McMunn v. Babcock & Wilcox Power Generation Group, Inc. ( 2017 )


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  •                                   PRECEDENTIAL
    UNITED STATES COURT OF APPEALS
    FOR THE THIRD CIRCUIT
    _____________
    Nos. 15-3506, 15-3507, 15-3508, 15-3509, 15-3510,
    15-3511, 15-3512, 15-3513, 15-3514, 15-3515, 15-3564,
    15-3639, 15-3640, 15-3641, 15-3642, 15-3643, 15-3644,
    15-3645, 15-3646, 15-3647, 15-3648, 15-3649, 15-3650,
    15-3651, 15-3652, 15-3653, 15-3654, 15-3655, 15-3656,
    15-3657, 15-3658, 15-3659, 15-3660, 15-4075, 15-4076,
    15-4077, 15-4078, 16-1694, & 16-1965
    _____________
    MICHELLE MCMUNN, personal representative of the
    Estate of Eva Myers;
    CARA D. STEELE; YVONNE SUE ROBINSON;
    EDWARD J. MYERS;
    LEVI DANIEL STEELE; HAROLD ROBINSON, et al
    v.
    BABCOCK & WILCOX POWER GENERATION
    GROUP, INC.;
    B&W TECHNICAL SERVICES, INC., FKA B&W
    Nuclear Environmental
    Services, Inc.; ATLANTIC RICHFIELD COMPANY,
    predecessors-in-interest,
    successors-in-interest, subdivisions and subsidiaries;
    BABCOCK & WILCOX TECHNICAL SERVICES
    GROUP, INC.
    Apollo Facility Plaintiffs, Appellants
    in Nos. 15-3506, 15-3507, 15-3508,
    15-3509, 15-3510, 15-3511, 15-3512,
    15-3513, 15-3514, 15-3515, 15-3564,
    15-4075, 15-4076, 15-4077, 15-4078,
    16-1964 and 16-1965
    Babcock & Wilcox Power Generation
    Group, Inc. and Babcock & Wilcox
    Technical Services Group, Inc., Appellants
    in Nos. 15-3640, 15-3642, 15-3644,
    15-3646, 15-3648, 15-3650, 15-3652,
    15-3654,15-3656, 15-3658 and 15-3660
    Atlantic Richfield Company, Appellant in
    Nos. 15-3639, 15-3641, 15-3643, 15-3645,
    15-3647, 15-3649, 15-3651, 15-3653,
    15-3655, 15-3657 and 15-3659
    _____________
    On Appeal from the United States District Court
    for the Western District of Pennsylvania
    District Court Nos. 2-10-cv-00143, 2-10-cv-00368,
    2-10-cv-00650, 2-10-cv-00728, 2-10-cv-00744,
    2-10-cv-00908, 2-10-cv-01736, 2-11-cv-00898,
    2
    2-11-cv-01381, 2-12-cv-01221, 2-12-cv-01459,
    2-13-cv-00186, 2-13-cv-00704, 2-13-cv-01527,
    2-14-cv-00639, 2-15-cv-00844, 2-15-cv-01423
    District Judge: The Honorable David S. Cercone
    Argued November 10, 2016
    Before: SMITH, Chief Judge, McKEE, and RESTREPO,
    Circuit Judges
    (Filed: August 23, 2017)
    Louis M. Bograd                [ARGUED]
    Motley Rice
    3333 K Street, N.W.
    Suite 450
    Washington, DC 20007
    Jonathan D. Orent
    Motley Rice
    321 South Main Street
    P.O. Box 6067
    Providence, RI 02904
    Anne McGinness Kearse
    Motley Rice
    28 Bridgeside Boulevard
    Mount Pleasant, SC 29464
    3
    David B. Rodes
    Goldberg Persky & White P.C.
    11 Stanwix Street
    Suite 1800
    Pittsburgh, PA 15222
    Counsel for Appellants
    Stephen B. Kinnaird
    Paul Hastings LLP
    875 15th Street, N.W.
    Suite 1000
    Washington, DC 20005
    Peter C. Meier
    John P. Phillips                [ARGUED]
    Sean D. Unger
    Paul Hastings LLP
    55 Second Street
    24th Floor
    San Francisco, CA 94105
    Nancy G. Milburn                [ARGUED]
    Philip H. Curtis
    Reuben S. Koolyk
    Arnold & Porter LLP
    399 Park Avenue
    34th Floor
    New York, NY 10022
    4
    Geoffrey J. Michael
    Arnold & Porter LLP
    601 Massachusetts Avenue, N.W.
    Washington, DC 20001
    Counsel for Appellees
    _____________________________
    OPINION OF THE COURT
    _____________________________
    SMITH, Chief Judge, joined by RESTREPO, Circuit
    Judge, who also joins in the Concurrence.
    Plaintiffs assert that they developed cancer1 after
    being exposed to excessive radiation emissions from the
    Nuclear Material and Equipment Company (“NUMEC”)
    facility in Apollo, Pennsylvania (the “Apollo facility”).
    Plaintiffs do not challenge the District Court’s
    conclusions that their common-law claims against
    1
    For simplicity’s sake, we refer to the individuals
    diagnosed with cancer as “Plaintiffs” even though several
    of those individuals have died and the executors of those
    individuals’ estates have been substituted as plaintiffs.
    5
    Defendants2 were preempted by the Price-Anderson Act
    and that only their Price-Anderson “public liability”
    claims are at issue in this appeal. Although the Price-
    Anderson Act preempted Plaintiffs’ common-law
    negligence claims, Plaintiffs’ Price-Anderson public
    liability claims require Plaintiffs to prove versions of the
    traditional negligence elements—(1) duty, (2) breach,
    (3) causation, and (4) damages.
    The District Court held that Defendants were
    entitled to summary judgment as a matter of law on the
    Price-Anderson claims because Plaintiffs failed to show
    that there was a genuine dispute of material fact as to
    elements of duty, breach, and damages. Plaintiffs
    appealed. We agree with the District Court: Plaintiffs
    are missing critical elements, and therefore their claims
    fail.
    2
    Defendants are Atlantic Richfield Company and
    Babcock & Wilcox Power Generation Group, Inc.,
    Babcock & Wilcox Technical Services Group Inc., and
    B&W Technical Services Inc.           Atlantic Richfield
    Company and Babcock & Wilcox Power Generation
    Group, Inc., were owners of the NUMEC facility at
    different points in time. See, e.g., JA1467 (stating that
    Atlantic Richfield bought the Apollo facility from
    NUMEC in 1967 and Babcock & Wilcox purchased the
    facility in 1971).
    6
    Accordingly, we will affirm the judgment of the
    District Court.
    BACKGROUND
    I. THE PARTIES AND EMISSIONS
    A. The Parties
    Plaintiffs are more than seventy individuals3 in a
    group of consolidated cases who claim that excessive
    radiation emitted by Defendants—more specifically,
    radiation from uranium effluent from the Apollo
    facility—caused them to develop various cancers.
    Almost all of the Plaintiffs lived near Apollo,
    Pennsylvania, for many years, including the 1960s, and
    almost all of the Plaintiffs were diagnosed with at least
    one form of cancer between 2007 and 2011.4 The
    3
    At oral argument, even Plaintiffs’ counsel was unable to
    fix the exact number of plaintiffs. See Oral Arg. Tr. at
    4:6–19.
    4
    This period of time when most Plaintiffs were
    diagnosed with cancer may reflect that another group of
    individuals who developed cancer had previously sued
    Babcock & Wilcox and Atlantic Richfield Co. Their
    lawsuit apparently settled before trial. See Docket, Hall
    v. Babcock & Wilcox, No. 94-951 (W.D. Pa.); see also
    7
    similarities among the Plaintiffs end there. By our count,
    Plaintiffs alleged that they suffered from more than a
    dozen different types of cancer.5 Plaintiffs were of
    widely varying ages at the times of their diagnoses—with
    at least one individual under 30 and at least five
    individuals over 80. See JA3460 (81); JA3478 (82);
    JA3479 (88); JA3482 (81); JA3485 (29); JA3491 (82).
    Many of the Plaintiffs had extensive smoking histories,
    and some had multiple cancer diagnoses over their
    lifetimes. See, e.g., JA3474 (“smoked about half a pack
    per day for 40 years”); JA3463 (“diagnosed with breast
    cancer in 1986 and then again in 2008 at the age of 67”).
    Hall v. Babcock & Wilcox, No. 94-951, 
    2007 WL 1740852
     (W.D. Pa. June 14, 2007). The diagnosis date
    range here may also reflect statute of limitations
    concerns. The statute of limitations is not an issue in this
    appeal.
    5
    See, e.g., JA3447 (“Non Hodgkin’s Lymphoma”);
    JA3448 (“lung cancer”); JA3449 (“breast cancer”);
    JA3450 (“esophageal cancer”); JA3451 (“colorectal
    cancer”); JA3455 (“thyroid cancer”); JA3457 (“kidney
    cancer”); JA3458 (“endometrial cancer”); JA3459
    (“bladder cancer”); JA3465 (“melanoma”); JA3474
    (“prostate cancer”); JA3479 (“metastatic ovarian
    cancer”); JA3485 (“squamous cell tumor of her pelvis”).
    8
    B. The Facility
    The Apollo facility was a “warehouse style
    building that was not specifically constructed to house
    the complex manufacturing operation involving
    radioactive materials.”       JA1427.      As Plaintiffs
    emphasize, the Apollo facility was adjacent to a steel mill
    and “in the immediate neighborhood of residential
    areas.” JA1576.
    The Apollo facility operated from approximately
    1953 to 1983 with uranium fuel manufacture beginning
    in 1958 and decommissioning beginning in 1978. See
    JA1467; McMunn v. Babcock & Wilcox Power
    Generation Grp., 
    131 F. Supp. 3d 352
    , 356 (W.D. Pa.
    2015).
    The Atomic Energy Commission (“AEC”) was the
    federal regulatory body in charge of overseeing the
    Apollo facility. During the time that the Apollo facility
    operated, the Nuclear Regulatory Commission (“NRC”)
    became “the statutory successor to the Atomic Energy
    Commission.” In re TMI, 
    67 F.3d 1103
    , 1112 (3d Cir.
    1995).
    The Apollo facility emitted radiation as a
    necessary byproduct of manufacturing uranium fuel.
    Plaintiffs argue that that radiation was in excess of
    regulatory limits. The focus in this dispute is on
    radiation emitted from the stacks, vents, and fans on the
    Apollo facility’s roof.
    9
    C. Evidence of Excessive Emissions
    Much of Plaintiffs’ evidence of excessive
    emissions indicates that emissions from the stacks or
    vents on the roof exceeded the maximum permissible
    concentration (“MPC”) for the facility. Plaintiffs do not
    contest that the relevant maximum permissible
    concentration is 8.8 disintegrations per minute per cubic
    meter (dpm/m3). See McMunn, 131 F. Supp. 3d at 373
    n.24; Pls.’ Br. 10; cf. JA3642.
    As discussed below, under the applicable
    regulations, the maximum permissible concentration is
    determined at the boundary of the “unrestricted area.”
    Defendants argue that the boundary of the unrestricted
    area is the boundary of the roof, while Plaintiffs argue
    that any emissions from any part of the roof—including
    emission from any stack, vent, or fan—should be less
    than the maximum permissible concentration.
    Plaintiffs point to evidence that they believe
    supports their position. In a June 5, 1964 letter, the
    Director of the Division of State and Licensee Relations
    of the AEC implied that the NUMEC had not shown that
    the roof was a restricted area: “[T]he roof area of the
    NUMEC facility is an unrestricted area unless access to
    this area is controlled from the radiation safety
    standpoint.” JA5314. Consistent with the 1964 letter
    implying that the entire roof may be unrestricted,
    Plaintiffs argue that NUMEC and AEC’s course of
    conduct shows that they both thought that stack
    10
    emissions were a regulatory concern because NUMEC
    and AEC compared stack emissions to the maximum
    permissible concentration. For instance, in a 1967 report,
    a NUMEC employee wrote, “[T]he measured stack
    concentration frequently exceeds permissible levels.”
    JA5201. The AEC similarly expressed concern about
    releases from stacks, as though the regulations created
    limitations on the stacks. In a February 5, 1969 letter, the
    Director of the Division of Compliance of the AEC
    warned, “Based on your recorded data, the concentrations
    of radioactive material released from the facility through
    exhaust stacks to unrestricted areas exceed the limits
    specified in Appendix B, Table II of 10 CFR 20, contrary
    to 10 CFR 20.105(a), ‘Concentrations in effluents to
    unrestricted areas.’” JA4700.
    In addition to the evidence about emissions from
    the stacks or vents, Plaintiffs’ evidence of excessive
    emissions fits into one or more of the following three
    categories: (1) evidence that the monitoring of emissions
    was not completely comprehensive; (2) data that there
    was excessive radiation in the area surrounding the
    facility; and (3) data showing excessive radiation being
    released but seemingly only for specific, and short,
    11
    periods of time (such as when the facility’s incinerator
    was being used).6
    Plaintiffs marshaled a large number of documents
    that they alleged created a genuine issue of material fact.
    The highlights of Plaintiffs’ documents are below:
     In an April 20, 1964 letter, NUMEC
    Manager E.V. Barry wrote to Eber R. Price
    at the AEC that “average yearly
    concentrations at our property line” were
    being exceeded “when the winds are from
    the south quadrant” or in sections “when the
    winds are from the east quadrant.” JA5163.
    6
    Our summary of Plaintiffs’ evidence mirrors Plaintiffs’
    own summary presented at the conclusion of oral
    argument. When asked about “discharges measured at
    the roof edge,” Plaintiffs’ counsel (1) asserted that
    Defendants’ “roof edge monitoring . . . is remarkably
    incomplete”; (2) pointed to an April 20, 1964 letter
    (discussed below) in which NUMEC admitted that it
    sometimes exceeded permissible concentrations at the
    boundary of the roof; (3) highlighted the airborne
    concentrations of effluent when the plant’s incinerator
    was operating; and (4) noted “environmental monitors in
    the community.” Oral Arg. Tr. at 39:10–40:20.
    12
     Data for part of the year 1966 shows a high
    of 41.5 dpm/m3 and an average of 13.0
    dpm/m3. See JA5188. But, as Plaintiffs
    admit, the “high” refers to only one day.
    See Pls.’ Br. 47–48 (referring to “the same
    day” that the sampler gave its “highest
    reading”). Additionally, this data comes
    from a nearby building and not the roof of
    the Apollo facility. Compare JA5188, with
    JA5189.
     An August 18, 1967 internal memorandum
    about the Apollo facility’s incinerator states,
    “Ever since the incinerator has been in
    operation it has been a consistent source of
    airborne contamination causing an over
    exposure [sic] to the operators and air levels
    above the M.P.C. in and out of the plant.”
    JA4428.
     In a February 5, 1969 letter, the Director of
    the Division of Compliance of the AEC
    wrote, among other things, “Based on your
    recorded data, the concentrations of
    radioactive material released from the
    facility through exhaust stacks to
    unrestricted areas exceed the limits specified
    in Appendix B, Table II of 10 CFR 20,
    contrary     to     10    CFR      20.105(a),
    13
    ‘Concentrations in effluents to unrestricted
    areas.’” JA4700.
     A     November        30,   1972     internal
    memorandum memorializing a phone call
    from the AEC states that the AEC
    commented that “NUMEC has been the
    worst offender of AEC regulations over the
    years,” that “[t]he AEC is strongly
    considering imposing civil penalties,” and
    mentions NUMEC was implementing
    corrective actions in, among other things, its
    “Liquid Waste Management Program,” and
    “Building Ventilation and Surveillance
    Program.” See JA4439–40.
     In a February 12, 1974 letter, a NUMEC
    employee criticized the Apollo facility for
    releasing too much radiation. See JA4422
    (“It is . . . apparent from review of the data
    that said operations at the Apollo Site are
    not conducted so as to provide a minimal
    radiological         impact       on       the
    environment . . . .”). The same letter further
    states that there was heightened radioactivity
    in the area near the Apollo facility, many
    times in multiple of the background
    radiation because of “radiologically
    contaminated gaseous effluents.” Id.
    14
     A July 9, 1974 internal memorandum
    complains about “stack and liquid discards
    of SNM [special nuclear material] from the
    Apollo Plant” and tremendous losses of
    uranium through “gross irresponsibility.”
    See JA4427.
    However, AEC/NRC approved NUMEC’s
    operations at least three times. First, in a report
    timestamped July 29, 1966, the AEC wrote, “No item of
    noncompliance       with     respect   to    [NUMEC’s]
    concentrations of radioactive effluents released to
    unrestricted areas was noted as a result of this
    investigation.” JA5051. Second, in 1968, the AEC
    concluded that NUMEC’s roof edge samples were below
    the maximum permissible concentrations. JA5057 (“As
    can be seen, these average sample results are below 8.8
    [dpm/m3].”). On May 26, 1969, the AEC granted an
    amendment to NUMEC’s license, “authoriz[ing] the
    discharge of radioactive material from any stack
    effluent . . . in concentrations up to one-hundred . . .
    times the applicable limits . . . in accordance with the
    statements, representations and conditions specified in
    your application dated March 5, 1969.” JA5112.
    Finally, in 1995, the NRC issued a report
    investigating another NUMEC facility in Parks,
    Pennsylvania. See 
    60 Fed. Reg. 35,571
    , 35,573 (1995).
    In that report, the NRC stated that, despite the 1969
    license amendment setting limits for stack emissions, the
    15
    regulatory limits were set at the boundary of the roof:
    “Accordingly, even though NUMEC was authorized to
    discharge at the stack up to 100 times the value specified
    in Appendix B, Table II, [under the 1969 license
    amendment,] NUMEC was still required to meet the
    limits at the site boundary (see footnote 8).” 
    60 Fed. Reg. 35,571
    , 35,573 (1995). Footnote 8, in turn, states,
    “The values set forth in 10 CFR Part 20, Appendix B,
    Table II, are the regulatory limits applicable at the site
    boundary, not at the stack.” 
    60 Fed. Reg. 35,571
    , 35,573
    n.8 (1995).
    II. THE SCIENCE OF CANCER
    This Court’s previous opinion, In re TMI
    Litigation, 
    193 F.3d 613
     (3d Cir. 1999), set forth the
    basic scientific principles regarding the relationship
    between radiation and cancer. See 
    193 F.3d at
    629–55.
    No party disputes those background principles. Because
    we rely on these principles here, we consider it helpful to
    summarize them. Ionizing radiation can damage human
    cells. 
    Id.
     at 639–40. “If cellular damage is not repaired,
    [the damage] may prevent the cell from surviving or
    reproducing, or it may result in a viable but modified
    cell.” 
    Id. at 640
    . When an irradiated cell is only
    “modified rather than killed,” stochastic (or probabilistic)
    effects result. 
    Id. at 642
    .
    As the word “probabilistic” indicates, what
    happens next to the modified cell is uncertain. In some
    cases, “cancer induction” occurs. 
    Id.
     As we explained in
    16
    In re TMI Litigation, any increase in radiation exposure
    above zero is believed to increase the probability of
    carcinogenesis7:
    The probability that cancer will result from
    radiation increases proportionally with dose.
    However, it is currently believed that there
    is no threshold dose below which the
    probability of cancer induction is zero. . . .
    The linear risk model posits that each time
    energy is deposited in a cell or tissue, there
    is a probability of the induction of cancer.
    
