible for its injury—was not conclusively against
    the weight of the evidence.
    (Citations omitted.)
    On appeal, Exxon argues that the trial court erred in adopting market
    share liability in New Hampshire because it “departs from centuries of New
    Hampshire law.” Exxon also argues that “[e]ven if market share liability would
    ever be appropriate under New Hampshire law, this would be a poor case to
    make that first jump” and that the trial court “applied the wrong market
    share.” The State argues that traditional principles of tort law support the use
    of market share evidence, that Exxon has failed to show that market share
    liability was not warranted on the facts of this case, and that the trial court
    properly ruled that the jury was entitled to determine that Exxon should be
    held liable for its percentage of the supply, rather than the refining, market.
    We review challenges to a trial court’s evidentiary rulings under our
    unsustainable exercise of discretion standard and reverse only if the rulings
    are clearly untenable or unreasonable to the prejudice of a party’s case. In the
    Matter of McArdle & McArdle, 
    162 N.H. 482
    , 485 (2011). We review questions
    of law de novo. Sanderson v. Town of Candia, 
    146 N.H. 598
    , 600 (2001).
    Market share liability has its roots in a 1980 decision of the California
    Supreme Court, Sindell v. Abbott Laboratories, 
    607 P.2d 924
     (Cal. 1980). In
    Sindell, the plaintiffs alleged injuries resulting from their in utero exposure to
    the drug diethylstilbesterol (DES), a synthetic hormone that was marketed to
    women as a miscarriage preventative from 1947 to 1971. Sindell, 
    607 P.2d at 925
    . In 1971, a link was discovered between fetal exposure to DES and the
    development many years later of adenocarcinoma. 
    Id.
     Over 200
    manufacturers made DES and, because of the long latency period and generic
    nature of the drug, many plaintiffs were unable to identify the precise
    manufacturer of the DES ingested by their mothers during pregnancy. 
    Id. at 931
    . Plaintiff Sindell brought a class action against 11 drug manufacturers,
    alleging that the defendants were jointly and severally liable because they had
    acted in concert to make, market, and promote DES as a safe and effective
    drug for preventing miscarriages. 
    Id. at 925-26
    . The trial court had dismissed
    the claims due to Sindell’s inability to identify which defendants had
    manufactured the DES responsible for her injuries. 
    Id. at 926
    .
    In reversing that decision, the California Supreme Court expanded
    alternative liability to encompass what is now known as market share liability.
    Under market share liability, the burden of identification shifts to the
    defendants if the plaintiff establishes a prima facie case on every element of the
    claim except for identification of the actual tortfeasors, and the plaintiff has
    joined the manufacturers of a “substantial share” of the DES market. 
    Id. at 936-37
    . Once these elements are established, each defendant is severally
    28
    liable for the portion of the judgment that represents its share of the market at
    the time of the injury, unless it proves that it could not have made the DES
    that caused the plaintiff’s injuries. 
    Id. at 937
    .
    The court based its decision upon two considerations: (1) “as between an
    innocent plaintiff and negligent defendants, the latter should bear the cost of
    the injury”; and (2) “[f]rom a broader policy standpoint,” because the
    manufacturer “is in the best position to discover and guard against defects in
    its products and to warn of harmful effects . . . , holding it liable . . . will
    provide an incentive to product safety.” 
    Id. at 936
    . The court held it to be
    reasonable, in the context of the case, “to measure the likelihood that any of
    the defendants supplied the product which allegedly injured plaintiff by the
    percentage which the DES sold by each of them . . . bears to the entire
    production of the drug sold by all for that purpose.” 
    Id. at 937
    . By holding
    each defendant liable for the proportion of the judgment represented by its
    share of the market, “each manufacturer’s liability would approximate its
    responsibility for the injuries caused by its own products.” 
    Id.
    Several states have adopted some form of market share liability. See,
    e.g., Collins v. Eli Lilly Co., 
    342 N.W.2d 37
    , 49-51 (Wis. 1984) (adopting a form
    of market share liability in DES case); Martin v. Abbott Laboratories, 
    689 P.2d 368
    , 380-82 (Wash. 1984) (rejecting Sindell market-share theory of liability in
    favor of market-share alternative liability in DES case); Hymowitz v. Eli Lilly
    and Co., 
    539 N.E.2d 1069
    , 1075-78 (N.Y. 1989) (adopting market share liability
    theory for a national market in DES case); Conley v. Boyle Drug Co., 
    570 So. 2d 275
    , 285-86 (Fla. 1990) (adopting market share alternate liability theory in
    DES case); Smith v. Cutter Biological, Inc., 
    823 P.2d 717
    , 727-29 (Haw. 1991)
    (adopting market share liability theory in action against manufacturers of blood
    product). In other jurisdictions, courts have left open the possibility of
    adopting market share liability in the future. See, e.g., Skipworth v. Lead
    Industries Ass’n, Inc., 
    690 A.2d 169
    , 172 (Pa. 1997) (deciding not to adopt
    market share liability in lead paint case, but recognizing that the need to adopt
    that theory might arise in the future); Shackil v. Lederle Laboratories, 
    561 A.2d 511
    , 529 (N.J. 1989) (decision “should not be read as forecasting an
    inhospitable response to the theory of market-share liability in an appropriate
    context”); Case v. Fibreboard Corp., 
    743 P.2d 1062
    , 1066-67 (Okla. 1987)
    (rejecting market share liability in asbestos case but recognizing that market
    share considerations were sufficient in DES context to achieve a balance
    between the rights of the defendants and the rights of the plaintiffs); Payton v.
    Abbott Labs, 
    437 N.E.2d 171
    , 190 (Mass. 1982) (court might recognize “some
    relaxation of the traditional identification requirement in appropriate
    circumstances so as to allow recovery against a negligent defendant of that
    portion of a plaintiff’s damages which is represented by that defendant’s
    contribution of DES to the market in the relevant period of time”); see Abel v.
    Eli Lilly and Co., 
    343 N.W.2d 164
    , 173-74 (Mich. 1984) (a “new DES-unique
    version of alternative liability” will be applied in cases in which all defendants
    29
    have acted tortiously, but only one unidentifiable defendant caused plaintiff’s
    injury).
    We disagree with Exxon that the trial court erred in concluding that New
    Hampshire would recognize market share liability as an alternative liability
    theory and that the theory is proper on the facts of this case. In Buttrick v.
    Lessard we adopted strict liability for design defect claims because requiring
    the plaintiff to prove negligence would impose “an impossible burden” on the
    plaintiff due to the difficulty of proving breach of a duty by a distant
    manufacturer using mass production techniques. Buttrick, 
    110 N.H. at 39
    .
    We explained:
    The rule requiring a person injured by a defective product to
    prove the manufacturer or seller negligent was evolved when
    products were simple and the manufacturer and seller generally
    the same person. Knowledge of the then purchaser . . . was
    sufficient to enable him to not only locate the defect but to
    determine whether negligence caused the defect and if so whose.
    The purchaser of the present day is not in this position. How the
    defect in manufacture occurred is generally beyond the knowledge
    of either the injured person or the marketer or manufacturer.
    
    Id.
