Montrose Chemical Corp. v. Super. Ct. ( 2017 )


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  • Filed 9/8/17 (unmodified opinion attached)
    CERTIFIED FOR PUBLICATION
    IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA
    SECOND APPELLATE DISTRICT
    DIVISION THREE
    MONTROSE CHEMICAL                              B272387
    CORPORATION OF CALIFORNIA,
    (Los Angeles County
    Petitioner,                             Super. Ct. No. BC005158)
    v.                                      ORDER MODIFYING OPINION
    [NO CHANGE IN JUDGMENT]
    SUPERIOR COURT OF THE STATE
    OF CALIFORNIA, COUNTY OF LOS
    ANGELES,
    Respondent;
    CANADIAN UNIVERSAL
    INSURANCE COMPANY, INC., ET
    AL.,
    Real Parties in Interest.
    THE COURT:
    It is ordered that the opinion filed herein on August 31,
    2017, be modified as follows:
    On page 3 of the opinion, insert the name Deborah Lynn
    Stein in counsel listing for Real Parties in Interest Travelers
    Casualty and Surety Company and The Travelers Indemnity
    Company so that the opinion reads: Simpson Thacher & Bartlett,
    Peter R. Jordon, Andrew T. Frankel, and Deborah Lynn Stein for
    Real Parties in Interest Travelers Casualty and Surety Company
    and The Travelers Indemnity Company.
    _______________________________________________________
    EDMON, P. J.          ALDRICH, J.*          LAVIN, J.
    *      Retired Associate Justice of the Court of Appeal, Second
    Appellate District, assigned by the Chief Justice pursuant to
    article VI, section 6 of the California Constitution.
    2
    Filed 8/31/17 (unmodified version)
    CERTIFIED FOR PUBLICATION
    IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA
    SECOND APPELLATE DISTRICT
    DIVISION THREE
    MONTROSE CHEMICAL                              B272387
    CORPORATION OF CALIFORNIA,
    (Los Angeles County
    Petitioner,                             Super. Ct. No. BC005158)
    v.
    SUPERIOR COURT OF THE STATE
    OF CALIFORNIA, COUNTY OF LOS
    ANGELES,
    Respondent;
    CANADIAN UNIVERSAL
    INSURANCE COMPANY, INC., ET
    AL.,
    Real Parties in Interest.
    Petition for writ of mandate from an order of the Superior
    Court of Los Angeles County, Elihu Berle, Judge. Granted in
    part and denied in part with directions.
    Latham & Watkins, Brook B. Roberts, John M. Wilson and
    Drew T. Gardiner for Petitioner.
    No appearance on behalf of Respondent.
    Sinnott Puebla Campagne & Curet, Kenneth H. Sumner
    and Lindsey A. Morgan for Real Party in Interest AIU Insurance
    Company.
    Sinnott, Puebla, Campagne & Curet and Randolph P.
    Sinnott; Cozen O’Conner and John Daly for Real Party in
    Interest Zurich International (Bermuda) Ltd.
    Duane Morris, Max H. Stern and Jessica E. La Londe for
    Real Party in Interest American Centennial Insurance Company.
    Craig & Winkelman and Bruce H. Winkelman for Real
    Parties in Interest American Re-Insurance Company.
    Selman & Breitman, Ilya A. Kosten and Kelsey C. Start for
    Real Parties in Interest Transport Insurance Company and
    Lamorak Insurance Company.
    Selman & Breitman and Elizabeth M. Brockman for Real
    Party in Interest Federal Insurance Company.
    Berkes, Crane, Robinson & Seal, Steven M. Crane and
    Barbara S. Hodous for Real Party in Interest Continental
    Casualty Company and Columbia Casualty Company.
    Lewis Brisbois Bisgaard & Smith, Peter L. Garchie and
    James P. McDonald for Real Party in Interest Employers Mutual
    Casualty Company.
    Barber Law Group and Bryan M. Barber for Real Party in
    Interest Employers Insurance of Wausau.
    McCurdy & Fuller, Kevin G. McCurdy and Vanci Y. Fuller
    for Real Parties in Interest Everest Reinsurance Company, et al.
    Chamberlin Keaster & Brockman, Kirk C. Chamberlin and
    Kevin J. Schettig for Real Parties in Interest Providence
    Washington Insurance Company, et al.
    Tressler, Linda Bondi Morrison and Ryan B. Luther for
    Real Parties in Interest Allstate Insurance Company.
    2
    Archer Norris, Charles R. Diaz and GailAnn Y. Stargardter
    for Real Parties in Interest Fireman’s Fund Insurance Company,
    et al.
    Lewis, Brisbois, Bisgaard & Smith, Jordon E. Harriman
    and Shannon L. Santos for Real Parties in Interest General
    Reinsurance Corporation, et al.
    Hinshaw & Culbertson, Thomas R. Beer and Peter J.
    Felsenfeld for Real Party in Interest Gerling Konzern Allgemeine
    Versicherungs-Aktiengesellschaft.
    O’Melveny & Myers, Richard B. Goetz, Zoheb P. Noorani
    and Michael Reynolds for Real Party in Interest TIG Insurance
    Company.
    McCloskey, Waring & Waisman and Andrew McCloskey for
    Real Parties in Interest Westport Insurance Corporation, et al.
    Simpson Thacher & Bartlett, Peter R. Jordon and Andrew
    T. Frankel for Real Parties in Interest Travelers Casualty and
    Surety Company and The Travelers Indemnity Company.
    Morgan Lewis & Bockius, Michel Y. Horton, Jeffrey S.
    Raskin and David S. Cox for ITT LLC and Santa Fe Braun, Inc.
    as Amicus Curiae on behalf of Petitioner.