    Id.
     at 642–43 (citations omitted).
    Even with state-of-the-art data, it is impossible to
    determine with certainty that radiation is the cause of a
    given incidence of cancer for three reasons. First,
    numerous factors other than radiation may cause cancer.
    That is, “a given percentage of a defined population will
    contract cancer even absent any exposure to ionizing
    radiation.” 
    Id.
     a 643–44.8 Second, there is no clear
    7
    “Carcinogenesis is currently believed to be a multistep
    process requiring two or more intracellular events to
    transform a normal cell into a cancer cell.” In re TMI
    Litig., 
    193 F.3d 613
    , 643 (3d Cir. 1999).
    8
    “[T]he task of establishing causation is greatly
    complicated by the reality that a given percentage of a
    17
    difference between cancers caused by radiation or by
    other factors. No characteristic of a given cancer (such
    as its type or severity) are known to suggest that
    “manmade” radiation or even any radiation was the
    cancer’s cause. See 
    id. at 643
     (“[M]edical evaluation, by
    itself, can neither prove nor disprove that a specific
    malignancy was caused by a specific radiation
    exposure.”). Third, because the relevant changes occur
    on the cellular level, they are not detected or detectable at
    the time they occur. It can take many years—seemingly
    a variable number of years—between an exposure to
    radiation and the “possible detection of a resulting
    cancer.” 
    Id.
     (defining the “latency period” as “[t]he
    period between exposure to radiation and possible
    detection”). Thus, in a case like this one, the factfinder
    will always have to use ex-post data to ascertain whether
    any radiation—let alone any particular radioactive
    exposure—disrupted the cell in the past.
    defined population will contract cancer even absent any
    exposure to ionizing radiation.       In industrialized
    countries where the life expectancy averages about 70
    years, about 30% of the population will develop cancer
    and about 20% of the population will die of cancer.” In
    re TMI Litig., 
    193 F.3d at
    643–44.
    18
    III. THE DISTRICT COURT’S RELEVANT
    RULINGS
    We are reviewing the orders granting Defendants’
    motion for summary judgment. In its summary judgment
    orders, the District Court adopted the reasoning of the
    Magistrate Judge to whom all pretrial motions had been
    referred. See Order, McMunn v. Babcock & Wilcox
    Power Generation Grp., No. 2:10-cv-00143-DSC-RCM
    (W.D. Pa. Aug. 24, 2011), ECF No. 79.
    Two earlier rulings set the stage for the summary
    judgment motion. Those two rulings are (1) a September
    12, 2012 order following a “Lone Pine” case
    management order,9 and (2) a February 27, 2014 order
    adopting in part and rejecting in part the Magistrate
    Judge’s recommendations with regard to excluding the
    parties’ experts under Daubert v. Merrell Dow
    Pharmaceuticals, Inc., 
    509 U.S. 579
     (1993).
    9
    A Lone Pine order is a pretrial order, based on Lore v.
    Lone Pine Corp., No. L-33606-85, 
    1986 WL 637507
    (N.J. Super. Ct. Law Div. Nov. 18, 1986), that “require[s]
    plaintiffs to provide facts in support of their claims”
    including by expert evidence “or risk having their cases
    dismissed.” In re Asbestos Prods. Liab. Litig. (No. VI),
    
    718 F.3d 236
    , 240 & n.2 (3d Cir. 2013).
    19
    A. Lone Pine
    On January 25, 2012, the Magistrate Judge issued
    the Lone Pine order, requiring Plaintiffs to provide prima
    facie evidence of, among other things, the “name of the
    specific radionuclide(s) released from Defendants’
    facilities in excess of the applicable federal permissible
    limits” and “an identification of each exposure
    pathway(s) through which each Plaintiff was exposed to
    each specific radionuclide.” Order at 1, McMunn v.
    Babcock & Wilcox Power Generation Grp., No. 2:10-cv-
    0143-DSC-RCM (W.D. Pa. Jan. 25, 2012), ECF No. 109.
    On September 12, 2012, following the parties’
    responses to the Lone Pine order, the Magistrate Judge
    issued an order limiting Plaintiffs’ theories of recovery.
    See McMunn v. Babcock & Wilcox Power Generation
    Grp., 
    896 F. Supp. 2d 347
     (W.D. Pa. 2012). In that
    order, the Magistrate Judge held that the Plaintiffs would
    be allowed only “to pursue, offer or rely upon evidence
    referring or relating to any claim based upon exposure
    through . . . airborne exposure to uranium . . . from . . .
    the Apollo facility during its years of operation.” 
    Id.
     at
    358–61; see also id. at 364. Plaintiffs do not challenge
    this Lone Pine order on appeal.
    B. Daubert
    On July 12, 2013, the Magistrate Judge
    recommended that the District Court (1) grant some of
    Defendants’ Daubert motions; (2) deny the remainder of
    20
    Defendants’ Daubert motions; and (3) deny all of
    Plaintiffs’ Daubert motions. See McMunn v. Babcock &
    Wilcox Power Generation Grp., Nos. 10-143 et al., 
    2013 WL 3487560
     (W.D. Pa. July 12, 2013). Specifically, the
    Magistrate Judge recommended excluding the testimony
    of Plaintiffs’ three general causation experts—Dr.
    Howard Hu, Dr. Joseph Ring, and Mr. Bernd Franke—
    and Plaintiffs’ specific causation expert, Dr. James
    Melius. Only the rulings with regard to Melius’s
    testimony bear directly on this appeal.
    Melius’s expert report used the methodology of
    differential diagnosis. Melius provided a roughly one-
    page summary of each Plaintiff’s background and alleged
    exposure and then concluded for each Plaintiff: “[I]t is
    my professional medical opinion that [Plaintiff’s]
    exposures to uranium and other radioactive materials
    released from the Apollo nuclear facility made a
    significant contribution to the development of” his or her
    cancer. E.g., JA3448, 3465, 3490. For most of the
    Plaintiffs, Melius added language substantially like the
    following: “This is reinforced by the lack of other risk
    factors in [her or his] history that would account for the
    development of this illness.” E.g., JA3448.10
    10
    For a handful of Plaintiffs—but only some of the
    Plaintiffs with a history of smoking—Melius identified
    smoking as the only confounding factor. E.g., JA3451
    21
    The Magistrate Judge recommended excluding
    Melius’s testimony because Melius failed to rule out
    other confounding factors and did not have information
    about doses of radiation to which each Plaintiff was
    exposed. With regard to confounding factors, the
    Magistrate Judge criticized Melius’s “differential
    diagnosis” because Melius “fail[ed] to explain why he
    did not rule out smoking, obesity, genetic factors,
    benzene exposure, radon and many other possible and
    obvious alternative causes in order to conclude in each
    instance that uranium is the cause of the individual’s
    cancer.” McMunn, 
    2013 WL 3487560
    , at *28. With
    regard to dose, the Magistrate Judge criticized Melius for
    failing to make or use any estimate of any Plaintiff’s dose
    “or the maximum or minimum amount to which the
    person was exposed.” Id. at *29. Instead, to determine
    that Plaintiffs’ exposures were sufficient to serve as a
    “significant contribution” to their cancers, Melius relied
    on general testimony about radiation—Dr. Hu’s
    testimony that radiation from uranium could cause
    cancer—and the assumption that Plaintiffs were exposed
    to dangerous levels of radiation because “the Plaintiffs
    lived or worked within 1.5 miles of the Apollo facility.”
    (“This is reinforced by the lack of other risk factors in his
    history that would account for the development of this
    illness other than smoking which also would have made a
    contribution.”).
    22
    Id. at *28. The Magistrate Judge’s two criticisms
    dovetailed with a particular flaw in Melius’s testimony:
    Melius “rule[d] out oral contraceptive use if the dose was
    small and smoking if the person quit 10–15 years ago,
    thereby taking dose into account.” Id. at *29. The
    Magistrate Judge concluded that Melius’s methodology
    “has not been generally accepted in the medical and
    scientific communities” and was “untestable.” Id. at *29.
    On February 27, 2014, the District Court rejected
    the Magistrate Judge’s report and recommendation to the
    extent that the Magistrate Judge recommended granting
    Defendants’ Daubert motions with regard to Melius and
    Plaintiffs’ general causation experts.11 With regard to
    Melius specifically, the District Court placed great
    weight on (1) this Court’s past discussion of differential
    diagnosis methodology and (2) the fact that Melius did
    not have access to perfect information. First, the District
    Court held that Melius “adequately addressed other
    possible causes of Plaintiffs’ cancers, both known and
    11
    The District Court adopted the portion of the report and
    recommendation in which the Magistrate Judge
    recommended denying the exclusion of Defendants’
    experts and denying the exclusion of most of Plaintiffs’
    experts. See McMunn v. Babcock & Wilcox Power
    Generation Grp., Nos. 2:10cv143 et al., 
    2014 WL 814878
    , at *20 (W.D. Pa. Feb. 27, 2014).
    23
    unknown” because Melius reviewed information about
    the Plaintiffs. McMunn v. Babcock & Wilcox Power
    Generation Grp., Nos. 2:10cv143 et al., 
    2014 WL 814878
    , at *14 (W.D. Pa. Feb. 27, 2014). The District
    Court also cited and quoted In re Paoli Railroad Yard
    PCB Litigation, 
    35 F.3d 717
     (3d Cir. 1994), and Heller v.
    Shaw Industries, Inc., 
    167 F.3d 146
     (3d Cir. 1999), for
    the propositions that a medical expert performing a
    differential diagnosis does not need to rule out every
    alternative factor and that medical experts are permitted
    to exercise their judgments when conducting a
    differential diagnosis. See McMunn, 
    2014 WL 814878
    ,
    at *15.
    Second, with regard to dose, the District Court
    held that there was “enough support in the record for the
    contention that the Plaintiffs’ exposure levels exceeded
    the normal background level” for Melius to use a
    “qualitative analysis” rather than a “quantitative dose
    analysis.” Id. at *14. In particular, Melius could rely on
    “NUMEC’s failure to monitor emissions.” Id. Because
    Melius’s analysis relied on the absence of data, the
    District Court agreed with Melius that a “quantitative
    dose calculation . . . may in fact be far more speculative
    than a qualitative analysis.” Id.
    The District Court further held that a dose analysis
    was not necessary for Plaintiffs’ claims to succeed. The
    District Court stated that In re TMI Litigation, 
    193 F.3d 613
     (3d Cir. 1999), “did not require a plaintiff prove a
    24
    quantified dose in order to prove personal injuries caused
    by the release of radiation.” McMunn, 
    2014 WL 814878
    ,
    at *13. Then, the District Court cited to other cases that
    did not require a dose. 
    Id.
     at *13–14 (quoting and citing
    Kannankeril v. Terminix Int’l, 
    128 F.3d 802
    , 808–09 (3d
    Cir. 1997), Bonner v. ISP Techs., Inc., 
    259 F.3d 924
     (8th
    Cir. 2001), and Westberry v. Gislaved Gummi AB, 
    178 F.3d 257
     (4th Cir. 1999)).
    At Defendants’ request, the District Court certified
    the Daubert order for interlocutory appeal. See McMunn
    v. Babcock & Wilcox Power Generation Grp., Nos.
    2:10cv143 et al., 
    2014 WL 12530940
     (W.D. Pa. May 7,
    2014). We denied Defendants’ petition for interlocutory
    appeal. See McMunn v. Babcock & Wilcox Power
    Generation Grp., No. 14-8074 (3d Cir. June 16, 2014).
    C. Summary Judgment
    On May 7, 2015, the Magistrate Judge filed a very
    thorough report recommending that the District Court
    grant Defendants’ motion for summary judgment on
    Plaintiffs’ Price-Anderson public liability claims and
    Defendants’ motion for a judgment on the pleadings on
    all of Plaintiffs’ common-law claims. See McMunn v.
    Babcock & Wilcox Power Generation Grp., 
    131 F. Supp. 25
    3d 352, 359–404 (W.D. Pa. Sept. 15, 2015) (republishing
    the report and recommendation).12
    The Magistrate Judge recommended that the
    District Court grant summary judgment because
    Plaintiffs (1) failed “to raise a genuine issue for trial on
    breach of duty” and (2) failed “to proffer evidence of
    exposure and dose.” Id. at 389, 404.13 First, with regard
    to the breach of duty, the Magistrate Judge held that
    “[t]he regulatory standard applicable to the emission of
    radionuclides in airborne effluent to off-site areas . . .
    when the Apollo facility operated . . . was 
    10 C.F.R. § 20.106
    ”—“not some other regulation, license
    requirement or other issue.” 
    Id.
     at 368–69, 388; see also
    In re TMI, 
    67 F.3d 1103
    , 1108 n.10 (3d Cir. 1995)
    12
    Because Plaintiffs did not appeal the District Court’s
    adoption of the Magistrate Judge’s recommendation to
    dismiss Plaintiffs’ common-law claims, we need not
    discuss the common-law claims.
    13
    The Magistrate Judge did not reach any other issues
    regarding Plaintiffs’ Price-Anderson public liability
    claims. As the Magistrate Judge noted, Defendants
    raised other issues in separate summary judgment
    motions that the District Court denied as moot or denied
    without prejudice to refile. See McMunn, 131 F. Supp.
    3d at 361 & n.3, 404.
    26
    (applying “the relevant federal regulations . . . in place at
    the time” of the radioactive release caused by Three Mile
    Island accident at issue).
    Section 20.106 prohibited a licensee from
    “releas[ing] to an unrestricted area radioactive material in
    concentrations which exceed the limits specified in
    Appendix ‘B’, Table II of this part.” 
    10 C.F.R. § 20.106
    (a) (1980). The regulation further states that
    “the concentration limits in Appendix ‘B’, Table II of
    this part shall apply at the boundary of the restricted
    area.” 
    10 C.F.R. § 20.106
    (d).
    The Magistrate Judge rejected Plaintiffs’ argument
    that the Table II maximum permissible concentration
    applied directly to the uranium effluent released from the
    stacks on the roof.         First, the Magistrate Judge
    determined that the roof of the Apollo facility was a
    restricted area. McMunn, 131 F. Supp. 3d at 386–87.
    Second, the Magistrate Judge held that the measurements
    of uranium effluent to be compared to the maximum
    permissible concentration should be those taken “at the
    roof boundary.” Id. at 387–88. Because Plaintiffs’ only
    expert testimony about breach applied the concentration
    limits at the stacks and not at the roof boundaries, the
    Magistrate Judge held that Plaintiffs failed to proffer
    expert evidence of a breach that raised a genuine issue of
    material fact. See id. at 389.
    With regard to exposure and dose, the Magistrate
    Judge held that Plaintiffs’ causation case failed because
    27
    Plaintiffs failed to show that each Plaintiff was exposed
    to enough radiation to cause his or her cancer. First, the
    Magistrate Judge granted Defendants’ motion to deem
    certain facts admitted. See id. at 394; Plaintiffs’ Local
    Rule 56.C.1 Response, No. 2:10-cv-001343-DSC-RCM
    (W.D. Pa. filed Dec. 5, 2014), ECF No. 342. Then, the
    Magistrate Judge explained that, under In re TMI
    Litigation, 
    193 F.3d 613
     (3d Cir. 1999), each Plaintiff
    had to show that he or she was exposed to “inhaled
    uranium from the Apollo plant in excess of normal
    background radiation amounts.” McMunn, 131 F. Supp.
    3d at 396–97, 399. Thus, the Magistrate Judge held that
    “Plaintiffs must provide . . . an estimate of the dose they
    received which caused their cancers.” Id. at 399. As
    discussed above, Melius relied on Plaintiffs’ other
    experts for exposure, but none of Plaintiffs’ other experts
    calculated exposure or dose for any of the Plaintiffs. See
    id.
    Further, the Magistrate Judge rejected Plaintiffs’
    argument that Defendants were “estopped from
    contesting [Plaintiffs’] lack of evidence of exposure and
    dose” because Defendants failed to keep accurate
    records. Id. at 402–04. The Magistrate Judge also
    rejected Plaintiffs’ argument that law of the case required
    the Magistrate Judge to deny summary judgment on
    causation because the District Court had ruled that
    Melius’s testimony was admissible in its Daubert ruling.
    See id. at 399–402.
    28
    On September 15, 2015, the District Court adopted
    the Magistrate Judge’s report and recommendation over
    Plaintiffs’ objections. See id. at 357. The District Court
    stated that it “review[ed] . . . the record of these
    cases, . . . the Magistrate Judge’s Report and
    Recommendation, and the Objections thereto,” but
    offered no further explanation for its decision. Id.
    Certain related cases were not consolidated with
    the main case when the District Court issued its
    September 15, 2015 Memorandum Order. The District
    Court ultimately entered orders adopting the reasoning of
    the September 15, 2015 Memorandum Order in those
    cases. See JA281–92; SJa3–SJa8.
    Timely notices of appeal followed in each case
    before us.14 Additionally, Defendants cross-appealed
    many—but not all—of the cases before us, requesting
    that we reverse the District Court’s Daubert order.
    14
    Plaintiffs’ Notices of Appeal also objected to orders
    excluding the expert report of Dr. Steve Wing. See, e.g.,
    Ja1. Because Plaintiffs presented no argument regarding
    Dr. Wing’s report, any issues or objections concerning it
    have been waived.
    29
    JURISDICTION
    The District Court had subject-matter jurisdiction
    over these actions under 
    42 U.S.C. § 2210
    (n)(2) because
    this is a public liability action arising out of a nuclear
    incident in the Western District of Pennsylvania. This
    Court has jurisdiction over Plaintiffs’ appeals under 
    28 U.S.C. § 1291
    .
    Plaintiffs argue that we did not have jurisdiction
    over Defendants’ cross-appeal relating to the District
    Court’s denial of their Daubert motion regarding Melius
    because Defendants are not aggrieved by that denial. As
    the Supreme Court observed in Deposit Guaranty
    National Bank v. Roper, “Ordinarily, only a party
    aggrieved by a judgment or order of a district court may
    exercise the statutory right to appeal therefrom. A party
    who receives all that he has sought generally is not
    aggrieved by the judgment affording the relief and cannot
    appeal from it.” 
    445 U.S. 326
    , 333 (1980); see also
    Nanavati v. Burdette Tomlin Mem’l Hosp., 
    857 F.2d 96
    ,
    102 (3d Cir. 1988) (“Because they are completely
    satisfied with the final judgment and object only to
    interlocutory rulings of the district court, we lack
    jurisdiction over their appeal.”).
    We need not determine whether we have
    jurisdiction. We simply follow Third Circuit practice and
    dismiss Defendants’ cross-appeals as “superfluous.”
    Smith v. Johnson & Johnson, 
    593 F.3d 280
    , 283 n.2 (3d
    Cir. 2010) (“Yet a party, without taking a cross-appeal,
    30
    may urge in support of an order from which an appeal
    has been taken any matter appearing in the record, at
    least if the party relied on it in the district court.”). As
    such, we consider the parties’ Daubert arguments to
    concern causation only as an “alternate ground for
    affirmance.” Nanavati, 
    857 F.2d at 102
    . Accordingly,
    we have disregarded Defendants’ reply brief in support
    of their cross-appeal.
    STANDARD OF REVIEW
    The standard of review on summary judgment is
    well known: “Because we are reviewing a grant of
    summary judgment, our standard of review is plenary.
    Summary judgment is appropriate ‘if the movant shows
    that there is no genuine dispute as to any material fact
    and the movant is entitled to judgment as a matter of
    law.’” Constitution Party of Pa. v. Cortes, 
    824 F.3d 386
    ,
    393 (3d Cir. 2016) (citations omitted) (quoting Fed. R.
    Civ. P. 56(a)).
    DISCUSSION
    We will affirm the judgment of the District Court
    because Plaintiffs failed to raise an issue of fact that
    would allow a reasonable jury to find that Defendants
    breached their duty and because Melius’s conclusory
    expert report would not allow a reasonable jury to find
    that Defendants’ radiation was a substantial factor in
    causing Plaintiffs’ cancers.
    31
    I. DUTY
    The District Court15 held that Plaintiff failed to
    establish a genuine issue of material fact as to whether
    Defendants breached their duty to Plaintiffs. We agree
    with the District Court that Defendants’ duty was defined
    by § 20.106.
    In three different ways, Plaintiffs try to show that
    Defendants owed a duty other than to prevent the release
    of uranium effluent that exceeds the maximum
    permissible concentrations at the boundary of the roof,
    when the effluent is averaged over a full year. First,
    Plaintiffs argue that any emission from the roof counts
    under § 20.106. Second, Plaintiffs argue that more
    onerous maximum permissible concentrations for roof
    emissions were created by the 1969 amendment to
    NUMEC’s license. And, third, Plaintiffs argue that they
    had the option to decline annual averaging, allowing
    them to find breaches of duty where emissions exceeded
    15
    Because the District Court “adopt[ed] the Report and
    Recommendation as the Opinion of [the District] Court,”
    McMunn v. Babcock & Wilcox Power Generation Grp.,
    