     As we later noted, what was crucial to our policy analysis in Buttrick “was
    the recognition that the need to establish traditional legal fault in certain
    products liability cases had proven to be, and would continue to be, a
    practically impossible burden. This was the compelling reason of policy
    without which Buttrick would have gone the other way.” Bagley v. Controlled
    Environment Corp., 
    127 N.H. 556
    , 560 (1986) (citations and quotation
    omitted).
    Based upon this rationale, we subsequently placed the burden of proving
    apportionment upon defendants in crashworthiness or enhanced injury cases
    involving indivisible injuries. Trull, 145 N.H. at 260. In Trull, we held that
    plaintiffs were required to prove that a design defect was a substantial factor in
    producing damages over and above those caused by the original impact to their
    car, and, once they had made that showing, the burden would shift to the
    defendants to show which injuries were attributable to the initial collision and
    which to the design defect. Id. at 265. That burden was placed upon the
    defendants because the plaintiffs would otherwise have been “relegated to an
    almost hopeless state of never being able to succeed against a defective
    designer.” Id. (quotation omitted). We were persuaded by policy reasons not to
    place a “practically impossible burden” upon injured plaintiffs. Id.
    By contrast, we have declined to expand products liability law in cases in
    which plaintiffs have not faced a practically impossible burden of proving
    negligence. See, e.g., Royer v. Catholic Med. Ctr., 
    144 N.H. 330
    , 335 (1999)
    30
    (strict liability did not apply to tort action against non-manufacturer hospital
    for selling defective prosthetic knee to plaintiff); Bruzga v. PMR Architects, 
    141 N.H. 756
    , 761 (1997) (unlike a consumer who purchases a mass-produced
    good, strict liability does not apply to architect and contractor because the
    owner or user of a building does not face “extraordinary difficulties in proving
    liability under traditional negligence principles”); Bagley, 127 N.H. at 560
    (declining to impose strict liability in action by landowner against adjoining
    landowner for damages resulting from soil and groundwater contamination
    because “there [was] no apparent impossibility of proving negligence”); Siciliano
    v. Capitol City Shows, Inc., 
    124 N.H. 719
    , 730 (1984) (refusing to extend strict
    liability to owner and operator of amusement park ride when there was no
    indication that the plaintiffs suffered an “unfair burden” from not doing so
    because they possess adequate protection through an action for negligence);
    Wood v. Public Serv. Co., 
    114 N.H. 182
    , 189 (1974) (no “compelling reason of
    policy or logic” advanced to apply strict liability to electric companies in
    wrongful death action).
    We have also declined to expand products liability law when the
    defendants could not have been at fault. Simoneau v. South Bend Lathe, Inc.,
    
    130 N.H. 466
     (1988). In Simoneau, we rejected the product line theory of
    successor liability, reasoning that “liability without negligence is not liability
    without fault.” 
    Id. at 469
    . Under the product line theory, a party that acquires
    a manufacturing business and continues the output of its line of products,
    assumes strict liability for defects in units of the same product line
    manufactured and sold by the predecessor company. 
    Id. at 468
    . We refused to
    “impose what amounts to absolute liability on a manufacturer,” 
    id. at 470
    ,
    reaffirming “[t]he common-law principle that fault and responsibility are
    elements of our legal system applicable to corporations and individuals alike”
    and that such principle ought “not be undermined or abolished by spreading of
    risk and cost in this State.” 
    Id. at 469
     (quotation omitted).
    Based upon the reasoning expressed in our cases developing products
    liability law in New Hampshire, the trial court concluded that it would “not
    rigidly apply theories of tort law where doing so would either be impractical or
    unfairly ‘tilt the scales’ in favor of one party or another.” We agree with the
    trial court that, based upon our willingness to construct judicial remedies for
    plaintiffs who would be left without recourse due to impossible burdens of
    proof, applying market share liability was justified in the circumstances
    presented by this case. In addition to finding that the State had proven all of
    the elements of its claims, the jury found: “MTBE gasoline is fungible”; the
    State “cannot trace MTBE gasoline found in groundwater and in drinking water
    back to the company that manufactured or supplied that MTBE gasoline”; and
    the State “has identified a substantial segment of the relevant market for
    gasoline containing MTBE.” We have reviewed the record and conclude that it
    contains sufficient evidence to support the jury’s findings. Given the evidence
    presented, the State faced an impossible burden of proving which of several
    31
    MTBE gasoline producers caused New Hampshire’s groundwater
    contamination. We hold that the trial court did not unsustainably exercise its
    discretion in allowing the State to use the theory of market share liability to
    determine the portion of the State’s damages caused by Exxon’s conduct.
    Exxon argues that because the trial court found that there was sufficient
    evidence for the State to prove traditional causation, it erred by instructing the
    jury on market share liability. We disagree. To the contrary, the trial court
    merely found that the State could prove “but for” causation as required under
    the market share liability theory. “Under market share liability, the burden of
    identification shifts to the defendants if the plaintiff establishes a prima facie
    case on every element of the claim except for identification of the actual
    tortfeasor or tortfeasors . . . .” In re Methyl Tertiary Butyl Ether Products Liab.,
    
    379 F. Supp. 2d 348
    , 375 (S.D.N.Y. 2005). Exxon argued in its motion for a
    directed verdict at the close of the State’s case-in-chief that, “[f]or each of the
    State’s claims, the State was required to provide evidence specific to
    ExxonMobil that gasoline containing MTBE from ExxonMobil was the but for
    cause of the State’s alleged injuries and that ExxonMobil’s conduct or product
    were a substantial factor in bringing about the State’s alleged injuries.” Exxon
    asserted that such proof “was utterly lacking . . . and the State has not
    identified any evidence that gasoline containing MTBE from ExxonMobil caused
    any of the alleged contamination in this case under traditional theories of
    causation.”
    The trial court denied Exxon’s motion, reasoning that, from testimony
    presented by the State, “a reasonable jury could conclude that Exxon was the
    proximate cause of the State’s alleged injury under a traditional causation
    theory.” Thus, the trial court rejected Exxon’s argument that the State had not
    established a prima facie case on each of its claims. Further, the evidence
    established that MTBE gasoline is a fungible product, that the fungibility of
    MTBE gasoline allows it to be commingled at nearly every step of the gasoline
    distribution system, and that commingling prevents the State from tracing a
    molecule of MTBE gasoline from the refinery to New Hampshire so that the
    State cannot identify the refiner of the MTBE gasoline that caused the harm.
    Thus, because the State could not identify the tortfeasor responsible for its
    injury, under market share liability the burden of identification shifted to
    Exxon. Accordingly, the jury was instructed:
    If the State has been harmed by a product that was
    manufactured and sold by any number of manufacturers and
    suppliers, and the State has no reasonable means to prove which
    manufacturer or supplier supplied the product that caused the
    injury, then the State may use market share liability to satisfy its
    burden of proof. Under market share liability, ExxonMobil is
    responsible for the State’s harm in proportion to ExxonMobil’s
    32
    share of the market for the defective product during the time that
    the State’s harm occurred.