    _________________________
    3
    Petitioner Montrose Chemical Corporation of California
    (Montrose) for many years manufactured the pesticide dichloro-
    diphenyl-trichlorethane (DDT). Real parties in interest are
    insurers that issued excess comprehensive general liability (CGL)
    policies to Montrose in relevant years. The present dispute
    concerns the sequence in which Montrose may access its excess
    CGL policies to cover its liability for environmental injuries
    caused by DDT.
    Through a motion for summary adjudication, Montrose
    sought a declaratory judgment that it may “electively stack”
    excess policies—i.e., that it may access any excess policy issued in
    any policy year so long as the lower-lying policies for the same
    policy year have been exhausted. All of the excess insurers
    opposed Montrose’s motion for summary adjudication; many of
    the excess insurers also sought through a cross-motion for
    summary adjudication a ruling that no insurer had a duty to pay
    a covered claim until Montrose had “horizontally exhausted” its
    lower-lying excess policies in all triggered policy years.
    The trial court rejected “elective stacking” in favor of
    “horizontal exhaustion,” ordering that higher-level excess policies
    could not be accessed until lower-level policies had been
    exhausted for all policy years. It thus denied Montrose’s motion
    for summary adjudication and granted the excess insurers’ cross-
    motion for summary adjudication. Montrose then filed the
    present petition for writ of mandate challenging the trial court’s
    summary adjudication order.
    We agree with the trial court that “elective stacking” is
    inconsistent with the policy language of at least some of the more
    than 115 excess policies at issue and is not compelled by
    California Supreme Court authority. We therefore conclude that
    4
    the trial court properly denied Montrose’s motion for summary
    adjudication. Our holding is not as expansive as the trial court’s,
    however. Specifically, we do not hold that policies must be
    horizontally exhausted at each coverage level and for each year
    before higher-level policies may be accessed. Instead, we
    conclude that the sequence in which policies may be accessed
    must be decided on a policy-by-policy basis, taking into account
    the relevant provisions of each policy. We therefore reverse in
    part the trial court’s grant of the insurers’ motion for summary
    adjudication.
    FACTUAL AND PROCEDURAL HISTORY
    I.
    Background
    From 1947 to 1982, Montrose manufactured DDT at a
    facility in Torrance, California. During the 1960’s,
    conservationists began to raise concerns about the effects of DDT
    on the environment, and in 1972 the federal government
    prohibited its use within the United States. Montrose continued
    to manufacture DDT for export at its Torrance facility until 1982.
    (Montrose Chemical Corp. v. Superior Court (1993) 
    6 Cal.4th 287
    ,
    292–293 (Montrose I).)
    In 1990, the United States and the State of California sued
    Montrose in the United States District Court for the Central
    District of California under the Comprehensive Environmental
    Response, Compensation, and Liability Act of 1980 (
    42 U.S.C. § 9607
     et seq.) (CERCLA). (United States, et al. v. Montrose
    Chemical Corporation of California, et al. (U.S. Dist. Ct.
    C.D.Cal.), 1990, No. CV 90–3122–AAH (JRx) (CERCLA action).)
    The CERCLA action alleged that Montrose’s operation of its
    Torrance facility caused environmental contamination that
    5
    damaged land, water, and wildlife in the Los Angeles Harbor and
    neighboring waters. (Montrose I, supra, 6 Cal.4th at pp. 292–
    293.)
    Montrose represents that it has entered into partial
    consent decrees in the CERCLA action through which it has
    incurred damages in excess of $100 million, and that additional
    future damages could approach or exceed that amount.
    II.
    The Present Coverage Litigation
    Montrose purchased “layers” of CGL policies from various
    insurance carriers to cover its operations at the Torrance facility
    from 1960 to 1986. In each of the relevant years, Montrose
    purchased a layer of “primary” CGL insurance policies that
    required the insurers to defend and indemnify Montrose for
    covered losses up to the policy limits. (Montrose I, supra,
    6 Cal.4th at pp. 292–293.) Above the “primary” insurance
    policies were multiple layers of “excess” CGL coverage, which
    provided additional coverage once underlying insurance was
    exhausted. In the early years, Montrose purchased just a few
    layers of excess coverage; in some later years, Montrose appears
    to have purchased more than 40 layers of excess coverage, with
    aggregate limits of liability in excess of $120 million. Montrose
    asserts that because the policies provide for different amounts of
    coverage in different years, the layers of excess coverage are not
    uniform. To provide just a single example, in some policy years
    the first layer excess policies provided coverage of up to
    $1 million; in other years, the first layer excess policies provided
    coverage of up to $2 million, $5 million, or $10 million.
    In August 1990, Montrose filed the present action,
    Montrose Chemical Corporation of California v. Canadian
    6
    Universal Insurance Co., Inc., et al., case No. BC005158, to
    resolve various coverage disputes with its primary insurers.
    Subsequently, Montrose amended its complaint to name its
    excess insurers as additional defendants.
    In 2006, the superior court stayed this action in response to
    Montrose’s concern that discovery in this case could prejudice its
    defense in the CERCLA action. The court lifted the stay in
    June 2014.
    In 2012, the California Supreme Court issued a decision in
    State of California v. Continental Ins. Co. (2012) 
    55 Cal.4th 186
     (Continental). As discussed more fully below, Continental
    held that where an ongoing environmental injury triggers
    multiple policies across many policy years, the insured may
    “stack” the policies “ ‘to form one giant “uber-policy” with a
    coverage limit equal to the sum of all purchased insurance
    policies.’ ” (Id. at pp. 200–201.)