    131 F. Supp. 3d 352
    , 357 (W.D. Pa. 2015), “we will refer
    to the adopted opinion as that of the district court,” USX
    Corp. v. Liberty Mut. Ins. Co., 
    444 F.3d 192
    , 197 n.8 (3d
    Cir. 2006).
    32
    the maximum permissible concentration over short
    periods of time. As discussed below, these attempts to
    redefine the duty fail because they all conflict with
    § 20.106 and because we owe Auer deference to the
    NRC’s interpretation of § 20.106.
    A. The Roof Was a Restricted Area
    Under § 20.106(d), the maximum permissible
    concentrations are assessed “at the boundary of the
    restricted area.” 
    10 C.F.R. § 20.106
    (d). A “restricted
    area” is any area where “access . . . is controlled by the
    licensee for purposes of protection of individuals from
    exposure to radiation and radioactive materials.” 
    10 C.F.R. § 20.3
    (a)(14). Plaintiffs argue that the entire roof
    was unrestricted16 such that emissions from anywhere on
    the roof—including the stacks and fans—should count
    directly against the limits. Plaintiffs’ argument is
    undermined by a 1995 NRC report that states that the
    “regulatory limits [are] applicable at the site boundary,
    16
    The definition of “unrestricted area” is merely a mirror
    of the definition of “restricted area”: “‘Unrestricted area’
    means any area access to which is not controlled by the
    licensee for purposes of protection of individuals from
    exposure to radiation and radioactive materials, and any
    area used for residential quarters.”            
    10 C.F.R. § 20.3
    (a)(17).
    33
    not at the stack.”   
    60 Fed. Reg. 35,571
    , 35,573 n.8
    (1995).
    Plaintiffs present two arguments as to why the roof
    is unrestricted: (1) an historical argument based on a
    series of letters between the AEC and NUMEC and (2) a
    functional argument that questions whether access to the
    roof was “controlled by the licensee for purposes of
    protection of individuals from exposure to radiation and
    radioactive materials.”
    With regard to the historical argument, Plaintiffs’
    strongest support is a June 5, 1964 letter, in which the
    Director of the Division of State and Licensee Relations
    of the AEC stated that the roof would be “unrestricted” if
    access were not controlled: “[T]he roof area of the
    NUMEC facility is an unrestricted area unless access to
    this area is controlled from the radiation safety
    standpoint.” JA5314.
    Plaintiffs also rely on other correspondence in
    which NUMEC and AEC compared stack emissions to
    the applicable maximum permissible concentration. For
    instance, in a 1967 report, a NUMEC employee wrote,
    “[T]he measured stack concentration frequently exceeds
    permissible levels.” JA5201. The AEC similarly
    expressed concern about releases from stacks, as though
    the regulations created limitations on the stacks. In a
    February 5, 1969 letter, the Director of the Division of
    Compliance of the AEC warned, “Based on your
    recorded data, the concentrations of radioactive material
    34
    released from the facility through exhaust stacks to
    unrestricted areas exceed the limits specified in Appendix
    B, Table II of 10 CFR 20, contrary to 10 CFR 20.105(a),
    ‘Concentrations in effluents to unrestricted areas.’”
    JA4700. Additionally, the fact that NUMEC sought—
    and the AEC granted in 1969—approval to exceed the
    maximum permissible concentration by one-hundred
    times at the stack, see JA5112, suggests that there was a
    pre-existing regulatory limit at the stack.
    Plaintiffs’ functional argument focuses on the
    definition of a restricted area in the regulation. The
    regulation states that a “restricted area” is any area where
    “access . . . is controlled by the licensee for purposes of
    protection of individuals from exposure to radiation and
    radioactive materials.” 
    10 C.F.R. § 20.3
    (a)(14). It is
    uncontested that the roof could only be accessed by
    locked hatches from ladders located inside the building.
    See JA5035–36 (“There are no outside ladders on
    NUMEC’s property. We have two inside ladders with
    normally closed and locked hatches at the top.”); JA5317
    (“The roof hatch is kept locked with keys in the
    possession of the health and safety technician.”).17
    17
    Plaintiffs argue that NUMEC conceded that the roof is
    unrestricted based on the 1966 letter from NUMEC to the
    AEC that states, “We regard the roof area as an
    unrestricted area.”      JA4649.     The District Court
    35
    Plaintiffs argue that these hatches do not show that
    the roof was “controlled . . . for purposes of
    protection . . . from exposure to radiation.” Relying on a
    1965 NUMEC letter, they argue that certain safety
    measures—e.g., alpha survey instruments—are required
    to show why the access is controlled. See Pls.’ Br. 40–
    41.
    concluded that “unrestricted” was “a typographical
    error.” McMunn v. Babcock & Wilcox Generation Grp.,
    
    131 F. Supp. 3d 352
    , 378 (W.D. Pa. 2015). At summary
    judgment, district courts should not determine whether a
    particular phrasing is a scrivener’s error when other
    possibilities are reasonable. See, e.g., Coffill v. Coffill,
    
    656 F.3d 93
    , 95–96 (1st Cir. 2011) (holding that it was
    error to rule that a purported scrivener’s error existed
    “without evidentiary hearing and evidentiary basis”). We
    agree with the District Court that, in the context of the
    correspondence in the record and the surrounding
    sentences, it would be unreasonable or absurd to read that
    sentence in the 1966 letter as a concession that NUMEC
    considered the roof “unrestricted.” The same paragraph
    explains the unrestricted areas were at the “roof edge”:
    “[T]he roof edge air samplers are measuring directly the
    concentration being discharged to unrestricted areas.”
    JA5317.
    36
    Ultimately, we defer to the expertise of the NRC as
    to where the restricted area of the Apollo facility ended.
    In 1995, the NRC issued a report investigating another
    NUMEC facility in Parks, Pennsylvania. 
    60 Fed. Reg. 35,571
    , 35,573 (1995). Even though the report was about
    the Parks facility, the NRC referred to the 1969 letter that
    allowed NUMEC to exceed regulatory limits at the
    Apollo facility’s stacks. The NRC stated that, despite a
    1969 license amendment setting limits for stack
    emissions, the regulatory limits were set at the boundary
    of the roof. “Accordingly, even though NUMEC was
    authorized to discharge at the stack up to 100 times the
    value specified in Appendix B, Table II, [under a 1969
    license amendment,] NUMEC was still required to meet
    the limits at the site boundary (see footnote 8).” 
    Id.
    Footnote 8, in turn, stated, “The values set forth in 10
    CFR Part 20, Appendix B, Table II, are the regulatory
    limits applicable at the site boundary, not at the stack.”
    Id. at 35,573 n.8.
    Under Auer v. Robbins, 
    519 U.S. 452
    , 461–62
    (1997), we defer to the NRC’s “fair and considered
    judgment” of its interpretation of its regulation. One
    could argue that the NRC should receive less deference
    to the extent that the NRC’s 1995 position conflicts with
    Plaintiffs’ historical evidence. In this case, we believe
    we still owe full deference. The Supreme Court’s main
    concern with an agency switching positions has been
    with circumstances in which the new position could
    cause “unfair surprise.” Long Island Care at Home, Ltd.
    37
    v. Coke, 
    551 U.S. 158
    , 170–71 (2007) (“[A]s long as
    interpretive changes create no unfair surprise[,] . . . the
    change in interpretation alone presents no separate
    ground for disregarding the Department’s present
    interpretation.”). Here, our Auer deference would not
    harm any reliance interests.
    Even if we did not defer to the NRC, Defendants’
    interpretation of a “restricted area” is more consistent
    with our precedent than is Plaintiffs’ functional
    argument. In 1995, we held that “[t]he definitions of
    ‘restricted’ and ‘unrestricted areas’ demonstrate that the
    C.F.R. sections governing persons in ‘unrestricted areas’
    were intended to cover persons outside a nuclear plant’s
    boundaries, i.e., the general public.” In re TMI, 
    67 F.3d at 1114
     (footnote omitted). Although denial of access to
    the “general public” alone does not turn a space into a
    restricted area, our understanding has been focused more
    on whether a licensee exercises control rather than on the
    precise safety measures chosen by the licensee. Other
    than the isolated statements by NUMEC, Plaintiffs give
    us no reason to believe that more than locked hatches
    were needed to control access to the roof for purposes of
    protecting individuals from radiation.
    B. The License Did Not Create a Duty
    As noted above, in 1969, the AEC approved
    NUMEC’s request to amend its license to allow “the
    discharge of radioactive material from any stack . . . in
    concentrations up to one-hundred (100) times the
    38
    applicable limits specified in Appendix B, Table II,”
    contingent on satisfactory sampling “at the plant roof
    perimeter” and “in the neighboring unrestricted areas of
    [the] plant.” JA5112. Plaintiffs argue that this 1969
    license amendment now creates a tort duty that
    Defendants violated by discharging more than 100 times
    the maximum permissible concentration at the stacks.
    In a Price-Anderson public liability claim, “federal
    law preempts state tort law on the standard of care.” In
    re TMI, 
    67 F.3d at 1107
    . Our 1995 opinion in In re TMI
    instructs that the duty that survives preemption must be a
    regulatory requirement meant to protect people like
    Plaintiffs. Following In re TMI, we look to the principles
    of negligence per se (by analogy) and to other courts’
    interpretation of duty under the Price-Anderson Act.
    Because this license requirement was only meant to make
    it easier to assess whether NUMEC violated 
    10 C.F.R. § 20.106
     at the boundary of the restricted area—not to
    create an independent obligation—we hold this license
    requirement does not supply a tort duty.
    In the 1995 TMI case, plaintiffs argued that the “as
    low as is reasonably achievable” principle (“ALARA”)
    established the tort duty. This Court held instead that 
    10 C.F.R. §§ 20.105
    , 106 established the relevant duty. Two
    of our major considerations were that (1) §§ 20.105 and
    20.106 indicated they should apply to effluent emissions
    to the public, In re TMI, 
    67 F.3d at 1114
    , and (2) the
    ALARA regulation states that it was not “to be construed
    39
    as radiation protection standards” but was rather meant to
    be a discretionary tool for regulatory agencies, 
    id.
     at
    1114–15 (internal quotation mark omitted). Thus, we see
    that our concerns in 1995 reflected (1) whether the
    regulation was meant to cover the persons allegedly
    affected and (2) whether the regulation was meant to
    establish actual standards or operating principles for the
    agency. These same considerations are not present here.
    The limitations on the stacks were meant to show levels
    below which there could not be a violation at the
    boundary. Thus, they were not directly protective of
    persons in unrestricted areas and were a discretionary
    choice by the AEC to make policing NUMEC easier.
    The 1995 TMI case also instructs us to consider
    principles from negligence per se. In that case, we
    explained that the duty analysis under the Price-Anderson
    Act “is analogous to the practice followed by many
    jurisdictions with negligence per se cases. In such cases,
    where defendants violated the relevant statute or
    regulation, courts have held as a matter of law that
    plaintiffs have satisfied the first two elements of their
    cause of action: the duty and breach of duty.” In re TMI,
    