    Market share liability requires that the State . . . prove all
    the elements for negligence, or strict liability defect in design, or
    strict liability based on a failure to warn and that the State
    suffered harm. In addition, the State must prove the following: (1)
    it has identified enough MTBE gasoline manufacturers or suppliers
    in this case so that a substantial share of the relevant market is
    accounted for; and (2) MTBE gasoline is fungible, meaning that one
    manufacturer’s or supplier’s MTBE gasoline is interchangeable
    with another’s; and (3) the State cannot identify the manufacturer
    or supplier of the MTBE gasoline that caused the harm.
    Finally, we find no error with the trial court’s ruling that the jury was
    entitled to determine that Exxon could be held liable for its percentage of the
    supply market. As the trial court reasoned, because Exxon “had or should
    have had knowledge of the characteristics of MTBE gasoline from [its] refining
    role[ ],” a jury could find Exxon liable for MTBE gasoline it supplied but did not
    refine. The trial court explained that the jury was entitled to estimates of
    supplier and refiner market share and that both reflected Exxon’s “creation of
    the risk within the State,” and that “[a]ny figure within this spectrum would be
    an appropriate measure of the State’s damages.”
    VIII. Aggregate Statistical Evidence
    Exxon argues that the State should not have been permitted to rely upon
    aggregate statistical evidence rather than individualized evidence of particular
    water supplies and sites. Before trial, Exxon moved to exclude the opinions of
    three of the State’s experts estimating the probability of MTBE occurrence in
    New Hampshire, the past costs of MTBE remediation, and the future costs of
    investigating and remediating MTBE sites. Exxon argued that these experts,
    Dr. Graham Fogg, Gary Beckett, and Dr. Ian Hutchison, “attempt to draw
    statewide conclusions about MTBE detections and costs from small ‘sample’
    datasets, extrapolating to the State at large,” but “fail . . . to follow basic, well-
    accepted statistical and scientific principles.”
    Following a hearing, the trial court issued a written order “accept[ing] the
    [State’s] argument that using statistical methods is appropriate and, as a
    result, the state-wide proof model is acceptable and relevant.” The court
    reasoned that “the use of statistical methods, assuming their reliability, makes
    the existence of the [State’s] injury more probable than it would be without
    such evidence; likewise, it will assist the trier of fact to understand and
    determine both the existence and extent of the [State’s] injury.” Thus, the trial
    court concluded that the State’s experts’ opinions “are relevant to prove injury-
    33
    in-fact and damages” and that it would accept proof of injury “through the use
    of statistical evidence and extrapolation, i.e. the ‘state-wide approach.’”
    The trial court set forth several reasons in support of its conclusion.
    First, the court noted that the majority of the cases cited by Exxon are class-
    action cases, “which disallow the use of aggregate damages across a class of
    plaintiffs.” The court found those cases distinguishable because, here, the
    State “does not seek to establish injury among several class plaintiffs through
    the use of an aggregate model, but instead seeks to prove its own injury
    through the use of statistics.” Second, the court reasoned that New
    Hampshire’s “‘declaration of policy’ confirms that an injury to both public and
    private waters within the [s]tate is an indivisible injury, allowing for the State to
    prove its claim upon state-wide proof.” The court stated that under RSA 481:1,
    “[t]he state as trustee of the waters for the public benefit declares that it has
    the authority and responsibility to provide careful stewardship over all the
    waters lying within its boundaries,” and that this statute provides the State
    “with more than just a vehicle to demonstrate standing: the statute allows the
    [State] to prove injury to a single resource.” (Quotation and brackets omitted.)
    Finally, the trial court reasoned that “general policy considerations support
    allowing the [State] to establish injury and damages using statistical methods.”
    The court stated:
    American manufacturers now mass produce goods for
    consumption by millions using new chemical compounds and
    processes, creating the potential for mass injury. As a result,
    modern adjudicatory tools must be adopted to allow the fair,
    efficient, effective and responsive resolution of claims of these
    injured masses. In a perfect setting, the [State] would have the
    resources to test each individual well over a long period of time and
    precisely determine its damages. However, if such a process were
    undertaken here, it would have to continue beyond all lives in
    being. The Court simply cannot support such a process.
    Moreover, requiring the [State] to test each individual well
    undoubtedly and unfairly “tilts the scales” in [Exxon’s] favor . . . .
    Here, . . . the necessary additional litigation costs the [State] would
    have to bear would consume much of any recovery, making
    continued pursuit of the litigation fruitless. Because of these
    public policy interests, the Court finds that allowing the [State] to
    use statistical methods of proof is relevant to prove injury and
    damages in this case.
    The fact is that for decades, judges, lawyers, jurors, and
    litigants have shown themselves competent to sift through
    statistical evidence in a variety of contexts, from mass toxic torts to
    single-car collisions. Not only have they shown themselves
    34
    competent, but also such evidence has become a generally
    accepted method for a plaintiff to prove his case. This Court is
    simply not persuaded by [Exxon’s] attempt to frame this case as a
    class action. As a result, the Court rejects the notion that New
    Hampshire law forbids the use of a statistical approach to prove
    injury-in-fact.
    (Quotations, citations, brackets, and ellipsis omitted.)
    Exxon subsequently attempted to exclude the opinions of the same three
    experts on grounds of reliability, arguing that the State’s experts used improper
    methodologies and, even when they used proper methodologies, they applied
    the methodologies incorrectly to the facts and data provided. After conducting
    a thorough analysis of each of the statistical methods employed by the State’s
    experts, the trial court concluded that their opinions and methodologies were
    reliable and denied Exxon’s motion.
    Following the trial court’s ruling that the statewide approach was
    acceptable, Exxon sought an interlocutory transfer to this court. The trial
    court denied the request, finding that Exxon failed to satisfy the requirements
    of New Hampshire Supreme Court Rule 8(1). See Sup. Ct. R. 8 (interlocutory
    appeal from ruling). In its order, the trial court noted that, despite its rulings
    otherwise, Exxon continued to assert that it is feasible to try this case on a
    well-by-well approach. As the court explained, under Exxon’s approach,
    the State would identify a contaminated drinking-water well and
    then trace the source of contamination to a particular physical
    location that leached gasoline into the ground. These locations will
    usually be businesses associated with gasoline, like retail gas
    stations and junkyards. From here, these entities can then trace
    the gasoline back through the product chain to the wholesaler and
    eventually the refiner. In this way, either the State or the retailers
    can spread the liability throughout the product chain. [Exxon]
    explain[s] that because all entities in a product chain would be
    liable for the State’s harm, the State should be required to proceed
    on a well-by-well approach.
    The trial court found this method to be “technically and scientifically
    infeasible.” The court reasoned:
    The State’s case attempts to impose liability on
    manufacturers and refiners. Without decision makers selecting,
    marketing, and reformulating MTBE, it would never have been
    included in the RFG program and would never have been imported
    into New Hampshire to spill, leak, and evaporate. Gasoline
    imported into New Hampshire would not have been capable of
    35
    contaminating the State’s water resources in the vast, seemingly
    uncontainable way it has if it did not contain MTBE. The State
    has chosen to pursue the named Defendants because they created
    the initial risk that led to widespread contamination. Based on
    this selected class of defendants, product tracing is virtually
    impossible.