    Following the Supreme Court’s decision in Continental,
    Montrose filed a Fifth Amended Complaint (complaint) in this
    action in September 2015. The complaint asserted a new 32nd
    cause of action for declaratory relief, seeking a declaration that:
    “a.    In order to seek indemnification under the Defendant
    Insurers’ excess policies, Montrose need only establish that its
    liabilities are sufficient to exhaust the underlying policy(ies) in
    the same policy period, and is not required to establish that all
    policies insuring Montrose in every policy period (including
    policies issued to cover different time periods both before and
    after the policy period insured by the targeted policy) with limits
    of liability less than the attachment point of the targeted policy,
    have been exhausted; and
    7
    “b.   Montrose may select the manner in which [to]
    allocate its liabilities across the policy(ies) covering such losses.”
    III.
    Cross-Motions for Summary Adjudication
    A.    Montrose’s Motion for Summary Adjudication
    Montrose moved for summary adjudication of the 32nd
    cause of action. Montrose asserted that a controversy had arisen
    between it and its excess insurers about the manner in which it
    could obtain indemnification under the excess policies. According
    to Montrose, the excess insurers had taken the position that
    Montrose could not access coverage under any excess policy until
    its liabilities exhausted all of the lower-lying excess coverage in
    every policy period. Montrose depicted the insurers’ approach as
    follows, assuming a hypothetical coverage portfolio and
    $100 million of liability resulting from continuous property
    damage over five years. In this example, Montrose must exhaust
    its first and second layer excess policies (each layer representing
    $10 million of coverage) in each policy year before accessing any
    of its third layer excess policies:
    Year 1       Year 2       Year 3     Year 4      Year 5
    $50 mil
    Layer 5
    $40 mil
    Layer 4
    $30 mil
    Layer 3
    $20 mil
    Layer 2
    $10 mil
    Layer 1
    8
    Montrose rejected the insurers’ horizontal exhaustion
    approach, asserting that it instead was entitled under the
    language of the excess policies and the Supreme Court’s holding
    in Continental to “electively stack” its coverage—i.e., to “select
    any policy to indemnify its liabilities, provided the policies
    immediately underlying that policy are exhausted” in the same
    policy period. Montrose provided the following example of how
    elective stacking might work, using the same hypothetical losses
    and coverage portfolio depicted above. In this example, Montrose
    accesses coverage from the first through third excess insurance
    layers for policy years two and three, and the first through fourth
    excess insurance layers for policy year four, without accessing
    any excess coverage for policy years one and five:
    Year 1      Year 2      Year 3      Year 4      Year 5
    $50 mil
    Layer 5
    $40 mil
    Layer 4
    $30 mil
    Layer 3
    $20 mil
    Layer 2
    $10 mil
    Layer 1
    9
    B.      Insurers’ Oppositions and Cross-Motion for Summary
    Adjudication
    A group of excess insurers (hereinafter, the Continental
    insurers)1 filed an opposition to Montrose’s motion for summary
    1     Those insurers are: Continental Casualty Company
    (Continental) and Columbia Casualty Company (Columbia),
    joined by AIU Insurance Company; Allstate Insurance Company
    (as successor-in-interest to Northbrook Excess and Surplus
    Insurance Company; American Centennial Insurance Company
    (American Centennial); American Home Insurance Company;
    Federal Insurance Company; Employers Insurance Company of
    Wausau; Everest Reinsurance Company (as successor-in-interest
    to Prudential Reinsurance Company); Fireman’s Fund Insurance
    Company; General Reinsurance Corporation; Granite State
    Insurance Company; Lamorak Insurance Company (formerly
    known as OneBeacon America Insurance Company), as
    successor-in-interest to Employers Commercial Union Insurance
    Company of America and The Employers Liability Assurance
    Corporation, Ltd.; Landmark Insurance Company; Lexington
    Insurance Company; Mt. McKinley Insurance Company (as
    successor-in-interest to Gibraltar Casualty Company); Munich
    Reinsurance America, Inc. (formerly known as American Re-
    Insurance Company); National Surety Corporation; National
    Union Fire Insurance Company of Pittsburgh, PA; New
    Hampshire Insurance Company; North Star Reinsurance
    Corporation; Providence Washington Insurance Company
    (successor by way of merger to Seaton Insurance Company,
    formerly known as Unigard Security Insurance Company,
    formerly known as Unigard Mutual Insurance Company);
    Transport Insurance Company (as successor-in-interest to
    Transport Indemnity Company); Westport Insurance
    Corporation, formerly known as Puritan Insurance Company,
    formerly known as Manhattan Fire and Marine Insurance
    Company); and Zurich International (Bermuda), Ltd.
    10
    adjudication, and separately filed their own cross-motion for
    summary adjudication. That motion sought summary
    adjudication on two grounds: (1) the 32nd cause of action (by
    which the Continental insurers sought a determination that
    Montrose was not entitled as a matter of law to electively stack
    its excess policies), and (2) the following “issue of duty”: “All
    underlying policy limits across the years of continuing property
    damage must be exhausted by payment of covered claims before
    any of the Insurers’ excess policies ha[s] a duty to pay covered
    claims.” The Continental insurers contended that well-
    established California law and the language of the relevant
    policies required Montrose to “exhaust coverage from all
    underlying insurers in each of the triggered policy periods, such
    that higher-level excess insurers’ obligations are triggered only
    when all primary and lower-level excess policies have been
    exhausted.” (Italics added.)