    67 F.3d at 1118
    .
    Plaintiffs’ objection that we would nullify the
    license requirements if we refused to use them as the
    40
    standard of care18 assumes that every legal requirement
    must be enforceable by a civil plaintiff. That assumption
    is contrary to fundamental principles of negligence per
    se, under which courts must ask “whether the policy
    behind the legislative enactment will be appropriately
    served by using it to impose and measure civil damage
    liability.” Frederick L. v. Thomas, 
    578 F.2d 513
    , 517 n.8
    (3d Cir. 1978).
    Negligence per se only attaches to a statutory or
    administrative duty when its direct effect is to prevent the
    harm at issue to the type of person allegedly injured. See
    Byrne v. Matczak, 
    254 F.2d 525
    , 528 (3d Cir. 1958)
    (“[T]he general principle is that the violation of a statute
    will not create a liability unless it is the efficient cause of
    the injury.”); Congini ex rel. Congini v. Portersville
    Valve Co., 
    470 A.2d 515
    , 518 (Pa. 1983); Restatement
    (Second) Torts § 286.19 We have held that “general
    18
    “To hold that NUMEC had no duty to obey the AEC’s
    regulatory caps stated in its license would be tantamount
    to holding that the AEC had no authority to set those
    limits.” Pls.’ Br. 35.
    19
    When we adopted 
    10 C.F.R. §§ 20.105
     and 20.106 as
    the standard of care, we cited Restatement (Second) of
    Torts for the proposition that a court can adopt
    regulations as the standard of care. See In re TMI, 
    67 F.3d at
    1113 n.24.
    41
    licensing or permit schemes do not usually establish
    standards of competence; they do not usually represent
    judgments that a violation of the licensing scheme will
    generally constitute the breach of a duty to a particular
    person rather than to the state.” Beaver Valley Power
    Co. v. Nat’l Eng’g & Contracting Co., 
    883 F.2d 1210
    ,
    1221–22 (3d Cir. 1989); see also Talley v. Danek Med.,
    Inc., 
    179 F.3d 154
    , 159 (4th Cir. 1999) (“Even if the
    regulatory scheme as a whole is designed to protect the
    public or to promote safety, the licensing duty itself is not
    a standard of care, but an administrative requirement.”);
    Restatement (Second) of Torts § 288 (“The court will not
    adopt as the standard of conduct . . . the requirements
    of . . . administrative regulation whose purpose is found
    to be exclusively . . . to protect the interests of the state or
    any subdivision of it as such.”).20
    20
    Following oral argument, Plaintiffs filed a letter under
    Rule 28(j) of the Federal Rules of Appellate Procedure
    with additional cases that showed regulations creating
    tort duties. None of them is contrary to the reasoning
    above. Rather, Plaintiffs’ 28(j) cases pertain to situations
    in which statutes explicitly create a duty for license
    violations, see 
    33 U.S.C. § 1365
    (a) (“[A]ny citizen may
    commence a civil action on his own behalf . . . against
    any person . . . who is alleged to be in violation of . . . .
    an effluent standard.”); 
    33 U.S.C. § 1365
    (f) (“[T]he term
    ‘effluent standard or limitation under this chapter’
    42
    Finally, as in 1995, we look to other circuits’
    caselaw as “instructive.” In re TMI, 
    67 F.3d at 1113
    .
    Here, we see that no other circuit has adopted Plaintiffs’
    proposed standard. See Adkins v. Chevron Corp., 
    960 F. Supp. 2d 761
    , 766, 772–73 (E.D. Tenn. 2012) (holding
    that license violations do not create duty in a Price-
    Anderson public liability action).
    The history of the license amendment shows that
    its purpose was not to create an independent duty to
    minimize discharge from the stacks. On November 13,
    1968, Roger D. Caldwell, NUMEC Manager, Health and
    Safety, sent a letter to Donald A. Nussbaumer at the
    AEC. The letter requested a change to NUMEC’s license
    that would “permit[] concentrations up to 100 MPCa in
    any stack’s effluent, providing the concentration at the
    roof edge is permissible.” JA5073. Caldwell justified
    means . . . a permit or condition thereof . . . .”); 
    N.Y. Veh. & Traffic Law § 509
    (3) (“Whenever a permit or
    license is required to operate a motor vehicle, no person
    shall operate any motor vehicle in violation of any
    restriction contained on, or applicable to, the permit or
    license.”), or situations where preemption of alternative
    laws is not as complete as here, see Gomez v. St. Jude
    Medical Daig Div. Inc., 
    442 F.3d 919
    , 928–30 (5th Cir.
    2006) (discussing the scope of preemption relating to the
    Medical Device Amendments).
    43
    the request by pointing to empirical data relating to
    diffusion factors at the Apollo facility—that is, by
    showing that amounts released at the stacks would be
    much less at the roof edge. See JA5074–76.
    On February 5, 1969, Lawrence D. Low, AEC,
    Director, Division of Compliance wrote to Zalman
    Shapiro, NUMEC President. Low wrote that “the
    concentrations of radioactive material released from the
    facility through exhaust stacks to unrestricted areas
    exceed the limits . . . contrary to 10 CFR 20.106(a).”
    JA5079–80. In the same section of the letter, Low
    acknowledged NUMEC’s request that its license “be
    amended to permit use of a dilution factor for stack
    effluents.” JA6080.
    On February 25, 1969, Shapiro responded,
    explaining that a higher concentration limit could be
    applied at the stacks to determine whether NUMEC
    violated its maximum permissible concentration at the
    roof edge:
    We recognize the necessity for an
    amendment to our license which would
    reflect appropriately the means of varifying
    [sic] the effectiveness of atmospheric
    dilution in reducing concentration in
    unrestricted areas. In this connection, we
    submitted on November 13, 1968 a request
    for an amendment to our license which
    would place primary reliance on roof
    44
    perimeter sampling in lieu of stack sampling
    as a means of measuring releases to
    unrestricted areas. At a meeting on January
    17, 1969 with Licensing and Compliance
    personnel, it was concluded that the off-site
    environment sampling program should be
    included as a part of our license amendment
    application to provide additional assurance
    with respect to the effectiveness of
    atmospheric dilution. Accordingly, we are
    preparing and will submit by March 7, 1969
    a revised application which, if approved,
    should provide an acceptable means of
    varifying [sic] compliance with Part 20.
    JA5083–84.
    On March 10, 1969, Caldwell submitted a “revised
    application to permit concentration to 100 MPCa in any
    stack’s effluent.” JA5087. Again, Caldwell “justified”
    the proposed limits by pointing to empirical data showing
    dilution factors at the roof perimeter. 
    Id.
    On May 26, 1969, Nussbaumer at the AEC wrote
    to Caldwell at NUMEC granting the amendment to
    NUMEC’s license “to authorize the discharge of
    radioactive material from any stack effluent . . . in
    concentrations up to one-hundred . . . times the
    applicable limits . . . in accordance with the statements,
    representations and conditions specified in your
    application dated March 5, 1969.” JA5112 (emphasis
    45
    added).      Nussbaumer added, “We consider the
    environmental sampling program required by Condition
    2 above to be a means for providing backup data and
    evidence that your roof edge sampling results are
    adequately representative of the concentrations released
    to the unrestricted areas.” JA5112–13 (emphasis added).
    Thus, even at the time, the AEC, via Nussbaumer,
    accepted NUMEC’s “representations” about the
    relationship between the stack discharges and the roof
    edge and that the roof edge monitors would be used to
    determine the concentrations “released to the unrestricted
    areas.”
    In 1995, the NRC agreed that NUMEC’s purpose
    in seeking the amendment assumed that all requirements
    would be met if the emission at the boundaries were
    below the maximum permissible concentration: “By
    application dated November 13, 1968, and supplement
    dated March 5, 1969, and pursuant to 10 CFR 20.106(b),
    NUMEC requested that License SNM-145 be amended to
    permit concentrations up to 100 times the limits specified
    in Part 20, Appendix B, Table II, in any stack effluent,
    provided that concentrations at the roof edge and in the
    local environment complied with 10 CFR Part 20 limits.”
    In re Babcock & Wilcox Co., 
    41 N.R.C. 489
    , 492–93
    (June 26, 1995); see also 
    10 C.F.R. § 20.106
    (b). Thus, it
    is clear that the stack-discharge license restriction was
    created as a threshold to test for emissions at the
    boundary of the restricted area.
    46
    Because the license requirement was only an
    administrative safe harbor for NUMEC’s compliance
    with the emissions maximum set at the boundary of the
    restricted area, it does not create a tort duty here.
    C. Plaintiffs Had to Show that Maximum Permissible
    Concentration was Exceeded on Average Over a Full
    Year
    Section 20.106 states, “For purposes of this
    section[,] concentrations may be averaged over a period
    not greater than one year.” 
    10 C.F.R. § 20.106
    (a) (1980).
    The District Court’s holding that Plaintiffs failed to show
    a genuine issue of material fact regarding duty was based
    on Plaintiffs’ failure to show a violation of § 20.106
    when averaged over the course of a year: “Plaintiffs
    have pointed to no genuine issues of material fact that the
    annual average concentration of uranium effluent ever
    exceeded 1.7 x 10-2 microcuries/milliliter during the
    period 1957–1960, or that it ever exceeded 4.0 x 10-12
    microcuries/milliliter during the period 1961–1983.”
    McMunn, 131 F. Supp. 3d at 388. On appeal, Plaintiffs
    continue to argue that they could show a violation based
    on a discharge that exceeds the maximum permissible
    concentration over any length of time. Plaintiffs are
    plainly wrong.
    Plaintiffs’ argument is based entirely on the word
    “may” in the phrase “concentrations may be averaged
    over a period not greater than one year.” They argue,
    “The term may is permissive, not mandatory. There is no
    47
    requirement to take an average.” Pls.’ Br. 43 (footnote
    omitted). We agree with Plaintiffs that “may” is
    permissive. See, e.g., Simpson v. Kay Jewelers, Div. of
    Sterling, Inc., 
    142 F.3d 639
    , 650–51 (3d Cir. 1998)
    (comparing “the more flexible and permissive ‘may’” to
    “the mandatory ‘must’” (quoting Torre v. Casio, Inc., 
    42 F.3d 825
    , 831 n.6 (3d Cir. 1994))).
    But Plaintiffs’ reliance on a single word in that
    phrase ignores the fact that it is part of a sentence that
    speaks in the passive voice. “Phrases constructed in the
    passive voice use an implied subject or actor who carries
    out the verb.” Sci. Drilling Int’l, Inc. v. Pathfinder
    Energy Servs., Inc., No. H-06-1634, 
    2006 WL 2882863
    ,
    at *3 (S.D. Tex. Oct. 4, 2006). Thus, the question is who
    has the discretion to decide whether to average annually.
    Given the context of the regulation, the obvious
    answer is that such discretion lies in the AEC because it
    is the entity charged with determining whether a licensee
    violates its regulatory duties. Cf. United States v.
    Brumbaugh, 
    909 F.2d 289
    , 291 (7th Cir. 1990) (“The use
    of the passive voice in the statutory language requires us
    to infer a subject; the most logical inference is that the
    Attorney General, who has been charged with granting
    credit under section 3568 for over thirty years, is the
    intended subject of the sentence.”). Plaintiffs’ unwritten
    assumption that the AEC intended for tort plaintiffs or
    district courts to have discretion to use annual averaging
    is mistaken. Giving tort plaintiffs the power to determine
    48
    retroactively the period over which a violation is assessed
    “would allow [them] to fix the standard case by case and
    plant by plant. An operator acting in the utmost good
    faith and diligence could still find itself liable for failing
    to meet such an elusive and undeterminable standard.”
    In re TMI, 
    67 F.3d at 1115
    . Under § 20.106, Plaintiffs
    were required to show a breach using annual averaging.
    Their data relating to individual moments in time fails to
    show a breach.
    ***
    Plaintiffs’ attempts to expand Defendants’ duty
    must fail. The maximum permissible concentration is
    assessed at the boundary of the roof, the license
    requirement does not create a duty, and Plaintiffs must
    show that the maximal permissible concentration was
    exceeded when the emissions are averaged annually.
    II. BREACH
    The District Court held that Plaintiffs failed to
    show there was a dispute of fact as to whether
    Defendants emitted excessive radiation at the boundary
    of the roof because Plaintiffs failed to offer appropriate
    expert testimony.21 On appeal, Plaintiffs again rely
    21
    See McMunn, 131 F. Supp. 3d at 389 (“In addition, to
    establish a breach of duty, Plaintiffs must offer evidence
    49
    almost entirely on data from the stacks and roof fans,
    which, as was established above, are legally irrelevant.
    See, e.g., Pls.’ Reply Br. 15–16 (“NUMEC officials were
    all too aware of the problem with the roof fans.”).
    Putting aside the stacks and fans data, we agree that
    Plaintiffs’ argument for breach fails for lack of expert
    evidence in this highly technical area.
    Moreover, Plaintiffs argue that they are “entitled”
    to “adverse inferences” that allow them to show a breach
    (and also causation). See Pls.’ Br. 22. This, too, fails
    because Plaintiffs did not show that the District Court
    abused its discretion in denying the adverse inference.
    A. Plaintiffs Needed Experts
    Plaintiffs failed to provide an expert who could
    testify that the data upon which they rely (stacks, vents,
    and readings from outside the facility) could show a
    violation of the maximum permissible concentration of
    uranium effluent at the boundary of the roof when
    averaged annually.
    Expert evidence is generally required when an
    issue is beyond the ken of a lay jury. For instance, in a
    medical monitoring claim, we explained that the plaintiff
    from a qualified expert that the Apollo facility’s
    emissions exceeded regulatory limits.”).
    50
    had to prove he or she suffered a “significantly increased
    risk of contracting a serious latent disease” and other
    factors “by competent expert testimony.” Redland
    Soccer Club, Inc. v. Dep’t of Army of U.S., 
    55 F.3d 827
    ,
    845–46, 852 (3d Cir. 1995).22 Similarly, then-Judge
    Sotomayor wrote for the Second Circuit that expert
    testimony would be “necessary” where “an injury has
    multiple potential etiologies.” Wills v. Amerada Hess
    Corp., 
    379 F.3d 32
    , 46 (2d Cir. 2004).
    22
    Cf. also Boring v. Kozakiewicz, 
    833 F.2d 468
    , 473 (3d
    Cir. 1987) (“In some situations in which the seriousness
    of injury or illness would be apparent to a lay person,
    expert testimony would not be required, e.g., a gunshot
    wound. However, those circumstances are not present
    here.” (citation omitted)); Breidor v. Sears, Roebuck &
    Co., 
    722 F.2d 1134
    , 1140–41 (3d Cir. 1983) (stating that
    expert testimony was necessary to rebut the defendants’
    contention in a products liability case); Lentino v. Fringe
    Emp. Plans, Inc., 
    611 F.2d 474
    , 480 (3d Cir. 1979)
    (“Expert testimony is required to establish the relevant
    standard and whether the defendant complied with that
    standard, except where the matter under investigation is
    so simple, and the lack of skill so obvious, as to be within
    the range of the ordinary experience and comprehension
    of non-professional persons.” (citations omitted)
    (Pennsylvania medical malpractice case)).
    51
    Perhaps recognizing their failure to transmute vent
    data into roof data, Plaintiffs try to borrow an “average
    dilution factor of 50” from an isolated 1968 document.
    See Pls.’ Br. 45. But these kinds of calculations are best
    suited to experts—not lawyers or lay factfinders.
    B. The District Court Did Not Abuse Its Discretion in
    Holding That Plaintiffs Were Not Entitled to an
    Inference Sufficient to Survive Summary Judgment
    Objecting to the report and recommendation,
    Plaintiffs argued that Defendants’ poor recordkeeping
    allowed them to request an inference under which a jury
    could assume that Defendants had breached the above-
    described duty. [See Dist. Ct. ECF No. 376, at 50–53.]
    By adopting the Magistrate Judge’s report and
    recommendation, the District Court rejected this
    argument. See McMunn, 131 F. Sup. 3d 352.
    We review the District Court’s denial of the
    adverse inference for abuse of discretion. See, e.g., In re
    Hechinger Inv. Co. of Del., Inc., 
    489 F.3d 568
    , 574 (3d
    Cir. 2007) (“We also review the [bankruptcy court’s]
    denial of UFP's motion seeking an evidentiary inference
    based on spoliation of evidence for abuse of discretion.”);
    Davis v. White, 
    858 F.3d 1155
    , 1160 (8th Cir. 2017)
    (“The district court’s refusal to sanction the officers with
    an adverse inference instruction was not an abuse of
    discretion.”).
    52
    Plaintiffs have failed to show that the District
    Court abused its discretion when determining that an
    adverse inference was not warranted here.23 Plaintiffs
    simply have not developed their argument sufficient to
    show an abuse of discretion. [See Pls.’ Br. 21–22.] In
    cases where this argument is more developed, an adverse
    inference may be appropriate. See United States ex rel.
    Scutellaro v. Capitol Supply, Inc., No. 10-1094 (BAH),
    