    Defendants themselves admit that tracing MTBE found in a
    contaminated well all the way back to the refiner is virtually
    impossible because MTBE lacks a chemical signature, linking it to
    a particular refiner. Additionally, a contaminated well, many
    times, cannot be traced to a particular retailer, making it
    practically impossible to trace MTBE to a specific wholesaler.
    Following the jury verdict, Exxon argued in its motion to set aside the
    verdict that the statewide approach allowed the State “to prove its private well
    and ‘future injury’ case using statistical extrapolations from experts about
    potential hypothetical impacts rather than particularized evidence of an actual
    injury” and that this “resulted in the State being able to avoid its burden to
    prove individualized causation with respect to particular private well impacts.”
    The trial court denied the motion, stating that its prior rulings on this issue
    were rulings of law and that because “Exxon does not raise any new facts
    regarding these rulings and it does not contend that the jury’s verdict was
    conclusively against the weight of the evidence,” the argument “did not properly
    fall within the purview” of a motion to set aside.
    On appeal, Exxon argues that the trial court erred in allowing the State
    to prove its case on a statewide basis. Exxon asserts that “[e]very other court
    to address the issue has recognized that MTBE tort cases depend
    overwhelmingly on individualized questions of law and fact, and thus are not
    amenable to proof on a mass basis.” According to Exxon, the trial court “broke
    from these precedents” in allowing statewide aggregate evidence. The State
    argues that the “immense scope of Exxon’s pollution” has “directly affected a
    substantial portion of the State’s population” and that “[t]he statewide nature
    of Exxon’s tortious conduct, therefore, required adjudication on a statewide
    basis.” (Quotation omitted.) The State asserts that Exxon has
    “mischaracterize[d] both the trial record and the relevant standards of review.”
    We review challenges to a trial court’s evidentiary rulings under our
    unsustainable exercise of discretion standard and reverse only if the rulings
    are clearly untenable or unreasonable to the prejudice of a party’s case. In the
    Matter of McArdle, 162 N.H. at 485.
    Exxon cites In re Methyl Tertiary Butyl Ether Products Litigation, 
    209 F.R.D. 323
     (S.D.N.Y. 2002), as an example of why “MTBE tort cases depend
    overwhelmingly on individualized questions of law and fact.” The trial court,
    36
    however, found this and other MTBE cases involving a determination as to
    “injury in fact” to be unhelpful, as “the facts of this case are very different.” In
    contrast to the New York MTBE case in which the court dismissed full
    categories of class plaintiffs who had actually tested and detected no MTBE in
    their wells, the trial court noted that here, “the [State] has tested many wells
    where it has discovered the existence of MTBE. It merely seeks to extrapolate
    that information in order to establish further injury.” The trial court agreed
    that “if the [State] had not tested any wells or had tested wells and found no
    MTBE, the [State’s] pursuit of a statistical approach would be fruitless.” As
    further distinguishing the New York MTBE case, the trial court noted that,
    whereas in the New York case, the plaintiffs’ allegations neither contained any
    statistics pertaining to MTBE detection rates for private wells nor established
    that the private wells were located in proximity to possible release sites, here
    the State “provided the Court with adequate statistical evidence through their
    experts,” and, the State seeks recovery “on the basis of ‘high-risk’ areas only.”
    At trial, the State offered proof based upon expert testimony regarding
    1,584 specific sites where MTBE has been known to leak and has
    contaminated the subsurface. The State also introduced scientific evidence
    through expert testimony that 5,590 drinking water wells serving 16,276
    people are contaminated with MTBE at levels over 13 ppb, and that many more
    are expected to become contaminated in the future. Dr. Fogg used substantial
    data on MTBE contamination in the state to calculate statistically the number
    of drinking wells currently contaminated by MTBE. The State’s experts
    expressly accounted for the fact that “every site is different.” Exxon does not
    contend on appeal that the expert evidence was irrelevant or unreliable.
    Based upon the record, we conclude that the trial court’s determination
    that the use of statistical evidence and extrapolation to prove injury-in-fact was
    not an unsustainable exercise of discretion. See Bodwell v. Brooks, 
    141 N.H. 508
    , 510-11 (1996) (statistical probability evidence may be used to rebut the
    presumption of legitimacy); Rancourt v. Town of Barnstead, 
    129 N.H. 45
    , 50-51
    (1986) (validity of a town’s growth control ordinance rests upon a relationship
    between the town’s growth restrictions and a projection of “normal growth”
    based upon scientific and statistical evidence); In re Neurontin Marketing and
    Sales Practices, 
    712 F.3d 21
    , 42 (1st Cir. 2013) (“courts have long permitted
    parties to use statistical data to establish causal relationships”).
    IX. RSA 507:7-e and DeBenedetto
    Exxon argues that it was “unfairly prejudiced in its ability to present its
    defense” under RSA 507:7-e (2010) and DeBenedetto v. CLD Consulting
    Engineers, Inc., 
    153 N.H. 793
     (2006). Before trial, Exxon filed disclosures
    containing lists of several thousand non-litigants, including the names of
    gasoline suppliers, gasoline importers, foreign refiners, domestic refiners,
    distributors, trucking companies, and persons with leaking underground
    37
    storage tanks. After reviewing these initial disclosures, the trial court found
    that they did not sufficiently allege fault against the non-litigants and, as a
    result, did not provide either the court or the State with adequate notice under
    DeBenedetto. The trial court ordered Exxon to “set forth, with specificity, a
    good faith basis for why each party listed within their disclosures is responsible
    for the claims made by the State.”
    The State subsequently moved to strike Exxon’s supplemental
    disclosures, maintaining that Exxon failed to comply with the trial court’s order
    because the disclosures did not provide sufficient evidence specific to each
    DeBenedetto party. In its order, the trial court stated:
    Despite the fact that the New Hampshire Supreme Court has
    never directly addressed the present DeBenedetto issues, it has,
    nonetheless, supplied a framework to guide this court’s analysis.
    This framework is made up of four principles: first, that RSA
    507:7-e applies to all parties contributing to the occurrence giving
    rise to the action, including those immune from liability or
    otherwise not before the court; second, that a civil defendant who
    seeks to deflect fault by apportionment to non-litigants is raising
    something in the nature of an affirmative defense; third, the
    defendant carries the burdens of production and persuasion; and
    fourth, that a defendant may not easily shift fault under RSA
    507:7-e; allegations of a non-litigant tortfeasor’s fault must be
    supported by adequate evidence before a jury or court may
    consider it for fault apportionment purposes.
    (Quotations and citations omitted.)
    The trial court found “the most notable portion of the framework, and the
    most helpful in the present analysis, is that portion identifying non-litigant
    liability as akin to an ‘affirmative defense.’” Because in New Hampshire
    defendants are required to plead affirmative defenses to provide the plaintiff
    with adequate notice of the defense and a fair opportunity to rebut it, the trial
    court determined that “when a defendant raises a defense under DeBenedetto,
    its disclosure must provide the plaintiff with adequate notice of the defense and
    the plaintiff must be given fair opportunity to rebut it.” Looking at the
    requirements of other jurisdictions, the court reasoned that the Colorado
    standard “for evaluating a defendant’s notice of non-litigant fault [is]
    persuasive in molding a standard for ‘adequate notice’ under DeBenedetto.”