    Travelers Indemnity and Travelers Surety (formerly known
    as Aetna) (the Travelers insurers) opposed Montrose’s motion for
    summary adjudication, but did not separately move for summary
    adjudication. The Travelers insurers urged that California law
    did not apply to their policies, and that under the clear language
    of the policies, Montrose had to demonstrate that the underlying
    insurers “have paid or been held to pay the full amount of their
    respective limits of liability”—not merely that Montrose’s
    liabilities “are sufficient to exhaust the underlying policy(ies) in
    the same policy period.”2 According to the Travelers insurers,
    2      The Travelers insurers therefore urged that the declaration
    sought by Montrose “appears to leave open the possibility that
    Montrose can access Travelers’ higher-level excess policies
    (i) based solely on estimated liabilities that Montrose has not
    11
    Montrose’s assertion that its primary policies should be “deemed”
    exhausted was “misleading because the parties have not
    stipulated—and the Court has not found or ordered—that
    Montrose’s primary policies be ‘deem[ed]’ exhausted. Montrose,
    of course, will have the burden of proving that, in fact, its
    underlying insurance (including with respect to primary
    coverage) has been exhausted before it can seek coverage under
    its excess policies. That factual issue is not before the Court, and
    may not be decided in the guise of Montrose’s Motion currently
    before the Court.”
    IV.
    Order Denying Montrose’s Motion and
    Granting Continental Insurers’ Cross-
    Motion for Summary Adjudication
    The superior court denied Montrose’s motion and granted
    the Continental insurers’ cross-motion. The court began by
    describing the issues raised by the competing motions for
    summary adjudication:
    “[I]t’s the insurers’ contention that Montrose cannot access
    coverage under any of the excess policies until Montrose exhausts
    actually paid to date, (ii) based on liabilities allegedly incurred
    even if those liabilities were not actually paid by the underlying
    insurers (including settling insurers), or (iii) without showing
    that Montrose’s liabilities are actually covered under the terms of
    the underlying policies such that they might one day exhaust
    those underlying policies.” Indeed, the Travelers insurers
    asserted, “Montrose’s declaration would not even require
    Montrose to prove that its liabilities would be covered by
    underlying insurance, much less that they would ever actually
    exhaust that underlying insurance.” (Fn. omitted.)
    12
    all the underlying excess coverage in each policy period. This
    approach is generally referred to as a ‘horizontal exhaustion.’
    “In contrast, Montrose argues that it should instead be
    entitled to vertically stack all excess coverage triggered [in] each
    individual policy period, in effect allowing Montrose to select any
    available excess policy to indemnify its liabilities assuming that
    the policies immediately underlying that policy are exhausted for
    this specific policy in question. The approach is referred to as a
    ‘vertical exhaustion.’ ”
    The court then discussed the law generally applicable to
    primary and excess insurance:
    “Before coverage can attach under an excess policy, the
    policy limits of the underlying primary policy or policies must
    typically be exhausted. [Citation.] [¶] Normally, primary
    coverage is exhausted when a primary insurer pays its policy
    limits to settle a claim or to satisfy a judgment against the
    insurer. [Citation.]
    “Under California law, vertical exhaustion applies where
    an excess policy expressly provides coverage in excess of a specific
    primary policy for that same policy period. In such a scenario,
    excess coverage will attach after the specifically identified
    primary insurance has been exhausted, notwithstanding the
    existence of other underlying policies. [Citation.]
    “On the other hand, horizontal exhaustion applies in those
    situations where an excess policy provides coverage in excess to
    all underlying insurance, whether specifically scheduled or not.
    [Citation.] [¶] . . . [¶]
    “In cases such as the one before the court today in which
    the damages at issue occur continuously over a long period of
    13
    time, questions regarding policy exhaustion prove to be very
    complex. [¶] . . . [¶]
    “Consistent with the general rule[s] of insurance polic[y]
    interpretation, the first inquiry in continuous loss scenarios
    remains whether the excess policy imposes specific limits upon
    the coverage provider.
    “As the California Court of Appeal held in Community
    Redevelopment [Agency v. Aetna Casualty & Surety Co. (1996)
    
    50 Cal.App.4th 329
     (Community Redevelopment)], where an
    excess policy does not specifically describe . . . [¶] . . .and limit the
    underlying insurance policies [that must be exhausted], the
    horizontal exhaustion doctrine should apply.”
    The court then turned to the facts of the case before it:
    “In the present case, Montrose argues that pursuant to the
    California Supreme Court holding in [Continental], Montrose
    should be entitled to access its excess coverage under an elective
    stacking approach whereby a policyholder may select any
    triggered policy in its portfolio to indemnify its liabilities,
    provided that the policies underlying that policy are exhausted in
    accordance with their terms. [¶] . . . [¶]
    “Ultimately, Montrose fails to cite any binding authority
    which persuades this court that the court should not follow the
    well-established rule that horizontal exhaustion should apply in
    the absence of policy language specifically describing and limiting
    the underlying insurance.
    “Montrose additionally asserts that the language in [the]
    excess policies at issue here is inconsistent with application of the
    horizontal exhaustion doctrine. In so arguing, Montrose suggests
    that each of the policies contained a provision or provisions which
    14
    specifies some identifiable amount of underlying limits that must
    be exhausted before its obligation attaches.
    “More specifically, Montrose argues that each excess
    policy’s description of the underlying limit or coverage that must
    be exhausted is described with respect to its same policy period.
    While this may be true, this argument overlooks the fact that the
    present case is a continuous loss scenario; thus, Montrose’s
    contention that exhaustion should be applied vertically with
    respect to each individual policy period is undermined by the very
    authority supporting its own stacking arguments as noted by the
    California Supreme Court decision in [Continental, supra,]
    
    55 Cal.4th 186
    , which decision allows the insured to stack the
    policy limits of those policies triggered in more than one policy
    period.