    2017 WL 1422364
    , at *11 (D.D.C. Apr. 19, 2017)
    (noting several circuits have held that the failure to
    maintain records allows for an adverse inference). This
    can be seen by analogy to spoliation cases. In spoliation
    cases, where there is evidence that one party has
    destroyed or altered evidence, the opposing party can
    obtain a “‘spoliation inference,’ that the destroyed
    evidence would have been unfavorable to the position of
    the offending party.” Schmid v. Milwaukee Elec. Tool
    Corp., 
    13 F.3d 76
    , 78 (3d Cir. 1994). Here, because
    23
    Plaintiffs’ recordkeeping argument also relates to their
    failure to provide expert evidence relating to any
    individual Plaintiff’s exposure. See, e.g., Pls.’ Reply Br.
    18 (“NUMEC’s failure to collect data makes calculations
    impossible—and it should not now benefit from its own
    malfeasances.”). Plaintiffs have also failed to show the
    District Court abused its discretion when it denied an
    adverse inference with regard to causation.             See
    McMunn, 131 F. Supp. 3d at 394–96.
    53
    Plaintiffs failed to show an abuse of discretion, we need
    not analyze further.
    III. CAUSATION
    The District Court held that Plaintiffs’ case also
    must be dismissed because Plaintiffs’ experts failed to
    provide “evidence of [Plaintiffs’] exposure to inhaled
    uranium from the Apollo plant and an estimate of the
    dose they received which caused their cancers.”
    McMunn, 131 F. Supp. 3d at 399. On appeal, Plaintiffs
    argue they showed causation even though they did not
    show a dose for any individual plaintiff because (1)
    Plaintiffs needed only to show “frequency, regularity,
    and proximity”—not dose—and (2) the law of the case
    requires us to assume that Melius’s testimony would be
    sufficient to show causation because the District Court
    ruled Melius’s testimony was admissible in its Daubert
    motion. These arguments are unpersuasive because
    Plaintiffs’ experts failed to show that any of the
    individual Plaintiffs had sufficient exposure—looking at
    the frequency, regularity, and proximity to the
    radiation—and Plaintiffs were not prejudiced by the
    District Court’s inconsistent reasoning.
    A. Plaintiffs Do Not Show Sufficient Frequency,
    Regularity, and Proximity
    Unlike with duty and breach discussed above,
    causation for Price-Anderson public liability actions is
    evaluated under state law. See In re TMI, 
    67 F.3d 1103
    ,
    54
    1117 n.33 (3d Cir. 1995) (“As we have noted, the 1988
    Amendments retroactively required the applicable law
    for ‘public liability actions’ be ‘the law of the State in
    which the nuclear incident involved occurs, unless such
    law is inconsistent’ with federal law.”); see also In re
    Hanford Nuclear Reservation Litig., 
    534 F.3d 986
    , 1010
    (9th Cir. 2007) (“Under the PAA, Washington state law
    controls the standard of causation to be used in this
    case.”). Here, that state law is Pennsylvania law.
    Pennsylvania requires a plaintiff to show that a
    defendant’s acts were a substantial factor in causing a
    plaintiff’s injury. As the Pennsylvania Supreme Court
    recently stated, “To establish proximate causation, a
    plaintiff must adduce evidence to show that the
    defendant’s act was a substantial factor in bringing about
    the plaintiff’s harm.” Rost v. Ford Motor Co., 
    151 A.3d 1032
    , 1049 (Pa. 2016); see also Summers v. Certainteed
    Corp., 
    997 A.2d 1152
    , 1164–65 (Pa. 2010) (“[T]he
    requirements of proving substantial-factor causation
    remain the same.”).
    Until recently, the Pennsylvania Supreme Court
    had suggested that proving substantial-factor causation
    required showing the dose to which plaintiff was exposed
    because otherwise the “substantiality” of the substantial
    factor would not be shown to the jury. See Betz v.
    Pneumo Abex LLC, 
    44 A.3d 27
    , 58 (Pa. 2012)
    (“Certainly a complete discounting of the substantiality
    55
    in exposure would be fundamentally inconsistent with
    Pennsylvania law.”).
    However, following oral argument in the case
    before us, the Pennsylvania Supreme Court issued its
    decision in an asbestos case, Rost v. Ford Motor Co. In
    Rost, the Pennsylvania Supreme Court retreated from its
    earlier statements, emphasizing that it had previously
    “adopted the ‘frequency, regularity, and proximity’ test,
    as refined and applied by the United States Court of
    Appeals for the Seventh Circuit in Tragarz v. Keene
    Corp., 
    980 F.2d 411
     (7th Cir. 1992).” Rost, 151 A.3d at
    1043.
    It may well be that Rost applies only in
    mesothelioma cases because of unique public policy
    concerns about mesothelioma.24 Yet we need not decide
    24
    See, e.g., Rost, 151 A.3d at 1042–43 (describing the
    “test on motions for summary judgment in mesothelioma
    cases”); id. at 1044 n.7 (“It is important to recognize that
    this Court settled on these principles based on a policy
    concern: that it is fundamentally unfair to hold a
    defendant jointly and severally liable for a mesothelioma
    plaintiff’s injuries for a de minimis contribution to the
    plaintiff’s overall exposure.”); id. at 1052 (stating that the
    frequency, regularity, and proximity test applied “for all
    exposures to asbestos”). This makes particular sense to
    the extent that Rost relies on Tragarz, which, in turn is
    56
    based on an Illinois appellate court’s reliance on the
    nature of asbestos-related diseases:
    Given the various diseases which are
    associated with asbestos exposure, the
    medical evidence presented, the types of
    asbestos involved, the manner in which the
    products are handled, and the tendency of
    those asbestos products to release asbestos
    fibers into the air, the amount of evidence
    needed to establish the regularity and
    frequency of exposure will differ from case
    to case. For example, none of the plaintiffs
    in this case were diagnosed with
    mesothelioma, an asbestos-related disease
    which is caused after only minor exposure to
    asbestos dust.
    Wehmeier v. UNR Indus., Inc., 
    572 N.E.2d 320
    , 337 (Ill.
    App. Ct. 1991) (citation omitted).
    Mesothelioma is a “signature” disease relating to
    asbestos exposure; individuals do not usually develop
    mesothelioma without asbestos exposure. See Daley v.
    A.W. Chesterton, 
    37 A.3d 1175
    , 1177 n.4 (Pa. 2012)
    (“Moreover, because mesothelioma, in general, is so rare,
    ‘any case occurring after a well attested and substantial
    asbestos exposure is commonly accepted as being caused
    57
    by that exposure.’”); see also Ford Motor Co. v. Boomer,
    
    736 S.E.2d 724
    , 728 (Va. 2013) (“Mesothelioma is a
    signature disease: it was uncontroverted at trial that the
    cause of mesothelioma is exposure to asbestos at some
    point during an individual's lifetime.”).
    By contrast, the cancers suffered by the Plaintiffs have
    numerous and sometimes even unknowable causes, as
    Melius conceded. See JA3236 (“We're evaluating a
    disease that’s multi-causal. We don’t have any way of
    testing the cancer to determine what caused it, what
    specific factor caused it.”); JA3237 (“There are many
    cancers that occur where we don’t identify the cause of
    that cancer or the causes of that cancer.”); JA3311 (“In
    an individual patient I think it’s more appropriate to use
    risk factors because it implies -- otherwise it implies that
    we know the factor that caused their specific individual
    cancer and in most cases we probably do not.”); see also
    Risk Factors for Cancer, Nat’l Cancer Institute,
    https://www.cancer.gov/about-cancer/causes-
    prevention/risk (last visited Oct. 15, 2016) (identifying
    age, alcohol, cancer-causing substances, chronic
    inflammation, diet, hormones, immunosuppression,
    infectious agents, obesity, radiation, sunlight, and
    tobacco as risk factors for cancer).
    Indeed, in 1999, we explained that establishing causation
    for a given cancer was extremely difficult. See In re TMI
    58
    whether Rost is limited to mesothelioma cases because
    Plaintiffs’ evidence would not allow a jury to find
    sufficient frequency, proximity, and regularity. Rost
    requires a plaintiff at summary judgment to have
    propounded “evidence that exposure to defendant’s
    asbestos-containing product was sufficiently ‘frequent,
    regular, and proximate’ to support a jury’s finding that
    defendant’s product was substantially causative of the
    disease.” Rost, 151 A.3d at 1044 (emphasis added). For
    Litig., 
    193 F.3d at 643
     (“Consequently, medical
    evaluation, by itself, can neither prove nor disprove that a
    specific malignancy was caused by a specific radiation
    exposure.”). Modern secondary sources continue to
    agree with that assessment. See, e.g., Steve C. Gold,
    When Certainty Dissolves into Probability: A Legal
    Vision of Toxic Causation for the Post-Genomic Era, 
    70 Wash. & Lee L. Rev. 237
    , 279–81 (2013); William D.
    O’Connell, Note, Causation’s Nuclear Future: Applying
    Proportional Liability to the Price-Anderson Act, 
    64 Duke L.J. 333
    , 357, 359 (2014) (“Radiation-protection
    scientists are in agreement that differential diagnosis
    cannot confidently identify the ultimate source of a
    plaintiff’s cancer.”); cf. Wilcox v. Homestake Mining Co.,
    
    619 F.3d 1165
    , 1167 (10th Cir. 2010) (“[N]or do we see
    a basis for alternative liability where only one potential
    wrongdoer has been identified and the injury may simply
    have resulted from natural causes.”).
    59
    instance, the Rost Court noted that the plaintiff’s expert
    testified to more than three months of exposure “while
    noting studies showing that a single month of regular
    exposure to asbestos can double one’s likelihood of
    developing mesothelioma.”        Id. at 1046.        Even
    Lohrmann—the original frequency, regularity, and
    proximity case, which stated that the court was creating
    “a de minimis rule” for proving asbestosis causation
    under Maryland law—explained that “a plaintiff must
    prove more than a casual or minimum contact with the
    product.” Lohrmann v. Pittsburgh Corning Corp., 
    782 F.2d 1156
    , 1162 (4th Cir. 1986). Here, where Plaintiffs
    (1) simply rely on the existence of any frequency,
    regularity, and proximity and (2) fail to offer any
    individualized evidence of exposure for any given
    Plaintiff, they come up short. Even were this evidence
    substantively permissible under Pennsylvania law, it
    would fail to be admissible under Daubert for three
    reasons.
    First, Melius’s testimony is insufficient to create a
    genuine issue of fact regarding causation because it is
    nothing more than a radiation version of the
    impermissible “any breath” theory in Gregg v. V-J Auto
    Parts (the case in which that court first adopted the
    frequency, regularity, and proximity test in mesothelioma
    cases). See Summers, 997 A.2d at 1161 n.14 (“In Gregg
    v. V-J Auto Parts, Co., 
    596 Pa. 274
    , 
    943 A.2d 216
    (2007), this Court recently rejected the viability of the
    ‘each and every exposure’ or ‘any breath’ theory.”). The
    60
    Gregg Court explained that, in a so-called “any breath”
    theory of asbestos exposure, a plaintiff alleges that “any
    exposure to asbestos, no matter how minimal, is a
    substantial contributing factor in asbestos disease.”
    Gregg v. V-J Auto Parts, Co., 
    943 A.2d 216
    , 226 (Pa.
    2007); see also Howard v. A.W. Chesterton Co., 
    78 A.3d 605
    , 608 (Pa. 2013) (per curiam) (“Bare proof of some de
    minimus [sic] exposure to a defendant’s product is
    insufficient to establish substantial-factor causation for
    dose-responsive diseases.”).
    Melius assumes that anyone who lived in the area
    of the Apollo facility was exposed to a sufficient amount
    of radiation. In Melius’s words, he “estimated that -- that
    they had a, um, substantial or significant exposure.”
    JA3227. Yet he did not “estimate a specific or associate
    a specific level of exposure with a -- with those terms.”
    