    Thus, the court concluded that
    proper notice in the DeBenedetto context requires [Exxon] to
    provide to the State identifying information for the nonparty in
    addition to a brief statement of the basis for believing such
    nonparty to be at fault. Furthermore, the notice must allege
    38
    sufficient facts to satisfy all the elements of at least one of the
    State’s claims.
    (Quotations, citations, and brackets omitted.) The trial court rejected Exxon’s
    assertion that it need demonstrate only “how a DeBenedetto party contributed
    to the harm alleged by the State, not correspond each DeBenedetto party to
    individual claims,” reasoning that Exxon cannot assert that it has “any less of
    a burden than to link [its] own allegations of non-litigant fault to at least one of
    the claims asserted by the State.” (Quotation omitted.)
    Thereafter, the trial court determined that with respect to negligence,
    Exxon “must assert that a nonparty owed a duty with respect to MTBE gasoline
    and breached that duty. This will require demonstrating that a nonparty had
    some knowledge of MTBE or its characteristics, or should have had some
    knowledge.” With respect to products liability, the trial court determined that
    Exxon “must assert that a nonparty knew or reasonably should have known of
    the nature of MTBE upon which the State’s claims are based in order to show
    that an entity below [Exxon] in the product chain is similarly culpable and/or
    owed a similar duty to warn.” The trial court explained that Exxon “need not
    show that a nonparty was aware of the unique nature of MTBE . . . However, a
    nonparty cannot possibly [have] foreseen the type of harm alleged by the State
    absent some knowledge that MTBE was generally present in gasoline or could
    have been present. Alternatively, [Exxon] may demonstrate that a nonparty
    should have known of MTBE.”
    After the jury verdict, Exxon moved to set aside the verdict and for a new
    trial. Exxon argued that the trial court erred by: (1) “improperly requiring
    ExxonMobil to prove that the non-parties were liable for the State’s claims,
    rather than proving only that they contributed to the State’s injury”; (2)
    “preventing ExxonMobil from relying on RSA 146-A to establish the non-
    parties’ fault”; (3) “requiring proof that the non-parties had actual or
    constructive knowledge of MTBE’s presence in gasoline before contributing to
    the State’s injury”; and (4) requiring it to present “categories of evidence rather
    than evidence about the actions of particular individuals in connection with
    particular injuries.”
    The trial court rejected Exxon’s first three challenges because they raised
    pure questions of law that the court addressed pretrial and “Exxon has raised
    no new fact or law to convince the Court to readdress these arguments.”
    Regarding the statewide proof claim, the trial court agreed with the State that
    allowing categories was a convenience, not a requirement, and “Exxon could
    have presented evidence regarding every individual DeBenedetto party, as
    opposed to categorical evidence.” As to the categories, the trial court found
    that “Exxon presented very little evidence establishing nonparty liability” and
    that its primary witness who testified regarding the various categories of
    nonparties “did not indicate that nonparties were aware of MTBE’s presence in
    39
    gasoline during the relevant time period, and he never stated that nonparties
    were aware their actions caused spills and leaks that caused MTBE
    contamination.” Accordingly, the trial court concluded that it “cannot say that
    a jury verdict rejecting Exxon’s DeBenedetto defense was conclusively against
    the weight of the evidence.”
    On appeal, Exxon argues that the trial court’s DeBenedetto rulings
    “deviate from clear precedent and denied Exxon a meaningful opportunity to
    prove that third parties contributed to at least part of the alleged harm.”
    Exxon asserts that the trial court’s ruling that Exxon had to link each
    DeBenedetto party to a claim made by the State “eviscerated Exxon’s statutory
    right to allocate fault to third parties.” The State argues that Exxon’s
    DeBenedetto argument is “unavailing because Exxon did not show at trial that
    non-parties were at fault for MTBE pollution.”
    We review challenges to a trial court’s evidentiary rulings under our
    unsustainable exercise of discretion standard and reverse only if the rulings
    are clearly untenable or unreasonable to the prejudice of a party’s case. In the
    Matter of McArdle, 162 N.H. at 485. We review questions of law de novo.
    Sanderson, 146 N.H. at 600.
    Pursuant to RSA 507:7-e and DeBenedetto, defendants may ask a jury to
    shift or apportion fault from themselves to other nonparties in a case. RSA
    507:7-e, I, provides:
    I. In all actions, the court shall:
    (a) Instruct the jury to determine . . . the amount of damages to
    be awarded to each claimant and against each defendant in
    accordance with the proportionate fault of each of the parties; and
    (b) Enter judgment against each party liable on the basis of the
    rules of joint and several liability, except that if any party shall be
    less than 50 percent at fault, then that party’s liability shall be
    several and not joint and he shall be liable only for the damages
    attributable to him.
    “[F]or apportionment purposes under RSA 507:7-e, the word ‘party’ refers
    not only to ‘parties to an action, including settling parties,’ but to all parties
    contributing to the occurrence giving rise to an action, including those immune
    from liability or otherwise not before the court.” DeBenedetto, 153 N.H. at 804
    (quotation, ellipsis, and citation omitted). “[A] defendant may not easily shift
    fault under RSA 507:7-e; allegations of a non-litigant tortfeasor’s fault must be
    supported by adequate evidence before a jury or court may consider it for fault
    apportionment purposes.” Id. “[A] civil defendant who seeks to deflect fault by
    apportionment to non-litigants is raising something in the nature of an
    40
    affirmative defense.” Goudreault v. Kleeman, 
    158 N.H. 236
    , 256 (2009).
    Accordingly, “the defendant carries the burdens of production and persuasion.”
    
    Id.
     Furthermore, “a defendant who raises a non-litigant apportionment defense
    essentially becomes another plaintiff who must seek to impose liability on a
    non-litigant just as a plaintiff seeks to impose it on him.” 
    Id.
     (quotation and
    brackets omitted); see Wyle v. Lees, 
    162 N.H. 406
    , 413 (2011) (trial court
    implicitly concluded that the defendants failed to prove their allegations of
    comparative negligence for purposes of apportionment of damages).
    As the trial court correctly concluded, apportionment under RSA 507:7-e
    requires proof of fault. DeBenedetto, 153 N.H. at 800 (apportionment must
    include all tortfeasors who are causally negligent by either causing or
    contributing to the occurrence in question). At trial, Exxon’s expert witness,
    Jeffrey A. Klaiber, an environmental consultant, testified for several days,
    including providing extensive testimony regarding typical spill and leak
    scenarios for the various categories of alleged faulty nonparties. He
    acknowledged, however, that he did not interview anyone at any of the sites
    that Exxon contends are responsible for MTBE contamination, that he did not
    know whether anyone who owned or operated any of those sites knew that
    MTBE gasoline behaves differently from other gasolines when released into the
    environment, and that he did not know if any of the owners or operators of
    those sites even knew that MTBE was in the gasoline that they were receiving.