    “Therefore, the stacking approach endorsed by the Supreme
    Court in Continental would direct . . . that the aggregate value of
    all underlying policies throughout the duration of a continuous
    loss must be exhausted before excess coverage is accessible to the
    insured . . . .”
    The court concluded: “The ‘other insurance’ provisions
    contained in the present excess policies must be read to require
    the exhaustion of all underlying insurance before [the excess
    insurers’] obligations to indemnify Montrose attach. The
    presence of ‘other insurance’ clauses would preclude the use of a
    vertical exhaustion approach even for those excess policies
    specifically identified in a particular underlying policy that must
    first be exhausted. [¶] The [inclusion] of such broad ‘other
    insurance’ language invokes the rules set forth in Community
    Redevelopment that horizontal exhaustion must apply absent a
    provision of the excess policy that both specifically describes and
    15
    limits the underlying insurance. [¶] Whereas here the excess
    policy included language that invokes all underlying insurance,
    no such limitation can be reasonably argued to exist. [¶] . . . [¶]
    “So in conclusion, in light of the authorities cited, the court
    concludes that the parties must employ a horizontal exhaustion
    approach, whereby the aggregate limits of underlying policies for
    the applicable policy periods must first be exhausted before any
    excess policies incur a duty to indemnify Montrose for its
    liabilities . . . .”
    V.
    Present Petition for Writ of Mandate
    Montrose filed a petition for writ of mandate in this court,
    seeking an order directing the trial court to grant Montrose’s
    motion for summary adjudication and deny the insurers’ cross-
    motion for summary adjudication. We summarily denied the
    petition. Montrose filed a petition for review. The Supreme
    Court granted review and transferred the matter to this court
    with directions to issue an order to show cause why the relief
    sought in the petition should not be granted.
    We issued an order to show cause and received
    supplemental briefing. The Continental insurers and the
    Travelers insurers filed briefs in opposition to the petition, and
    ITT LLC and Santa Fe Braun, Inc. filed an amicus curiae brief in
    support of Montrose.
    SUMMARY OF ISSUES
    Montrose urges the court to adopt what it terms an
    “elective stacking” approach. Under this approach, where a
    policyholder is liable for a continuing injury that potentially is
    covered by primary and excess policies in multiple policy years,
    the policyholder “may elect to proceed ‘vertically’ to exhaust
    16
    policies for a single coverage year, once the underlying policy
    exhaustion provisions are satisfied.” Montrose urges that
    “elective stacking” is consistent with Supreme Court precedent
    “recognizing that policyholders are entitled to look to any
    independent contract to cover the full extent of their liability (up
    to policy limits) in accordance with the terms of each individual
    policy,” as well as with the language of the relevant excess
    policies.
    The Continental insurers urge a “horizontal exhaustion”
    approach. They contend that the excess policies at issue contain
    provisions “that make them excess to vertically underlying
    policies in the same policy period plus ‘other valid and collectible’
    insurance, that is, other insurance that is not vertically
    underlying and also triggered by the same occurrence.” The
    Travelers insurers separately urge declaratory relief is
    premature because Montrose has not demonstrated that it has
    exhausted its underlying primary policies, and there is no basis
    for issuing a writ of mandate because Montrose has failed to
    demonstrate that it lacks an adequate remedy at law or is at risk
    of irreparable harm.
    As we now discuss, we reject Montrose’s “elective stacking”
    approach. Specifically, we conclude that Montrose is not entitled
    to a declaration that it may access any of the more than
    115 excess policies at issue so long as its liabilities are sufficient
    to exhaust the underlying policies for the same policy year. We
    therefore conclude that the trial court properly denied Montrose’s
    motion for summary adjudication and granted the insurers’ cross-
    motion for summary adjudication of the 32nd cause of action
    because we conclude that Montrose is not entitled to the
    declaration sought in that cause of action as a matter of law.
    17
    However, we do not adopt the trial court’s conclusion that
    all excess policies must be horizontally exhausted. Instead,
    because there is tremendous variation among the policies at
    issue, we decline to adopt a single exhaustion scheme that
    applies to Montrose’s entire coverage portfolio, and instead direct
    that each policy be interpreted according to its terms. We
    therefore conclude that the trial court erred in granting the
    Continental insurers’ motion for summary adjudication insofar as
    it sought to summarily adjudicate the issue of duty.
    STANDARD OF REVIEW
    “A motion for summary adjudication shall be granted only
    if it completely disposes of a cause of action, an affirmative
    defense, a claim for damages, or an issue of duty.” (Code Civ.
    Proc., § 437c, subd. (f)(1).) The moving party “bears an initial
    burden of production to make a prima facie showing of the
    nonexistence of any triable issue of material fact; if [the moving
    party] carries [its] burden of production, [it] causes a shift, and
    the opposing party is then subjected to a burden of production of
    [its] own to make a prima facie showing of the existence of a
    triable issue of material fact. . . . A prima facie showing is one
    that is sufficient to support the position of the party in question.”
    (Aguilar v. Atlantic Richfield Co. (2001) 
    25 Cal.4th 826
    , 850–851,
    fn. omitted.)
    We review de novo an order granting or denying a motion
    for summary adjudication. (Aguilar v. Atlantic Richfield Co.,
    supra, 25 Cal.4th at p. 860.) The trial court’s stated reasons for
    granting summary adjudication are not binding on the reviewing
    court, which reviews the trial court’s ruling, not its rationale.
    (Haering v. Topa Ins. Co. (2016) 
    244 Cal.App.4th 725
    , 732.)
    18
    DISCUSSION
    I.
    Primary and Excess Insurance
    There are two levels of insurance coverage—primary and
    excess. “Primary coverage is insurance coverage whereby, under
    the terms of the policy, liability attaches immediately upon the
    happening of the occurrence that gives rise to liability.