    Id.
     When asked about “significant exposure,” Melius
    agreed that “any exposure to a plaintiff that was above
    that plaintiff’s background would be a substantial
    exposure.” JA3315.25 Similarly, Melius said that,
    25
    This is in contradiction to, for instance, his admissions
    that he relied on different levels of cigarette usage to
    determine substantiality. See JA3300, 3308; see also
    JA3321 (“For cigarette smoking and lung cancer, it is
    reduced to ten or twenty percent increased risk compared
    to somebody who has never smoked after a period of say
    twenty years, maybe even after ten or fifteen years.”).
    61
    “[d]epending on how you use the meaning of
    significant,” he “would say” one millirem above
    background was “substantial.” JA3315–16.
    Second, Melius failed to offer individualized
    testimony as he was required to do for each Plaintiff. For
    instance, in Howard v. A.W. Chesterton Co., the
    Pennsylvania Supreme Court explained, “Relative to the
    testimony of an expert witness addressing substantial-
    factor causation in a dose-responsive disease case, some
    reasoned, individualized assessment of a plaintiff’s or
    decedent’s exposure history is necessary.” 78 A.3d at
    608; cf. also Black v. M&W Gear Co., 
    269 F.3d 1220
    ,
    1237–38 (10th Cir. 2001) (holding that a district court
    did not abuse its discretion in excluding an expert’s
    testimony when that expert “had not based his conclusion
    on the results of tests or calculations specific to” the
    plaintiff). Although Melius describes each Plaintiff’s
    smoking history and a few other features for most
    Plaintiffs, Melius fails to offer any “reasoned . . .
    assessment” of any individual’s exposure to radiation
    from uranium effluent. See, e.g., JA4782–84 (relying on
    reports about radiation released from the facility that do
    not show exposure to any of the individual Plaintiffs).
    He merely offers the conclusion that each Plaintiff’s
    “exposures to uranium and other radioactive materials
    released from the Apollo nuclear facility made a
    significant contribution to the development of” her or his
    cancer. E.g., JA3448. Even if such a conclusion were
    permissibly individualized, it would still be insufficient
    62
    to generate a genuine issue of fact because, under the
    Lone Pine order, only exposure to uranium is at issue
    here.
    Although Rost stresses that causation is an issue
    for the jury, we have never hesitated to grant summary
    judgment where one side fails to establish a genuine issue
    of fact concerning causation. See, e.g., In re TMI Litig.,
    
    193 F.3d 613
    , 722–23 (3d Cir. 1999) (affirming summary
    judgment where plaintiff’s expert testimony “was
    insufficient to create a genuine issue of material fact”
    regarding causation); Heller v. Shaw Indus., Inc., 
    167 F.3d 146
    , 150 (3d Cir. 1999) (“[B]ecause the District
    Court did not abuse its discretion in excluding the key
    elements of Heller’s experts’ testimony necessary to
    prove causation, the grant of summary judgment will be
    affirmed.”).
    Finally, the Federal Rules of Evidence impose a
    duty on a district judge to act as a gatekeeper of expert
    testimony even when considering elements of a cause of
    action derived from state law. See Forrest v. Beloit
    Corp., 
    424 F.3d 344
    , 358 n.9 (3d Cir. 2005) (explaining
    that “evidentiary issues in this case are governed by
    federal . . . law” while Pennsylvania substantive law
    affected what facts would be relevant); see also Hendrix
    ex rel. G.P. v. Evenflo Co., Inc., 
    609 F.3d 1183
    , 1193
    (11th Cir. 2010) (“Although the standards for finding
    causation are governed by Florida law, we apply federal
    law to determine whether the expert testimony proffered
    63
    to prove causation is sufficiently reliable to submit it to
    the jury.”); cf. Daubert v. Merrell Dow Pharm., Inc., 
    509 U.S. 579
    , 597 (1993) (“[A] gatekeeping role for the
    judge . . . is the balance that is struck by Rules of
    Evidence . . . .”).
    Thus, even assuming arguendo that Rost
    resuscitated “any breath” causation, Melius’s testimony
    would be too insubstantial to survive Daubert. Melius’s
    testimony provides only a perfunctory narrative for each
    Plaintiff, and an unexplained conclusion that radiation
    was the cause, presumably because each Plaintiff was
    exposed to some radiation. Such conclusory opinions of
    medical causation, even by qualified experts, are
    insufficient to establish causation of cancer by exposure
    to uranium effluent. See Tamraz v. Lincoln Elec. Co.,
    
    620 F.3d 665
    , 671 (6th Cir. 2010) (“Whatever Dr. Carlini
    understood by ‘with a reasonable degree of medical
    certainty,’ the phrase—the conclusion by itself—does not
    make a causation opinion admissible. The ‘ipse dixit of
    the expert’ alone is not sufficient to permit the admission
    of an opinion.” (quoting Gen. Elec. Co. v. Joiner, 
    522 U.S. 136
    , 146 (1997))).
    Although we have held that an expert can offer an
    opinion “absent hard evidence of the level of exposure to
    the chemical in question,” we have only done so where
    an expert could rely “on the temporal relationship and the
    nature of the plaintiff’s complaints.” Heller, 
    167 F.3d at 157
    . This, too, does not require a dose. But it requires
    64
    more than an assumption about the effect of living within
    a mile of the Apollo facility.
    ***
    Consider how a trial would unfold. Plaintiffs
    would present a general causation expert who opines that
    any amount of ionizing radiation could cause cancer.
    Then, Plaintiffs would present Melius who would state
    that each of the Plaintiffs lived or worked near the Apollo
    facility and would therefore be assumed to have been
    exposed to some radiation from airborne uranium
    effluent from the Apollo facility. Melius would then
    presumably testify that he is certain that the additional
    radiation specifically from the airborne uranium was a
    substantial factor in causing the cancer of each of the
    Plaintiffs.26 Finally, the jury would decide whether more
    than a dozen different illnesses suffered by more than
    seventy people were each caused by the radiation from
    the airborne uranium from the Apollo facility.
    How? Without any ability to compare any
    plaintiff’s frequency, proximity, or regularity to any
    evidence showing that a given frequency, proximity, or
    regularity is correlated with any particular increase in
    26
    Plaintiffs would also have to ensure they have
    sufficient testimony relating only to uranium effluent
    under the Lone Pine order.
    65
    risk—let alone the ability to perform the ideal
    comparison between dose and the dose-responsiveness of
    a given illness—the jury would be engaging in rank
    speculation.
    It is true that demanding more than evidence of
    “any exposure” makes it more burdensome for most
    plaintiffs to recover for injuries from radiation. But the
    evidentiary regime that must apply in these cases
    necessarily requires that a jury find radiation was a
    substantial factor in causing a plaintiff’s injury—and
    requires, now, at summary judgment, that we be able to
    hold that a reasonable jury could so find. See Gregg, 
    943 A.2d at
    225–26 (“We appreciate the difficulties facing
    plaintiffs in this and similar settings, where they have
    unquestionably suffered harm on account of a disease
    having a long latency period and must bear a burden of
    proving specific causation under prevailing Pennsylvania
    law which may be insurmountable.”); see also Fed. R.
    Civ. P. 56(a). We can demand no less.
    B. District Court Law of the Case Does Not Bind This
    Court, and, in Any Event, Plaintiffs Were Not
    Prejudiced
    Pointing to the inconsistency between the District
    Court’s Daubert opinion, which suggested Melius’s
    testimony was strong, and the District Court’s opinion
    granting summary judgment to Defendants, which held
    that Melius’s testimony did not create a genuine issue of
    material fact, Plaintiffs argue that the District Court was
    66
    bound to adhere to its Daubert opinion at summary
    judgment. Such concerns are irrelevant where, as here,
    (a) this Court is not bound by the District Court’s
    Daubert opinion and (b) Plaintiff cannot show prejudice.
    Plaintiffs are correct that the District Court’s
    Daubert opinion appears to be inconsistent with its
    summary judgment opinion. The Daubert opinion
    strongly implied that Melius’s testimony would be
    enough to get the case to the jury, holding that his
    testimony should not be excluded because there was
    “enough support in the record for the contention that the
    Plaintiffs’ exposure levels exceeded the normal
    background level.” McMunn v. Babcock & Wilcox
    Power Generation Grp., Nos. 2:10cv143 et al., 
    2014 WL 814878
    , at *14 (W.D. Pa. Feb. 27, 2014). By contrast,
    the District Court’s summary judgment opinion held that
    “Plaintiffs must provide . . . an estimate of the dose they
    received which caused their cancers.” McMunn, 131 F.
    Supp. 3d at 399.
    But, as a general matter, we fail to see what
    difference law of the case makes at this stage of the
    litigation. We are not bound by either of the District
    Court’s rulings, and we have addressed the Plaintiffs’
    arguments on their own merits.
    At all events, Plaintiffs’ law-of-the-case argument
    fails on its own merits. Two values animate law-of-the-
    case doctrine: judicial economy and unfair prejudice.
    See, e.g., Roberts v. Ferman, 
    826 F.3d 117
    , 126 (3d Cir.
    67
    2016) (“We also have held that ‘the law of the case
    doctrine does not limit the power of trial judges to
    reconsider their prior decisions,’ but have noted that
    when a court does so, it must explain on the record why it
    is doing so and ‘take appropriate steps so that the parties
    are not prejudiced by reliance on the prior ruling.’”
    (quoting Williams v. Runyon, 
    130 F.3d 568
    , 573 (3d Cir.
    1997))).
    Here, Plaintiffs have failed to show any prejudice
    from the District Court’s change in position. Had the
    District Court ruled against them in its Daubert order,
    Plaintiffs’ case would have been dismissed as the
    Magistrate Judge recommended. Plaintiffs would not
    have had an opportunity to create new expert reports in
    response to a Daubert ruling that more clearly reflected
    the District Court’s legal rulings on causation at
    summary judgment.
    Perhaps Plaintiffs could have argued that they
    were prejudiced because they were lulled into failing to
    challenge Defendants’ uncontested facts. But, because
    we do not rely on any of those uncontested facts when we
    hold that Plaintiffs fail to show a genuine dispute of
    material fact with regard to causation, not even the
    admission of the uncontested facts demonstrates
    prejudice.
    ***
    68
    Because Plaintiffs failed to offer evidence from
    which a jury could find that each plaintiff was exposed to
    radiation from Defendants’ uranium effluent sufficiently
    frequently, regularly, and proximately to substantially
    cause their illnesses, and further because the law-of-the-
    case doctrine does not require us to conclude otherwise,
    we hold that Defendants have failed to demonstrate
    issues of material fact on causation.
    CONCLUSION
    Defendants are entitled to judgment as a matter of
    law because Plaintiffs failed to show a genuine issue of
    material fact with regard to duty, breach, and causation.
    Therefore, we will affirm the judgment of the District
    Court.
    69
    McMunn, et al. v. Babcock & Wilcox Power Generation
    Group, Inc., et al., No. 15-3506
    MCKEE, Circuit Judge, concurring, joined by RESTREPO,
    Circuit Judge.
    While I agree that summary judgment is appropriate here,
    I write to stress that the law in this area is simply inadequate
    to address claims arising under the Price-Anderson Act based
    on exposure to excess radiation.
    As the Majority explains, this is a Public Liability Action
    under the Price-Anderson Act.1 Federal law therefore
    controls our inquiry into whether Defendants owed Plaintiffs
    a duty, and if so, whether the duty was breached. State law
    controls the inquiry into whether the breach, if proven, caused
    Plaintiffs’ injuries.2 As I will explain, existing law places an
    almost insurmountable burden on plaintiffs who try to recover
    under the Price-Anderson Act. Under the existing law,
    Plaintiffs cannot establish causation, even if they have
    established that Defendants owed them a duty that was
    breached.
    Suits for injuries allegedly resulting from radiation
    exposure have no analogous counterpart in traditional tort
    law, and existing law ignores the unique problems inherent in
    claims based on exposure to “manmade” radiation. As a
    result, plaintiffs will rarely, if ever, recover in these types of
    actions, and this will continue unless states (or Congress)
    recognize the unique problems endemic in proving that a
    plaintiff’s illness was proximately caused by exposure to
    radiation from a given facility or event.
    I. BREACH OF DUTY
    I believe that Plaintiffs’ submissions (as itemized in
    the Majority Opinion) are more than adequate to survive
    Defendants’ motion for summary judgment as to breach of
    duty.3  For example, an internal memorandum, dated
    1
    Maj. Op. at 5.
    2
    See In re TMI, 
    67 F.3d 1103
    , 1117 n.33 (3d Cir. 1995).
    3
    See Maj. Op. at 10-12.
    1
    November 29, 1972, regarding NUMEC’s meeting with AEC
    Compliance stated:
    P. Nelson [AEC personnel] opened by
    explaining the purpose of the meeting. He
    stated that Compliance was concerned about the
    recurring nature and seriousness of NUMEC
    violations. He explained that the AEC could
    now impose civil penalties for those types of
    violations. . . . NUMEC has been the worst
    offender of AEC regulations over the years. .
    . . AEC had given NUMEC a grace period after
    the B&W takeover, but that little improvement
    was evident. The AEC is strongly considering
    imposing civil penalties against NUMEC.4
    Another letter from the AEC stated: “It appears that certain of
    your activities were not conducted in full compliance with . . .
    and the requirements of the AEC’s ‘Standards for Protection
    Against Radiation,’ Part 20, and ‘Special Nuclear Material’ . .
    . .”5 Based on this, there could be enough evidence to support
    Plaintiffs’ claimed breach of duty.
    The Majority affirms the District Court’s conclusion
    that much of Plaintiffs’ evidence is of either limited value or
    irrelevant because the only expert whose testimony survived
    the Daubert motion (Dr. Melius) primarily focused on
    radiation levels at the stacks or vents and not at the roof top
    boundary.6 Although I agree that Plaintiffs must establish the
    levels of radiation at the roof boundary rather than levels at
    the vents or stacks, levels at the vents or stacks could
    nevertheless be very relevant to establishing levels at the
    boundary if that evidence had been properly developed. This
    follows from the fact that different radioactive substances
    have different half-lives. I will not wade into the quantum
    mechanical weeds of half-lives here as that was discussed in
    some detail in our 1999 opinion in In re TMI Litigation (TMI
    II).7 Rather, I will merely note that half-lives vary from as
    short as less than a second to as long as many billions of
    4
    JA4439-40 (emphasis added).
    5
    JA4693.
    6
    See Maj. Op. at 23, 29-34.
    7
    