    Nonetheless, the trial court allowed the jury to consider apportioning liability to
    those nonparties. The trial court instructed the jury:
    In this state, courts and juries may apportion fault to all
    persons or entities who contributed to causing an injury, even if
    they are not parties to the lawsuit. What that means in this case
    is that if you find that the State has proven any of its three claims
    against ExxonMobil, then ExxonMobil shall have the burden of
    proving that some or all of its fault should be allocated to the
    nonparties identified in Defense Exhibit 1047.
    The jury answered “No” to each portion of this question on the special verdict
    form: “Has ExxonMobil proven, by a preponderance of the evidence, that some
    or all of its fault should be allocated to nonparties in the following categories?
    . . . a. Tanks With Holes . . . b. Aboveground Releases . . . c. Tanks With
    Releases . . . d. Junkyards.” Based upon the record, we are not persuaded by
    Exxon’s argument that it was denied “a meaningful opportunity” to apportion
    fault to third parties or that it suffered any prejudice from the trial court’s
    rulings. Accordingly, we find no error.
    X. Parens Patriae
    Exxon argues that the trial court erroneously decided that the State had
    parens patriae standing, rather than submitting this question to the jury.
    41
    Exxon asserts that whether there is an injury to a “substantial segment” of the
    population is a question of fact for the jury, not a question of law for the judge,
    and that a rational jury could have found the State’s proof insufficient. The
    State argues that Exxon waived this argument because Exxon failed to raise it
    before the trial court, including failing to raise it in its motion for summary
    judgment on parens patriae issues or in its motion for a directed verdict, and
    failed to argue it in either its motion for JNOV or motion to set aside the
    verdict.
    We have reviewed the record and agree with the State that Exxon has
    failed to demonstrate that it specifically raised this argument before the trial
    court. See Dukette, 166 N.H. at 255. Accordingly, because the argument is
    not preserved for our review, we decline to address it substantively. See N.
    Country Envtl. Servs., 150 N.H. at 619.
    XI. Future Well Impacts
    Exxon argues that the State’s “future, speculative, and unknown well
    and site impacts” are not ripe for review. Before trial, Exxon raised this
    argument in a summary judgment motion. The trial court denied the motion,
    stating:
    It is well settled in New Hampshire that an injured party may
    seek recovery for future harm that will arise from a current injury.
    In order to recover for future damages, a party need only show that
    there is evidence from which it can be found to be more probable
    than not that the future damages will occur. Thus, contrary to
    [Exxon’s] argument, New Hampshire has no absolute prohibition
    on awarding future damages.
    The court finds that the State’s damages for future and
    unknown well impacts are fit for . . . judicial determination.
    Importantly, the injury causing the future harm has already
    occurred. The injury occurred when MTBE entered State waters.
    The State’s claim for future damages merely seeks to measure the
    extent of the harm caused, which New Hampshire allows.
    Furthermore, the court has already determined that the methods
    undertaken by the State’s experts for determining the future harm
    . . . are relevant and reliable. Therefore, the State’s future
    damages claims are ripe for review under the first prong of the
    ripeness test.
    (Quotation, citations, and brackets omitted.)
    Exxon moved for a directed verdict following the State’s conclusion of its
    case-in-chief arguing, in part, that the State failed to present its damages
    42
    figure with sufficient certainty. Exxon argued that the State failed to prove that
    it has “sustained a cognizable injury” and that the State’s damages evidence
    was insufficient. The trial court rejected the motion, stating:
    The State need only show an approximation of its harm. As
    this Court’s prior orders on this issue explain, the State does not
    need to have identified every contaminated well in New Hampshire
    to show it is injured. Nonetheless, the State presented testimony
    in its case-in-chief through Gary Beckett, Dr. Ian Hutchison, Dr.
    Graham Fogg, Steve Guercia, and Brandon Kernen. These
    witnesses estimated the number of wells that are currently
    suffering contamination based on statistical sampling, the location
    of spill sites, and the number and proximity of drinking wells in
    New Hampshire. The mere fact that the State’s damages figure is
    based on an approximation does not make it speculative or legally
    insufficient. Further, the evidence presented during the State’s
    case-in-chief regarding the estimated costs of remediation efforts
    based on estimated contamination is sufficient for a reasonable
    juror to conclude the State has suffered a cognizable injury.
    (Citation omitted.)
    Following the jury verdict Exxon moved for JNOV, arguing that “several
    aspects of the jury’s damages award for future well testing and treatment . . .
    are unsupported by the evidence.” Denying the motion, the trial court stated:
    Exxon explains that even if it is liable, the damages figure the jury
    awarded is speculative because it is based on expert estimations
    and not supported by evidence; it is not sufficiently definite. The
    Court considered and rejected this argument in its directed verdict
    order: “The mere fact that the State’s damages figure is based on
    an approximation does not make it speculative or legally
    insufficient.” Because Exxon raises no new facts or law, the Court
    will not reconsider its prior ruling. As such, the record is not so
    clearly in Exxon’s favor that the Court can find the jury’s verdict is
    unsustainable.
    (Citation omitted.)
    In addition, Exxon moved to set aside the verdict and for a new trial,
    arguing that “[j]ust because MTBE is in groundwater now does not mean that it
    will injure private wells in the future,” and, therefore, “these projected injuries
    are speculative and were not ripe.” The trial court rejected Exxon’s argument,
    stating:
    43
    This Court has ruled that the State’s injury already
    occurred; MTBE has already been brought into New Hampshire.
    Exxon sought a jury instruction on imminent and immediate
    harm, which the Court denied. Whether the State has been
    injured is a question for the jury, but prospective damages are
    proper where there was evidence from which the jury could find it
    more probable than otherwise that such damage would occur.
    Because Exxon’s motion raises no new issues of law or fact, the
    Court declines to reconsider its prior rulings.
    (Quotation and citations omitted.)
    On appeal, Exxon argues that the trial court erred “in allowing the State
    to claim more than $300 million in damages for the costs of testing private
    wells for possible MTBE contamination, $150 million to treat whatever
    contamination is found in the wells in the future, and another $218 million for
    anticipated generalized costs to characterize . . . and clean up release sites,”
    because these claims are unripe and should be dismissed. Exxon asserts that
    the State “did not present proof of actual or imminent contamination to
    particular private wells,” and that the State’s claims for treatment of future
    private-well impacts “are even more uncertain, remote, and contingent.”
    According to Exxon, the trial court’s ruling “dramatically increased the scope of
    this suit and took the [court] into territory where no common law court has
    gone before.”
    The State argues that its harm “exists today, and recompense for this
    type of harm is certainly no less recoverable than future medical expenses or
    damages for loss of income, both of which are regularly awarded in tort actions
    without raising ripeness concerns.” The State also asserts that its testing and
    future-treatment claims are ripe because the State “presented concrete
    evidence of damage that already has occurred.”
    “[R]ipeness relates to the degree to which the defined issues in a case are
    based on actual facts and are capable of being adjudicated on an adequately
    developed record.” Appeal of City of Concord, 
    161 N.H. 344
    , 354 (2011).