    [Citation.] Primary insurers generally have the primary duty of
    defense. [¶] ‘Excess’ or secondary coverage is coverage whereby,
    under the terms of the policy, liability attaches only after a
    predetermined amount of primary coverage has been exhausted.
    [Fn. omitted.] It is not uncommon to have several layers of
    secondary insurance.” (Olympic Ins. Co. v. Employers Surplus
    Lines Ins. Co. (1981) 
    126 Cal.App.3d 593
    , 597–598, some italics
    omitted; see also Community Redevelopment, supra,
    50 Cal.App.4th at pp. 337–338 [discussing primary and excess
    coverage].)
    An excess insurance policy may be written as excess to
    specifically identified coverage—i.e., to “a particular policy or
    policies (e.g., ‘excess to liability coverage provided under Aetna
    Policy No. 246789’) (see 20th Century Ins. Co. v. Liberty Mut. Ins.
    Co. (9th Cir. 1992) 
    965 F.2d 747
    , 757 (applying Calif. law)); or [¶]
    coverage provided by a particular insurer (e.g., ‘excess to the
    primary insurer, Liberty Mutual’) (see 20th Century Ins. Co. v.
    Liberty Mut. Ins. Co., supra, 965 F.2d at 757).” (Croskey et al.,
    Cal. Practice Guide: Insurance Litigation (The Rutter Group
    2017) ¶ 8:181 (Croskey).) Alternatively, an excess policy may be
    written to provide coverage “ ‘in excess of (identified primary
    policy) and the applicable limits of any other underlying
    insurance providing coverage to the insured.’ [¶] Under such a
    19
    policy, the excess insurer has no duty to defend or indemnify
    until all underlying policies available to the insured, whether or
    not listed in the excess policy, are exhausted. [See [Community
    Redevelopment, supra,] 50 Cal.App.4th [at pp.] 339–341;
    Continental Ins. Co. v. Lexington Ins. Co. (1997) 
    55 Cal.App.4th 637
    , 645].” (Croskey, supra, ¶ 8:182.)
    The relationship between primary and excess insurance (or
    multiple layers of excess insurance) is particularly complex in
    environmental injury cases where harm is alleged to have
    occurred over many years and many policy periods. Injuries of
    this kind, termed “ ‘long-tail’ ” injuries, are “a series of indivisible
    injuries attributable to continuing events without a single
    unambiguous ‘cause’ ” and produce progressive damage that
    takes place slowly over years or even decades. (Continental,
    supra, 55 Cal.4th at p. 196.) Because CGL policies typically are
    silent as to coverage for long-tail injuries, they frequently give
    rise to coverage disputes. (Ibid.)
    II.
    The Trial Court Correctly Rejected Montrose’s
    “Elective Stacking” Approach; Therefore, It
    Correctly Denied Montrose’s Motion for Summary
    Adjudication and Granted the Continental
    Insurer’s Cross-Motion for Summary
    Adjudication of the 32nd Cause of Action
    Montrose asserts that the trial court erred in
    rejecting elective stacking in favor of mandatory horizontal
    exhaustion. Specifically, Montrose contends: (1) elective
    stacking is the only approach consistent with the Supreme
    Court’s recent guidance in Continental; (2) each of the
    relevant policies contains express language stating that
    20
    coverage attaches upon exhaustion of specified underlying
    limits of lower-layer policies within the same policy period;
    and (3) elective stacking is consistent with sound public
    policy. We consider each of these issues below.
    A.     Continental Does Not Dictate “Elective
    Stacking” in This Case
    We begin by addressing Montrose’s contention that the
    result in this case is dictated by the California Supreme Court’s
    decision in Continental, supra, 
    55 Cal.4th 186
    . Montrose asserts:
    “Over the last two decades, the California Supreme Court has
    repeatedly declared the fundamental principle that a policyholder
    has the contractual right, under any insurance policy (or policies)
    triggered by a covered loss, to obtain immediate indemnification
    of its liabilities. . . . [¶] . . . [In Continental], the high court held
    that when a continuous injury triggers multiple policies, ‘each
    policy can be called upon to respond to the claim up to the full
    limits of the policy. (Id. at p. 200, emphasis added.)” Indeed,
    Montrose urges, the court in Continental “rejected the very
    scheme Defendant insurers argue[] for” and “confirm[ed] the
    policyholder’s right to choose the policy(ies) and seek to allocate
    the losses vertically or horizontally as the policyholder sees fit.”
    As we now discuss, Continental does not dictate the result
    in this case. Importantly, both the relevant policy language and
    the issues confronting the Continental court were very different
    from the language and issues before us; and nothing in
    Continental suggests that, in the context of the present case, an
    insured has an absolute right to “select which policy(ies) to access
    for indemnification in the manner they deem most efficient and
    advantageous.”
    21
    1.     Continental: Insured Liable for Long-Tail
    Claim May “Stack” Policies Issued in Different
    Policy Periods
    In Continental, supra, 
    55 Cal.4th 186
    , the Supreme Court
    considered insurers’ indemnity and defense obligations in the
    context of a long-tail environmental injury. Between 1956 and
    1972, the State of California operated an industrial waste
    disposal facility that was later discovered to have leaked
    hazardous materials. Before 1963, the state was uninsured;
    between 1964 and 1976, the state purchased ten excess CGL
    policies from different insurers. The state had drafted a master
    liability policy form that it required its insurers to use, and thus
    the relevant language of each of the policies was essentially the
    same. Specifically, each policy obligated the insurer “ ‘[t]o pay on
    behalf of the Insured all sums which the Insured shall become
    obligated to pay by reason of liability imposed by law . . . for
    damages . . . because of injury to or destruction of property,
    including loss of use thereof.’ ” (Continental, supra, at pp. 192–
    193, italics added.)