    193 F.3d 613
     (3d Cir. 1999).
    2
    2
    years, depending on the substance involved.8 Accordingly, if
    byproducts of the uranium produced at Defendants’ facility
    included substances with sufficiently long half-lives, their
    levels at the stacks and vents would be very relevant to
    determining exposure at the roof boundary and beyond. A
    fact finder could readily conclude that the levels at the vents
    and stacks persisted with no discernable diminution (even
    after allowing for dilution as they dispersed into the
    surrounding community) long enough for residents of the
    community to be exposed to those levels. The probative
    value of this evidence could be particularly compelling if the
    effluents that comprise the byproducts of uranium production
    are not otherwise found in the environment. They would thus
    become much more analogous to toxins that cause diseases
    such as mesothelioma which I discuss in more detail below.
    However, we do not know the extent to which
    byproducts of uranium production have an exceedingly short
    half-life or whether they have exceptionally low energies. If
    they have a momentary short half-life or exceptionally low
    energies, their presence at the stacks and vents would be
    irrelevant to determining levels at the roof boundary. This is
    because they would have disintegrated into sub particles
    before reaching the roof boundary and would likely not have
    had enough energy to cause any damage even if they reached
    the roof’s perimeter and beyond into the community.
    Plaintiffs did not offer any evidence that would allow a fact
    finder to conclude that the levels at vents and stacks persisted
    at the roof boundary. Accordingly, evidence of the levels at
    the stacks and vents cannot satisfy their burden of
    establishing a breach at the relevant point—the roof
    boundary.
    I also have reservations about the Majority’s
    conclusion that 
    10 C.F.R. § 20.106
    (a) requires averaging as
    opposed to merely allowing Plaintiffs to average exposure
    over a year.9 However, here again, Plaintiffs’ proof is
    deficient because they did not attempt to introduce any
    evidence about the actual content of the uranium effluent that
    was discharged. If that effluent contained substances that
    8
    See id. at 632.
    9
    See Maj. Op. at 41-43.
    3
    were particularly toxic (such as plutonium), exposure to a
    given amount for a few days (perhaps even for a matter of
    hours) could cause cancer even though the exposure would
    appear minimal when averaged out over a year.10 There is an
    even more fundamental problem with Plaintiffs’ case that
    prevents them from surviving summary judgment, and that is
    why I feel compelled to write separately.
    In order for Plaintiffs to succeed, they must do more
    than show a breach of a duty resulting in exposure to excess
    radiation. They must show that the breach resulted in an
    exposure that proximately caused their injuries. It is here that
    Plaintiffs’ claims fail regardless of the quality of all of their
    other proof. Thus, even assuming a genuine issue of fact as
    to the exposure levels and Defendants’ breach, the evidence is
    still not sufficient to defeat summary judgment under the
    Price-Anderson Act because causation is lacking.
    II. CAUSATION
    A.        The Problems of Radiation Toxicity
    The Majority thoroughly and correctly explains
    causation as it applies to “toxic torts” under Pennsylvania
    law. However, the legal principle of causation has evolved
    from suits arising from exposure to manmade toxic
    substances such as asbestos.           As the Majority notes,
    mesothelioma is caused by exposure to asbestos, and it is
    therefore a “signature” disease. The disease almost never
    occurs absent exposure to asbestos.11 The problems of proof
    in such cases are quite similar to problems of causation in
    cases involving polychlorinated biphenyls (PCBs)12 or
    10
    See George L. Voelz, Plutonium and Health: How Great is
    the Risk?, Los Alamos Sci. 83 (2000),
    https://fas.org/sgp/othergov/doe/lanl/pubs/00818013.pdf;
    Katherine Harmon, Health Risk Fears Escalate as Japan
    Nuclear Plant’s Radioactive Release Remains Uncertain, Sci.
    Am. (Mar. 18, 2011),
    https://www.scientificamerican.com/article/health-risk-
    fukushima/ (“Plutonium is of graver concern because of its
    exceptionally long half-life (about 24,000 years) and its
    propensity to cause lung cancer if inhaled.”).
    11
    Maj. Op. at 50-51.
    12
    See In re Paoli R.R. Yard PCB Litig., 
    35 F.3d 717
     (3d Cir.
    1994).
    4
    4
    pneumoconiosis (black lung disease),13 to name but a few of
    the pathological byproducts of modernization. In such cases,
    a pathology is caused by contact (usually ingestion) with a
    foreign substance that the injured person would not have
    otherwise been exposed to, or would have been exposed to
    only in relatively insignificant quantities, and that pathology
    almost never occurs in the absence of exposure to that toxic
    substance. Accordingly, causation can be established by
    showing that defendant made (or controlled) a substance,
    plaintiff has a disease that almost never occurs absent contact
    with defendant’s substance, and plaintiff had sufficient
    contact with defendant’s product (i.e. “frequency, regularity,
    and proximity of exposure”) to allow a fact finder to conclude
    that the defendant’s product was a substantial factor in the
    plaintiff’s death or injury.14 Radiation is different.
    In TMI II, we discussed the “scientific principles
    regarding the relationship between radiation and cancer.” 15
    As the Majority explains, “[m]anmade ionizing radiation can
    damage human cells.”16 An ion is nothing more than an
    electron that has been displaced from its orbit.17 Unlike with
    13
    See Mancia v. Dir., Office of Workers’ Comp. Programs,
    U.S. Dep’t of Labor, 
    130 F.3d 579
     (3d Cir. 1997).
    14
    See Rost v. Ford Motor Co., 
    151 A.3d 1032
     (Pa. 2016).
    15
    Maj. Op. at 13-15; see TMI II, 
    193 F.3d 613
    .
    16
    Maj. Op. at 13 (citing TMI II, 
    193 F.3d at 639-40
    ).
    Although we used the term “manmade” in TMI II, it is
    actually a misnomer that obscures some of the very important
    distinctions between environmental radiation naturally
    occurring and radiation from substances that are, in fact,
    manmade. The latter radiation is not actually “manmade.” It
    consists of natural elementary particles that are transformed
    by human activity. The resulting radiation is nevertheless the
    result of quantum mechanical processes. However, for the
    sake of convenience, we will also refer to this radiation as
    “manmade” as we did in TMI II.
    17
    TMI II, 
    193 F.3d at 639
     (“[A]n atom is ionized when an
    electron is ejected from its orbit and expelled from the
    atom.”). It is actually a sweeping generalization to refer to all
    ionizing radiation as resulting from a single displaced
    electron. A very detailed description of the process of
    5
    PCBs, asbestos or tobacco byproducts, we are constantly
    exposed to radiation on a daily basis. We are exposed from
    numerous natural sources including the sun,18 or naturally
    occurring radioactive elements such as radon in the ground
    surrounding our homes.19
    It is now beyond dispute that radiation can cause
    various types of cancer. However, unlike with asbestos and
    diseases, such as mesothelioma, radiation wreaks havoc with
    our bodies, not because it is a foreign substance (it is not), but
    because it transfers extra energy to our cells. This energy
    can, in turn, damage our DNA in numerous ways that are
    described in detail in TMI II.20
    Asbestos fibers cause mesothelioma by damaging the
    “mesothelial cells that control cell reproduction. Some
    damaged cells die and tumor suppressor genes stop others
    ionization (including the all important Columb Force) can be
    found at TMI II, 
    193 F.3d at 632-38
    .
    However, the complex distinctions are not important for
    purposes of this discussion. Therefore, rather than attempt
    more precision by distinguishing between the different types
    of ionizing particles and ionizing energy as we did in TMI II,
    we will refer to all ions as if they only consisted of electrons
    without attempting to distinguish between alpha, beta or
    gamma radiation or between orbital electrons and electrons
    created through nuclear reactions. The important thing for
    purposes of this discussion is that “[w]hen a charged particle
    passes through matter, it excites and ionizes atoms in its
    path.” 
    Id. at 635
    . This is what happens to human tissue that
    is exposed to radiation.
    18
    
    Id. at 644-47
    .
    19
    See Natural background radiation, Am. Cancer Soc’y,
    https://www.cancer.org/cancer/cancer-causes/radiation-
    exposure/x-rays-gamma-rays/natural-background-
    radiation.html (last revised Feb. 24, 2015) (explaining that
    radon is but one source of the background radiation that we
    are potentially exposed to on a daily basis and is listed only
    for purposes of illustration).
    20
    See TMI II, 
    193 F.3d at 640
    .
    6
    6
    from reproducing.”21 However, “[w]here suppressor genes do
    not stop the reproduction process, . . . the damaged cells
    divide, replicating the damage in the sister cells.”22 Over
    decades of continued growth of these cells, tumors develop.
    “This explains why mesothelioma has an extremely long
    latency period, as mesothelial cells have a very slow growth
    rate.”23 As expert testimony in a recent case from the
    Supreme Court of Pennsylvania established, “it is not
    scientifically possible to identify the particular exposure or
    exposures that caused a patient’s mesothelioma[.] . . .
    [I]nstead, the causative agent is ‘the series of exposures.’”24
    However, even though it is not possible to identify a
    particular exposure as causing a given occurrence of the
    disease, there is now no dispute that asbestos is responsible
    for mesothelioma.
    Although the disease process described above for
    mesothelioma is quite similar to that which is triggered by
    radiation after the cell is irradiated, there is a key difference
    that is very relevant to our discussion. As noted above, we do
    not normally develop diseases such as mesothelioma in the
    absence of exposure to the manmade carcinogens that can
    cause it. Thus, if a plaintiff can produce evidence of
    sufficient frequency, regularity, and proximity of exposure to
    asbestos to establish that it is more likely than not that that
    exposure was a substantial cause of subsequent disease, the
    plaintiff then need only prove that defendant manufactured or
    controlled the substance that plaintiff had been exposed to in
    order to recover. The same is true with any other “signature”
    disease.
    Unlike products such as asbestos and PCBs, radiation
    is not a foreign substance. All of us are exposed to it every
    second of every day both inside of buildings and outdoors.
    Yet, radiation can “damage structures within the human body
    as cells are disrupted or killed by the ionizing radiation
    [energy] itself, and as energy is transferred to cells triggering
    21
    Rost, 151 A.3d at 1039 (citations omitted).
    22
    Id.
    23
    Id.
    24
    Id.
    7
    second-order chemical changes.”25 “Unlike a chemical
    product, which may be traceable to a particular manufacturer,
    different sources of radiation are not distinguishable, nor is
    there any noticeable difference between cancers caused by
    nuclear-power production and those caused by other sources
    of radiation.”26
    [M]edical evaluation, by itself, can neither
    prove nor disprove that a specific malignancy
    was caused by a specific radiation exposure [or
    series of exposures]. Therefore, the primary
    basis to link specific cancers with specific
    radiation exposures is data that has been
    collected regarding the increased frequency of
    malignancies following exposure to ionizing
    radiation. In other words, causation can only be
    established (if at all) from epidemiological
    studies of populations exposed to ionizing
    radiation.27
    However, epidemiological studies of exposed
    populations can only establish the percentage by which the
    incidence of given cancers in that population exceeds the rate
    for those same cancers in similar populations not exposed to
    the source of radiation. No study can determine whether the
    cancer of a given member of that population was the result of
    exposure to a defendant’s product or to radiation released
    from a defendant’s facility. As we explained in TMI II, “the
    task of establishing causation is greatly complicated by the
    reality that a given percentage of a defined population will
    contract cancer even absent any exposure to ionizing
    25
    William D. O’Connell, Causation’s Nuclear Future:
    Applying Proportional Liability to the Price-Anderson Act, 
    64 Duke L.J. 333
    , 348 (2014) [hereinafter O’Connell] (citing
    James E. Turner, Atoms, Radiation, and Radiation Protection
    421 (3d ed. 2007) [hereinafter Turner], available at
    http://nuclear.dababneh.com/Radiation-Undergrad-
    2/Atoms,%20Radiation,%20and%20Radiation%20Protection.
    pdf.
    26
    
    Id.
     at 350 (citing Turner at 468).
    27
    TMI II, 
    193 F.3d at 643
     (citations omitted).
    8
    8
    radiation.”28 This probability conundrum is even more of an
    issue when we try to compare members of a population who
    have only been exposed to natural radiation with members of
    the same population who have been exposed to that radiation
    plus radiation emanating from a defendant’s product or
    facility.
    Plaintiffs who must prove that exposure to a particular
    source of radiation was a substantial cause of their injuries
    therefore face an insurmountable task that the law has yet to
    satisfactorily address. The task is further complicated by the
    fact that radiation includes different kinds of particles (i.e.
    alpha, gamma, beta), each with different properties including
    different levels of energy and thus having a different
    capability of damaging human cells.29 As the NRC has
    explained:
    [N]atural radiation . . . is always present in the
    environment. It includes cosmic radiation which
    comes from the sun and stars, terrestrial
    radiation which comes from the Earth,
    and internal radiation which exists in all living
    things. The typical average individual exposure
    in the United States from natural background
    sources is about 300 millirems per year.30
    Yet, although there is general scientific agreement that
    radiation can cause cancer, we are still at the rudimentary
    stages of understanding the etiology of cancers. 31
    As if this does not make plaintiffs’ task in such cases
    difficult enough, two additional considerations further
    complicate inquiries into causation. First, as has already been
    mentioned, not all radiation has the same energy level. Some
    radiation can be filtered out by barriers no more substantial
    28
    
    Id. at 643-44
    . For a detailed explanation of the two major
    sources of natural radiation and average doses, see 
    id.
     at 644-
    48.
    29
    For a detailed discussion of this, see 
    id.
    30
    U.S. Nuclear Regulatory Comm’n, Background radiation,
    https://www.nrc.gov/reading-rm/basic-
    ref/glossary/background-radiation.html.
    31
    See TMI II, 
    193 F.3d at 644-48
    .
    9
    than sunscreen, or surface tissue, yet some radiation is
    capable of penetrating lead.32 Thus, mere proximity to a
    source of radiation does not necessarily establish a sufficient
    “absorbed dose” to link an individual’s illness to that
    proximity.33 This point is illustrated in the extreme by the
    fact that “[c]rews of nuclear submarines have possibly the
    lowest radiation exposure of anyone, despite living within a
    few meters of a nuclear reactor, since they are exposed to less
    natural background radiation than the rest of us [(the ocean
    shelters them)], and the reactor compartment is well
    shielded.”34
    Second, the difficulty of linking a potentially
    radiation-related pathology to a defendant instead of to
    background radiation is made exponentially more difficult by
    the fact that some people have a genetic predisposition to
    diseases associated with radiation exposure, while others have
    a genetic composition that seems to protect them from the
    otherwise harmful effects of radiation. Indeed, more than one
    physician has counseled that the best way to guard against
    contracting cancer is to “choose your parents carefully.”35
    Genetic research has even led researchers to conclude that:
    [P]erhaps a fortunate genetic endowment
    protects some lifelong smokers from lung
    cancer, while a genetic mischance induces lung
    cancer in some non-smokers.                 Both
    environmental and genetic differences between
    individuals appear responsible for at least some
    32
    See 
    id.
     at 637 n.36.
    33
    
    Id. at 637
     (“The absorbed energy per unit mass of material
    is termed the ‘absorbed dose.’”).
    34
    World Nuclear Ass’n, Nuclear Radiation and Health
    Effects, http://www.world-nuclear.org/information-
    library/safety-and-security/radiation-and-health/nuclear-
    radiation-and-health-effects.aspx.
    35
    See, e.g., Huber R. Warner, If You Wish to Live a Long
    Time in Good Health, Choose Your Parents Carefully, 62A J.
    of Gerontology: Biological Scis. 575 (2007), available at
    https://www.ncbi.nlm.nih.gov/pubmed/17595411; see also
    Steve C. Gold, When Certainty Dissolves into Probability: A
    Legal Vision of Toxic Causation for the Post-Genomic Era,
    
    70 Wash. & Lee L. Rev. 237
    , 259 (2013) [hereinafter Gold].
    10
    10
    of the variation in individuals’ responses to
    toxic exposures. For the most part, it has been
    impossible (or at least impractical) to identify,
    quantify, and tease apart these possibilities
    using the investigatory tools of toxicology,
    environmental epidemiology, conventional
    biochemistry, and classical genetics.36
    Yet, Plaintiffs such as those here, must produce evidence that
    will establish that their injuries are more likely than not
    caused by effluents from Defendants’ uranium plant. I
    simply do not see any way they can do that given the current
    state of the law.
    B. Congress’s Response to Causation Issues
    Congress has recognized the problems inherent in
    attempting to prove causation in Public Liability Actions
    almost from the very beginning of our attempts to harness the
    power of the atom. The Atomic Energy Act of 1946 created
    the Joint Committee on Atomic Energy to correct the
    deficiencies of the Price-Anderson Act, including the
    stringent burden of establishing causation.37 The Committee
    36
    Gold at 258-59.
    37
    Taylor Meehan, Lessons from the Price-Anderson Nuclear
    Industry Indemnity Act for Future Clean Energy
    Compensatory Models, 
    18 Conn. Ins. L.J. 339
    , 346 (2012)
    [hereinafter Meehan]; see also Michael Flynn, A Debt Long
    Overdue, Bulletin of the Atomic Scientists 41-42 (2001) (The
    Energy Employees Occupational Illness Compensation Act
    acknowledged that “nuclear weapons workers were put at risk
    building the country’s arsenal.” Acknowledging the
    difficulties associated with establishing causation, and
    “[b]ecause the government failed to adequately track
    exposures at these sites, [the Act] assumes that workers’
    cancers are work related, thus relieving the workers of the
    near-impossible task of having to prove the connection.”
    Further, the Act “establishes the possibility that other sites
    and illnesses may be added to the cohort at a later date.”); see
    also David Rocchio, The Price-Anderson Act: Allocation of
    the Extraordinary Risk of Nuclear Generated Electricity: A
    Model Punitive Damage Provision, 14 B.C. Envtl. Aff. L.
    11
    was also concerned with state statutes of limitation that could
    nullify meritorious claims because of the latency of injuries
    caused by radiation.38 Consequently, the 1966 amendments
    to the Act included a provision for the waiver of various
    defenses under state tort law in the event of an “extraordinary
    nuclear occurrence.”39 An “extraordinary nuclear occurrence”
    was defined as:
    [A]ny event causing a discharge or dispersal of .
    . . byproduct material from its intended place of
    confinement in amounts offsite, . . . which the
    Nuclear Regulatory Commission or the
    Secretary of Energy. . . determines to be
    substantial, and which the Nuclear Regulatory
    Commission or the Secretary of Energy. . .
    determines has resulted or will probably result
    in substantial damages to persons offsite . . ..40
    “This provision was enacted in order to assure that the
    victim’s entitlement to compensation would be determined
    under a strict liability standard, instead of the negligence
    standard that most state courts require.”41 The amendments
    also included a provision that waived state statutes of
    limitation that were more limited than the three-year limit
    established under the Price-Anderson Act.42 However, the
    overarching problem of causation was not impacted by
    attempts to augment statutes of limitation or impose strict
    Rev. 521, 538-39 (1987) [hereinafter Rocchio] (citing
    Hearings Before the Joint Committee on Atomic Energy on
    Proposed Amendments to the Price-Anderson Act Relating to
    Waiver of Defenses, 89th Cong., 2d Sess. 105-07 (1966),
    available at
    https://www.loc.gov/resource/conghear08.00170174379/?sp=
    10).
    38
    Rocchio at 539.
    39
    