    Although we have not adopted a formal test for ripeness, we have found
    “persuasive the two-pronged analysis used by other jurisdictions that evaluates
    the fitness of the issue for judicial determination and the hardship to the
    parties if the court declines to consider the issue.” Appeal of State Employees’
    Assoc., 
    142 N.H. 874
    , 878 (1998).
    We find no error in the trial court’s rulings on this issue. The State’s
    claims for future testing and treatment are fit for judicial determination as the
    harm from MTBE has already occurred. Cf. In re Methyl Tertiary Butyl Ether
    (“MTBE”) Prod., 
    175 F. Supp. 2d 593
    , 607-11 (S.D.N.Y. 2001) (individual
    plaintiffs could not show a present threat of imminent harm because either
    44
    they had not tested their private wells or tests did not detect MTBE in their
    wells). The record establishes that, as of the time of trial, over 1,000 drinking
    wells in the state had tested positive for MTBE, and, of those, 358 wells were
    contaminated at levels over the maximum contaminant level of 13 ppb. The
    record also establishes that more than 5,000 wells, which have not yet been
    tested, were likely already contaminated with MTBE above 13 ppb at the time
    of trial. The record also contains evidence that the damage from MTBE
    contamination is not limited to drinking wells. According to the State’s experts,
    MTBE has a “residence time” of up to 50 years, during which time it gradually
    seeps through subsurface zones toward wells, lakes, and wetlands. The State’s
    experts testified that, although leaks from some underground storage tanks
    might not yet have been detected, those leaks “will continue to pose a hazard to
    groundwater quality.” As the jury was instructed:
    The State is entitled to be fully compensated for the harm resulting
    from ExxonMobil’s legal fault.
    ....
    In determining the amount of damages to allow the State,
    you may . . . . consider whether it is more probable than otherwise
    that its damages will continue into the future as a direct, natural
    and probable consequence of ExxonMobil’s legal fault and, if so,
    award it full, fair, and adequate compensation for those future
    damages.
    Exxon does not present any argument on the hardship prong of the
    ripeness test, and we therefore consider any argument regarding that prong to
    be waived. See State v. Roy, 
    167 N.H. 276
    , 286 (2015).
    XII. Prejudgment Interest
    Exxon argues that the trial court should not have awarded prejudgment
    interest on future costs. Following the jury verdict, the State moved for
    taxation of costs, including prejudgment interest pursuant to RSA 524:1-b
    (2007). Exxon moved to preclude the addition of prejudgment interest on the
    future costs portion of the State’s damage award, arguing that such an award
    would not serve the statute’s purpose and “would amount to an illegal punitive
    award.” Exxon asserted that because money has time value, interest is added
    to damages for past harms to take into account the time during which the
    plaintiff was deprived of its use, but “[t]hat rationale is inapposite to an award
    for future costs associated with establishing investigation, testing and
    treatment programs and with MTBE impacts that have not yet occurred.” The
    State objected, arguing that because the injury has already occurred when
    MTBE entered New Hampshire’s waters, Exxon’s “motion fails in its basic
    premise; there are no future injuries here.” The State also argued that even
    45
    assuming future injuries were at issue, the statute “does not distinguish
    between past and future costs or harm.”
    The trial court rejected Exxon’s arguments, noting that, although during
    trial, “the State categorized its damages as past, current, and future for
    purposes of breaking the figure into parts for evidentiary presentation, . . . this
    presentation was not intended to and did not define the State’s injury.” The
    court reasoned:
    The State presented substantial evidence that the damage to
    its waters had already been done, MTBE had already been
    imported into the State, and this is the presentation of evidence
    that the jury accepted by its verdict. The mere fact that the State
    characterized part of its damages figure as that for future testing
    and remediation does not mean that it did not suffer the loss of
    use of these monies prior to the jury’s verdict in this case.
    Further, had these monies been available during the last decade
    when litigation was pending, arguably, the cost to test and
    remediate would be lesser now.
    On appeal, Exxon argues that the trial court erred “by awarding
    prejudgment interest on the total judgment amount, or $236,372,664, when
    $195,243,134 of those damages . . . were for the State’s claims for
    investigating, testing, characterizing, and treating alleged MTBE contamination
    in New Hampshire’s private wells and future costs for site investigation and
    remediation.” According to Exxon, “[p]rejudgment interest on those future
    costs fails to serve the compensatory purpose of RSA 524:1-b and thus should
    not have been awarded.” The State argues that Exxon “makes no effort to
    square its argument with [the statute’s] text,” and that “RSA 524:1-b has dual
    purposes: to accelerate settlement and provide compensation for the loss of
    use of money damages.” (Quotation and emphasis omitted.) The State asserts
    that “[a]warding prejudgment interest to all of the State’s damages satisfies the
    objective of accelerating settlement, regardless of when the money underlying
    the damages is spent,” and that “because the contamination occurred in the
    past, ongoing treatment and testing does not, as Exxon claims, represent
    ‘future harms’ or damages the State has yet to incur.” (Quotation, brackets,
    and citation omitted.)
    “Ordinarily, upon a verdict for damages and upon motion of a party,
    interest is to be awarded as part of all judgments.” State v. Peter Salvucci Inc.,
    
    111 N.H. 259
    , 262 (1971). Pursuant to RSA 524:1-b, in all civil proceedings,
    other than an action on a debt,
    in which a verdict is rendered or a finding is made for pecuniary
    damages to any party, whether for personal injuries, for wrongful
    death, for consequential damages, for damage to property,
    46
    business or reputation, for any other type of loss for which
    damages are recognized, there shall be added . . . to the amount of
    damages interest thereon from the date of the writ or the filing of
    the petition to the date of judgment.
    RSA 524:1-b; see RSA 524:1-a (2007).
    The interpretation of a statute is a question of law, which we review de
    novo. In the Matter of Liquidation of Home Ins. Co., 
    166 N.H. 84
    , 88 (2014).
    We are the final arbiters of the legislature’s intent as expressed in the words of
    the statute considered as a whole. 
    Id.
     We first examine the language of the
    statute, and, where possible, ascribe the plain and ordinary meanings to the
    words used. 
    Id.
     Our goal is to apply statutes in light of the legislature’s intent
    in enacting them, and in light of the policy sought to be advanced by the entire
    statutory scheme. 
    Id.
    The purpose of the legislature in enacting RSA 524:1-b was “to clarify
    and simplify the existing law and to make plain that in all cases where the trial
    court awarded money to the party entitled to be compensated, interest at the
    legal rate is to be added to the award.” 
    Id. at 89
     (quotation omitted). Even
    assuming, without deciding, that the damages award included some amount
    for “future” costs, the plain language of the statute does not distinguish
    between past and future damages. Rather, the statute mandates the award of
    prejudgment interest “to the amount of damages.” Thus, the plain language of
    the statute provides no support for Exxon’s argument differentiating past and
    future damages for purposes of calculating and awarding prejudgment interest.
    See Starr v. Governor, 
    151 N.H. 608
    , 610 (2004) (we will not add words to a
    statute that the legislature did not see fit to include). Accordingly, we hold that
    the trial court did not err in awarding prejudgment interest as to all of the
    State’s damages.