    After a federal court found the state liable for past and
    future cleanup costs associated with the disposal facility, the
    state sued several of its insurers, seeking indemnification for its
    liability in the federal action. (Continental, supra, 55 Cal.4th at
    pp. 192–193.) Following a bench trial, the superior court held
    that the state could not “stack,” or combine, policy limits across
    multiple policy periods. Instead, the state “had to choose a single
    policy period for the entire liability coverage, and it could recover
    only up to the total policy limits in effect during that policy
    period.” (Id. at p. 193.)
    22
    The Supreme Court disagreed, concluding that the
    language of the policies at issue permitted the stacking of policy
    limits across multiple policy periods, so as to effectively create
    “ ‘ “one giant uber policy” with a coverage limit equal to the sum
    of all purchased insurance policies.’ ” (Id. at p. 200–201, italics
    added.)
    The Supreme Court began its analysis by reiterating basic
    principles of insurance interpretation: “In general, interpretation
    of an insurance policy is a question of law that is decided under
    settled rules of contract interpretation. [Citations.] ‘ “While
    insurance contracts have special features, they are still contracts
    to which the ordinary rules of contractual interpretation apply.”
    [Citations.] ‘The fundamental goal of contractual interpretation
    is to give effect to the mutual intention of the parties.’ [Citation.]
    ‘Such intent is to be inferred, if possible, solely from the written
    provisions of the contract.’ [Citation.] ‘If contractual language is
    clear and explicit, it governs.’ [Citation.] ‘ “The ‘clear and
    explicit’ meaning of these provisions, interpreted in their
    ‘ordinary and popular sense,’ unless ‘used by the parties in a
    technical sense or a special meaning is given to them by usage’
    ([Civ. Code,] § 1644), controls judicial interpretation. [Citation.]”
    [Citations.]’ [Citation.] ” (Continental, supra, 55 Cal.4th at
    pp. 194–195.)
    The court then addressed the “all sums” language of the
    relevant policies, explaining that such language “obligate[s] the
    insurers to pay all sums for property damage attributable to the
    [contaminated] site, up to their policy limits, if applicable, as long
    as some of the continuous property damage occurred while each
    policy was ‘on the loss.’ ” (Continental, supra, 55 Cal.4th at
    p. 200.) This coverage “extends to the entirety of the ensuing
    23
    damage or injury [citation], and best reflects the insurers’
    indemnity obligations under the respective policies, the insured’s
    expectations, and the true character of the damages that flow
    from a long-tail injury.” (Ibid.)
    Continental determined that the policies at issue enabled
    the insured “to stack the consecutive policies and recover up to
    the policy limits of the multiple plans. ‘Stacking’ generally refers
    to the stacking of policy limits across multiple policy periods that
    were on a particular risk. In other words, ‘Stacking policy limits
    means that when more than one policy is triggered by an
    occurrence, each policy can be called upon to respond to the claim
    up to the full limits of the policy.’ [Citation.] ‘When the policy
    limits of a given insurer are exhausted, [the insured] is entitled
    to seek indemnification from any of the remaining insurers [that
    were] on the risk . . . .’ [Citations.] The all-sums-with-stacking
    indemnity principle . . . ‘effectively stacks the insurance coverage
    from different policy periods to form one giant “uber-policy” with
    a coverage limit equal to the sum of all purchased insurance
    policies. Instead of treating a long-tail injury as though it
    occurred in one policy period, this approach treats all the
    triggered insurance as though it were purchased in one policy
    period. The [insured] has access to far more insurance than it
    would ever be entitled to within any one period.’ [Citation.] The
    all-sums-with-stacking rule means that the insured has
    immediate access to the insurance it purchased. It does not put
    the insured in the position of receiving less coverage than it
    bought. It also acknowledges the uniquely progressive nature of
    long-tail injuries that cause progressive damage throughout
    multiple policy periods. [Citation.]” (Continental, supra,
    55 Cal.4th at pp. 200–201.)
    24
    Continental emphasized that “absent antistacking
    provisions, statutes that forbid stacking, or judicial intervention,
    ‘standard policy language permits stacking.’ ” (Continental,
    supra, 55 Cal.4th at p. 201.) The court therefore concluded that
    “the policies at issue here, which do not contain antistacking
    language, allow for its application. . . .” (Id. at p. 201, italics
    added.) The court noted, however, that there exists a “significant
    caveat” to all-sums-with-stacking indemnity allocation—i.e., that
    an insurer “may avoid stacking by specifically including an
    ‘antistacking’ provision in its policy. Of course, in the future,
    contracting parties can write into their policies whatever
    language they agree upon, including limitations on indemnity,
    equitable pro rata coverage allocation rules, and prohibitions on
    stacking.” (Id. at p. 202.)
    2.    What Continental Did and Did Not Decide
    As the foregoing discussion makes clear, the issue before
    the court in Continental was very different from the issue
    presented by the present petition. Before the court in
    Continental was the question of whether the insured could access
    policies in effect during multiple triggered policy periods, as the
    insured contended, or whether it could access only those policies
    that covered a single policy period, as urged by the insurers. The
    issue before us, in contrast, is not whether an insured can access
    policies written for different policy years (it can), but the order or
    sequence in which it may or must do so.
    Moreover, as we have said, the court’s analysis in
    Continental was based on the language of the particular policies
    before it in that case, and specifically the insurers’ promises “ ‘[t]o
    pay on behalf of the Insured all sums which the Insured shall
    become obligated to pay by reason of liability imposed by law . . .