    42 U.S.C. § 2014
    (j).
    40
    
    Id.
    41
    Meehan at 347.
    42
    Id.; see 
    42 U.S.C. § 2210
    (n)(1)(F)(iii) (The Act allows “any
    issue or defense based on any statute of limitations if suit is
    instituted within three years from the date on which the
    claimant first knew, or reasonably could have known, of his
    injury or damage and the cause thereof.”).
    12
    12
    liability. In either case, a plaintiff would still have to
    establish that a given pathology was caused by exposure to a
    defendant’s radiation rather than background radiation,
    heredity or some other factor. Accordingly, this legislative
    effort was only helpful in the exceedingly rare cases where
    that evidentiary gap could be bridged.
    In 1988, Congress created the Presidential
    Commission on Catastrophic Nuclear Accidents to “conduct a
    comprehensive study of appropriate means of fully
    compensating victims of a catastrophic nuclear accident that
    exceeds the aggregate public liability . . . in the statute . . . .”43
    In its final report to Congress, the Commission “sought to
    identify the ‘next best’ approach, since attaining the ‘best’
    solution, compensating only those whose cancers or other
    latent illnesses were caused by the accident, is not currently
    possible.”44 The options included:
    Option A, relaxing traditional
    notions of proof of causation and
    paying something to everyone
    who gets cancer; Option B,
    retaining and rigorously applying
    traditional standards, which would
    result in paying few, if any,
    claims; and Option C, adopting
    some proxy for direct proof of
    causation, such as imputing group
    risk to individuals who actually
    develop cancer and paying those
    claims where the association
    between radiation exposure and a
    particular cancer is the strongest
    (or at least at some minimum
    level), with the option, where a
    strong association is required for a
    “full” award, of also paying lesser
    43
    Presidential Comm’n on Catastrophic Nuclear Accidents,
    Report to the Congress from the Presidential Commission on
    Catastrophic Nuclear Accidents, Letter to the Senate (August
    1990) [hereinafter Report], available at
    http://www.state.nv.us/nucwaste/news/rpccna/pcrcna02.htm.
    44
    
    Id.
     at ch. 4.IV.B.
    13
    amounts on those claims with a
    somewhat weaker association.45
    The Commission ultimately recommended Option C46 and
    provided three possible ways to implement that Option, while
    noting that better techniques can be developed in the future: 47
    The first would pay the full
    amount for any diagnosed cancer
    where the probability of causation
    (PC) is .5 or greater, and a
    declining amount down to a cutoff
    of PC = .2, at which compensation
    would be 20 percent of the full
    award, determined in accordance
    with Chapter 3.
    The second variation would pay
    the full amount for any diagnosed
    cancer where the PC is .5 or
    greater, and a declining amount
    down to a PC of .2, at which
    compensation would be 30
    percent of a full award.
    The third variation, which is most
    like Option A, above, would
    simply pay a benefit to anyone in
    the affected area with a diagnosed
    cancer whose radiation exposure
    indicated a PC of 20 percent or
    greater. Congress might elect to
    make this a full award determined
    in accordance with Chapter 3, or a
    fixed     dollar    amount,     or
    reimbursement for actual medical
    expenses.48
    45
    
    Id.
    46
    This option is known as the “probability of causation” rule.
    47
    Report at ch. 4.II.
    48
    
    Id.
     at ch. 4.IV.B. (citation omitted).
    14
    14
    Courts have adopted variations of these and other options as
    discussed below. However, despite these efforts, the problem
    of establishing causation in these suits remains because we
    continue to approach such claims the same way we approach
    injuries resulting from asbestos, defective brakes, holes in
    pavement, and falls in the aisles of the neighborhood
    supermarket.
    C. Evolving Case Law: Relaxing Standards
    Some courts have responded by implementing a more
    relaxed analytical framework for these suits. None of these
    approaches has yet won general acceptance, and each
    contains certain flaws.49
    1. The Preponderance Rule
    The preponderance rule is very similar to the typical
    preponderance of the evidence burden. It requires a plaintiff
    to prove that the defendant’s activity was more likely than not
    either the but-for causation or a substantial factor in causing
    the plaintiff’s injuries.50 Courts have equated the “more
    49
    The following discussion of evolving law is not intended as
    an exhaustive survey. Rather, I mention it only to offer
    additional examples of the problem and some solutions that
    have been suggested.
    50
    Shelly Brinker, Opening the Door to the Indeterminate
    Plaintiff: An Analysis of the Causation Barriers Facing
    Environmental Toxic Tort Plaintiffs, 
    46 UCLA L. Rev. 1289
    ,
    1303-04 (1999) [hereinafter Brinker]; see Sterling v. Velsicol
    Chemical Corp., 
    855 F.2d 1188
    , 1201 (6th Cir. 1988)
    (“Whereas numerous jurisdictions have rejected medical
    experts’ conclusions based upon a ‘probability,’ a
    ‘likelihood,’ and an opinion that something is ‘more likely
    than not’ as insufficient medical proof, the Tennessee courts
    have adopted a far less stringent standard of proof and have
    required only that the plaintiffs prove a causal connection
    between their injuries and the defendant’s tortious conduct by
    a preponderance of the evidence. While, in accordance with
    Tennessee common law, plaintiffs’ proof by a reasonable
    medical certainty requires them only to establish that their
    particular injuries more likely than not were caused by
    15
    likely than not” element of this rule to a level of certainty
    greater than 50%.51 The preponderance rule does not reduce a
    plaintiff’s burden of showing cause-in-fact, it allows the
    plaintiff to present individualized and statistical evidence to
    establish that the defendant’s activities were likely a
    substantial contributor to plaintiff’s injury.52
    Because of the 50% threshold requirement, plaintiffs
    who cannot demonstrate a greater than 50% likelihood that
    the defendant caused their injuries do not recover anything.
    However, if plaintiffs are able to show, for example, that
    defendant is responsible for causing injuries to 51% of the
    exposed population, every plaintiff recovers even though the
    evidence only proved that 51% of the individuals in the
    exposed population suffered injuries because of defendant’s
    activities.
    This is basically the way causation is now determined
    in Pennsylvania, as explained in the Majority’s discussion of
    Rost v. Ford Motor Co.,53 except that it allows group recovery
    if any group member of the group is successful in showing
    his/her disease was proximately caused (i.e. by a 51%
    probability) by a defendant.
    There are several obvious problems with this
    approach. As we have explained above, because everyone in
    ingesting the contaminated water, their proofs may be neither
    speculative nor conjectural.”).
    51
    In re Agent Orange Prod. Liab. Litig., 
    597 F. Supp. 740
    ,
    835-37 (E.D.N.Y. 1984), aff’d sub nom. In re Agent Orange
    Prod. Liab. Litig. MDL No. 381, 
    818 F.2d 145
     (2d Cir. 1987)
    (quoting Jackson v. Johns-Manville Sales Corp., 
    727 F.2d 506
    , 516 (5th Cir. 1984), on reh'g, 
    750 F.2d 1314
     (5th Cir.
    1985)) (The rule provides an “‘all or nothing’ approach,
    whereby [assuming all other elements of the cause of action
    are proven], the plaintiff becomes entitled to full
    compensation for those . . . damages that are proved to be
    ‘probable’ (a greater than 50 percent chance), but is not
    entitled to any compensation if the proof does not establish a
    greater than 50 percent chance.”).
    52
    Id. at 835.
    53
    See Maj. Op. at 49-52 (citing Rost, 
    151 A.3d 1032
    ).
    16
    16
    the population will have been exposed to radiation during
    their lifetime, and since it is not yet possible to isolate the
    effect of radiation from a particular source, the same
    problems of causation remain.           This approach merely
    suspends proof of causation for everyone else if anyone in the
    group can prove causation. All recover based on the showing
    that someone should recover. However the nearly impossible
    burden of proving causation remains.          Moreover, if the
    burden can somehow be satisfied by any one plaintiff or a
    subset of plaintiffs, the result imposes “crushing liability” on
    defendants that could negatively impact some efforts to find
    alternative energy sources.54 In addition, this approach
    allows plaintiffs whose injury is probably genetic or due to
    background radiation to recover along with those who can
    trace their injury to the disputed source. But, the fact that one
    or more plaintiffs in a given population have been injured by
    exposure to a given source certainly does not mean that
    everyone in that population has been. Yet, everyone would
    ride along on the claims of those who can show a defendant
    proximately caused his/her injury.
    2. The Proportionality Rule
    Alternatively, some courts have used the
    proportionality rule. This rule presumes causation when a
    plaintiff presents statistical evidence showing that it is likely
    that a defendant’s activities caused an injury to a proportion
    of the individuals in the exposed population.55 This approach
    may, at first, also appear to resemble Pennsylvania’s
    “frequency, regularity and proximity” test. However, under a
    pure implementation of this proportionality rule, plaintiffs are
    not required to present individualized proof. For example, if
    100 plaintiffs alleged that defendant’s disposal of hazardous
    wastes caused their injury and the risk of developing such
    injury in the exposed population is 55%, then every plaintiff
    will recover 55%.56 However, plaintiffs will likely never
    54
    Brinker at 1309-10.
    55
    Id. at 1313.
    56
    Sindell v. Abbott Labs., 
    607 P.2d 924
    , 937 (Cal. 1980); see
    Cottle v. Superior Court, 
    5 Cal. Rptr. 2d 882
    , 905 (Ct. App.
    1992) (Johnson, J., dissenting) (“Instead of choosing between
    the extremes of overcompensation and no compensation at all
    17
    obtain complete recovery under such a tort regime.57 In
    addition, this rule still allows plaintiffs whose injuries or
    deaths were likely attributable primarily to background
    radiation or genetics (or a combination of the two) to recover.
    3. The Allen Rule
    The United States District Court for the District of Utah
    presented another option in Allen v. United States, which
    involved a dispute arising from atmospheric testing. That
    court resorted to burden shifting. A rebuttable presumption of
    liability arises if a plaintiff can show a correlation between
    his or her injuries and the increased risk resulting from a
    defendant’s negligent release of radiation. The problem here
    is that correlation is not the same as causation.58 Yet, using
    this approach, Allen held that
    [w]here a defendant who negligently creates a
    radiological hazard which puts an identifiable
    population group at increased risk, and a
    member of that group at risk develops a
    biological condition which is consistent with
    having been caused by the hazard to which he
    has been negligently subjected, such
    consistency having been demonstrated by
    this solution allows plaintiffs to recover a percentage of their
    damages from those responsible for their exposure to the
    toxic. Under this formula defendants responsible for the toxic
    exposure are liable to all those who were exposed and later
    suffered injury—including those who may have suffered the
    injury even if they had never come near the toxic
    substance. But defendants are only liable for a percentage of
    plaintiffs’ damages equal to the degree this exposure
    increased plaintiffs’ risk of injury. For example, assume a
    chemical increases the risk of cancer by 15 percent among
    those exposed to the toxin. All exposed to this chemical who
    later came down with cancer would be entitled to recover 15
    percent of their total damages from those responsible for the
    exposure.”).
    57
    Brinker at 1318 (citation omitted).
    58
    For example, the height of males and females correlates to
    whether they play professional basketball. However, playing
    professional basketball does not cause players to grow taller.
    18
    18
    substantial, appropriate, persuasive and
    connecting factors, a fact finder may reasonably
    conclude that the hazard caused the condition
    absent persuasive proof to the contrary offered
    by the defendant.59
    In undertaking this inquiry, the fact finder considers
    the following non-exhaustive list of factors:
    (1) the probability that plaintiff was exposed to
    ionizing radiation due to nuclear fallout from
    atmospheric testing at the . . . Test Site at rates
    in excess of natural background radiation; (2)
    that plaintiff's injury is of a type consistent with
    those known to be caused by exposure to
    radiation; and (3) that plaintiff resided in
    geographical proximity to the . . . Test Site . . . .
    Other factual connections may include but are
    not limited to such things as time and extent of
    exposure to fallout, radiation sensitivity factors
    such as age or special sensitivities of the
    afflicted organ or tissue, retroactive internal or
    external dose estimation by current researchers,
    a latency period consistent with a radiation
    etiology, or an observed statistical incidence of
    the alleged injury greater than the expected
    incidence in the same population.60
    59
    Allen v. United States, 
    588 F. Supp. 247
    , 415 (D. Utah
    1984), rev’d on other grounds, 
    816 F.2d 1417
     (10th Cir.
    1987).
    60
    Id.; see also Restatement (Second) of Torts § 433 (1965)
    (“The following considerations are in themselves or in
    combination with one another important in determining
    whether the [defendant’s] conduct is a substantial factor in
    bringing about harm to another: (a) the number of other
    factors which contribute in producing the harm and the extent
    of the effect which they have in producing it; (b) whether the
    actor’s conduct has created a force or series of forces which
    are in continuous and active operation up to the time of the
    harm, or has created a situation harmless unless acted upon by
    other forces for which the actor is not responsible; (c) lapse of
    time.”); see also O’Connell (proposing a species of
    proportionality tests that allows compensation based upon
    19
    The problem here is that because this rule presents several
    factors that courts can consider, consistency may be elusive
    and courts addressing substantially identical circumstances
    may reach different results. Nevertheless, this approach
    appears to be the most promising and the most consistent with
    the realities of the risk created by an activity that can expose a
    population to radiation. It may be that the only realistic
    approach is to compensate an identified population for the
    increased risk occasioned by a given activity. I do not,
    however, suggest that such nagging questions as the amount
    of that compensation, identifying the population that is at
    increased risk, or countless other factors lend themselves to
    easy or equitable resolution.
    None of these approaches have yet gained wide
    acceptance and, as should be evident from this discussion,
    none of these approaches is close to perfect. Rather, they are
    sorely needed attempts to adopt (or augment) the traditional
    rules requiring a direct and linear cause-in-fact relationship
    with no intervening causes, to the reality of exposure to
    ionizing radiation resulting from human activities.
    III. CONCLUSION
    For reasons I have explained, my concerns about some
    of the District Court’s rulings are not sufficient to cause me to
    conclude that the court erred in granting summary judgment
    against these Plaintiffs and dismissing the complaint.
    Problems with the Plaintiffs’ proof (and lack thereof) and the
    Herculean task of trying to produce enough evidence to get to
    a fact finder on the issue of causation are simply too
    formidable for these claims to survive.
    As I have explained, this will almost always be the
    case until state supreme courts, state legislatures and/or
    Congress devise a way to more fairly address the very real
    and substantial dangers posed by activities that increase the
    risk of exposing communities to ionizing radiation. However,
    increased risk once that risk exceeds a certain threshold. The
    threshold is, of course, a policy matter and can be determined
    by legislatures after hearings on this issue.).
    20
    20
    since that day is not yet here, I agree that Defendants were
    entitled to summary judgment. I can only hope that the dues
    that we pay for the comforts of living in the atomic age will
    one day not require us to forego remedies for the harmful
    effects of the nuclear byproducts of that modernization, which
    we are still trying to understand.
    21
    

Document Info

Docket Number: 15-3506, 15-3507, 15-3508, 15-3509, 15-3510, 15-3511, 15-3512, 15-3513, 15-3514, 15-3515, 15-3564, 15-3639, 15-3640, 15-3641, 15-3642, 15-3643, 15-3644, 15-3645, 15-3646, 15-3647, 15-3648, 15-3649, 15-3650, 15-3651, 15-3652, 15-3653, 15-3654, 15-3655, 15-3

Judges: Smith, McKee, Restrepo

Filed Date: 8/23/2017

Precedential Status: Precedential

Modified Date: 11/5/2024

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