    XIII. State’s Cross-Appeal
    The State cross-appeals from the trial court’s order imposing a trust
    upon approximately $195 million of the damages award. Before trial, Exxon
    moved “to establish a court supervised trust fund for any monies the State
    recovers in this litigation” and for “an accounting for all settlement proceeds
    the State has received to date.” Exxon argued that the need for a trust fund
    was necessary “given the speculative nature of the State’s future damages,”
    and that a “‘pay-as-you-go’ fund . . . would effectively limit the State’s recovery
    to those future testing, monitoring, treatment, and remediation costs the State
    actually incurs.” The State objected, and the trial court deferred ruling until
    after trial.
    Following the verdict, Exxon renewed its motion, asserting that “[t]he
    need for a court-supervised trust is proven by the recent press coverage
    47
    indicating that the New Hampshire Legislature intends to divert funds awarded
    in this litigation away from MTBE remediation,” and that, in two recent
    Maryland cases, the court had required court-supervised trust funds in
    medical monitoring cases involving alleged MTBE exposures. The State
    objected, arguing, among other contentions, that, because the trial court had
    already determined that “the underlying causes of action do not require the
    State to prove how it will spend damages, there is no basis for imposing a
    court-supervised trust requiring the State to establish how the money will be
    spent as a prerequisite to obtaining the damages for which Exxon was found
    liable.” In addition, the State argued that Exxon “has not cited a single case,
    statute, or other authority that would allow [the trial court] to establish a trust
    fund for monies received by the State pursuant to a jury award in a products
    liability case,” and that Exxon’s reliance upon the Maryland cases was
    misplaced.
    The trial court granted Exxon’s motion in part, agreeing that “a trust is
    necessary to protect the res of the jury damage award.” The trial court
    reasoned that “because the State brought this case in its parens
    patriae/trustee capacity,” the “State’s obligation to remediate contaminated
    water exists independent of Exxon’s interest in the damages figure the jury
    awarded the State,” and the State “must ensure it has adequate resources to
    test and treat New Hampshire’s waters in the future.” The court declined to
    impose a trust upon the amount of damages designated for past cleanup costs,
    reasoning that “those monies must be available upon final judgment” for the
    State to reimburse itself. However, the court imposed a trust upon the amount
    of damages designated for 228 high-risk sites, sampling private drinking water
    wells, and treating drinking water wells contaminated with MTBE at or above
    the maximum contaminant level. The court rejected Exxon’s request for an
    order compelling the State to disclose how it would proceed with testing and
    remediation, but noted that “to the extent Exxon has a legal interest in a trust
    as a beneficiary at the termination of the trust, it may file a proposed
    procedure for how the trust should function.” The trial court deferred deciding
    whether the trust would be court-supervised, and a hearing date was set for
    the court “to consider each party’s proposal for the administrative details of a
    trust.”
    Before the scheduled hearing date, the State moved for reconsideration of
    the trial court’s order, Exxon filed this appeal, and the State filed its cross-
    appeal. We subsequently issued an order staying the appellate proceedings to
    allow the trial court to issue a final decision on the State’s motion for
    reconsideration. The trial court thereafter denied the motion. The court noted
    at the outset that “it would be inefficient for the Court to decide all the relevant
    details of a trust now, if the Supreme Court is being asked to decide whether
    the existence of a trust is permissible. As such, this Court interprets the
    Supreme Court order to require a ruling on imposition of a trust but not the
    details.” The trial court rejected the State’s arguments that, among other
    48
    things, the court conflated parens patriae and the public trust doctrine, failed
    to comply with RSA 6:11, III (Supp. 2014), and violated separation of powers.
    The trial court also rejected the State’s argument that Exxon lacked standing,
    stating that “the Court specifically left open the question of whether Exxon has
    standing” and that “Exxon’s standing was irrelevant to the Court’s
    determination to impose the trust.”
    On appeal, the State argues that the trial court’s imposition of a trust
    was erroneous for several reasons, including that no common law precedent or
    statute provides for the imposition of a trust over the State’s damages award.
    Exxon argues that trial courts have “broad and flexible equitable powers,”
    which include the power to establish a trust over the damages awarded in this
    case. (Quotation omitted.)
    Although we recognize that “[t]he propriety of affording equitable relief in
    a particular case rests in the sound discretion of the trial court,” Libertarian
    Party of N.H. v. Sec’y of State, 
    158 N.H. 194
    , 196 (2008), this principle does not
    apply to the remedy in this case. The common law remedy for a tort law cause
    of action is lump-sum damages. See Reilly v. United States, 
    863 F.2d 149
    , 169
    (1st Cir. 1988) (under the common law rule, “a court’s authority to award
    damages for personal injuries is limited to making lump-sum judgments”); see
    also In re Methyl Tertiary Butyl Ether (“MTBE”), 
    56 F. Supp. 3d 272
    , 273, 275
    (S.D.N.Y. 2014) (declining to impose a reversionary trust on damages awarded
    for Exxon’s liability on claims of public nuisance, negligence, trespass, and
    products liability for failure to warn, because the remedy for a traditional tort
    law cause of action is lump-sum damages). Thus, in the absence of a statute
    or an agreement between the parties, when a tortfeasor loses at trial it must
    pay the judgment in one lump sum. See Reilly, 
    863 F.2d at 170
    ; see also
    Vanhoy v. United States, 
    514 F.3d 447
    , 454-55 (5th Cir. 2008) (court refused
    to deviate from a conventional lump-sum award and create a reversionary trust
    over damages in the absence of any applicable statutory or precedential
    requirement); Frankel v. Heym, 
    466 F.2d 1226
    , 1228-29 (3d Cir. 1972) (“courts
    of law had no power at common law to enter judgments in terms other than a
    simple award of money damages”; thus, “court should not make other than
    lump-sum money judgments” in case brought under Federal Tort Claims Act
    “unless and until Congress shall authorize a different type of award”).
    The trial court reasoned that a trust was required because the State
    brought this action in its parens patriae capacity. Parens patriae, however, is
    simply a standing doctrine. See Hess, 161 N.H. at 431-32. As we explained in
    Hess, “[t]he public trust doctrine, from which the State’s authority as trustee
    stems, and the parens patriae doctrine are both available to states seeking to
    remedy environmental harm.” Id. at 431. “While the public trust doctrine is
    its own cause of action, parens patriae is a concept of standing, which allows
    the state to protect certain quasi-sovereign interests.” Id. at 431-32
    (quotations omitted). “Parens patriae does not provide a cause of action, but
    49
    may provide a state with standing to bring suit to protect a broader range of
    natural resources than the public trust doctrine because it does not require
    state ownership of such resources.” Id. at 432. Accordingly, we are not
    persuaded that the fact that the State was allowed to proceed under parens
    patriae standing authorizes the imposition of a trust over the money damages
    awarded for Exxon’s torts. In the absence of statutory or precedential support,
    we decline to deviate from the conventional lump-sum damages award and,
    accordingly, reverse the trial court’s imposition of a trust as erroneous as a
    matter of law.
    Affirmed in part; and
    reversed in part.
    HICKS, J., and VAUGHAN, J., retired superior court justice, specially
    assigned under RSA 490:3, concurred.
    50