    25
    for damages . . . because of injury to or destruction of property,’ ”
    up to specified policy limits. (Continental, supra, 55 Cal.4th at
    p. 193, italics added.) In contrast, many of the excess policies
    relevant to our analysis do not include “all sums” language, and
    thus the high court’s analysis of the “all sums” language has
    limited application here.
    Further, Continental did not, as Montrose asserts,
    announce a general principle that insureds covered by multiple
    policies are entitled to “select which policy(ies) to access for
    indemnification in the manner they deem most efficient and
    advantageous.” Indeed, Continental did not announce any
    general principles applicable to all insureds and all policies.
    Instead, it reaffirmed the principle that insurance policies must
    be interpreted according to their terms, even if alternative
    allocation schemes might be more desirable. (See Continental,
    supra, 55 Cal.4th at p. 199 [“Although some states have
    concluded, as the insurers urge in this case, that pro rata
    coverage would be more fair and equitable when compared to all
    sums allocation, we are constrained by the language of the
    applicable policies here.”].)
    Finally, while Continental held that each “triggered” policy
    may be called upon to respond to a claim (Continental, supra,
    55 Cal.4th at p. 200), it did not consider when a higher-layer
    excess policy is “triggered” in the context of a long-tail
    environmental injury. That is, Continental discussed the “trigger
    of coverage” issue temporally, explaining that “ ‘[t]he issue is
    largely one of timing—what must take place within the policy’s
    effective dates for the potential of coverage to be “triggered”? ’ ”
    (Id. at p. 196.) Because it was not called upon to do so, the court
    in Continental did not consider the aspect of “trigger of coverage”
    26
    before us in this case—what lower-layer excess policies must be
    exhausted before a higher-layer excess policy is triggered.
    In short, while Continental provides a general framework
    for our analysis, it provides limited guidance on the specific
    question before us: Whether Montrose may access higher-level
    excess insurance before exhausting lower-level excess insurance
    written for different policy periods. As Continental directs, we
    turn to the language of the relevant policies to decide that
    question.
    B.    The Language of the Excess Insurance Policies Does
    Not Mandate “Elective Stacking”
    1.    The Policies’ “Plain Language”
    Montrose acknowledges that the starting point of policy
    interpretation is “the ‘plain language’ of the written provisions of
    the insurance contract,” and it asserts that each of the excess
    policies at issue contains “express language” stating “that
    coverage thereunder attaches upon the exhaustion of a specified
    amount of underlying insurance issued in the same policy year.”
    (Italics added.) The latter assertion is the linchpin of Montrose’s
    plain language analysis: If Montrose is correct that the policies
    provide for coverage as soon as lower-layer policies within the
    same policy period are exhausted, then elective stacking
    necessarily follows.
    The problem with Montrose’s analysis is that it is largely
    unsubstantiated by the policy language. That is, while Montrose
    repeatedly asserts that the excess policies attach upon the
    exhaustion of lower layer policies within the same policy period,
    it does not identify the provisions that supposedly have that
    effect.
    27
    Our analysis of the policies, moreover, leads us to conclude
    that many of the policies attach not upon exhaustion of lower-
    layer policies within the same policy period, but rather upon
    exhaustion of all available insurance. A few examples will
    illustrate the point:
    (1)    American Centennial Policies Nos. XC-00-03-64, XC-
    00-06-75, and XC-00-12-16. The insuring agreements of these
    policies state that the insurer “agrees to pay on behalf of the
    insured the ultimate net loss in excess of the retained limit[3]
    hereinafter stated.” The declarations then identify the
    underlying policies to which the American Centennial policies are
    specifically in excess (the “scheduled policies”); for example, for
    policy year 1980 to 1981, the American Centennial policy
    references a Canadian Universal CGL policy, written for policy
    period March 1980 through March 1981, with a combined single
    limit of $1,000,000.
    Focusing on only the insuring agreements and declarations,
    Montrose would have us conclude that the American Centennial
    policies attach upon the exhaustion of the scheduled policies—in
    the example provided above, when Montrose’s liabilities exceed
    $1,000,000, thus exhausting the limits of the Canadian Universal
    policy. But that interpretation ignores other relevant policy
    provisions, including the following:
    The “retained limit” clause: This clause provides: “ ‘[T]he
    company’s liability shall be only for the ultimate net loss in
    excess of the insured’s retained limit defined as the greater of:
    3      “Retained limit” “refers to a specific sum or percentage of
    loss that is the insured’s initial responsibility and must be
    satisfied before there is any coverage under the policy.” (Croskey,
    supra, ¶ 7:384.)
    28
    [¶] . . . the total of the applicable limits of the underlying policies
    listed in [the declarations] hereof, and the applicable limits of any
    other underlying insurance collectible by the insured.’ ” (Italics
    added.) This clause thus expressly states that the excess
    insurer’s liability is in excess of the identified underlying
    insurance and the applicable limits of any other underlying
    insurance collectible by the insured.
    The “other insurance” clause: This clause states: “ ‘If other
    collectible insurance . . . is available to the insured covering a loss
    also covered hereunder (except insurance purchased to apply in
    excess of the sum of the retained limit and the limit of liability
    hereunder) the insurance hereunder shall be in excess of and not
    contribute with, such other insurance.’ ” This clause thus
    provides that the American Centennial policies are excess to both
    scheduled and unscheduled policies.
    (2)    Continental Policies Nos. RDX 030 807 62 18, RDX
    8893542, RDX 8936616 and RDX 8936617, and Columbia
    Policies Nos. RDX 1864012 and RDX 3652015. The
    indemnification provisions of these policies require the insurers
    “ ‘[t]o indemnify the insured for the amount of loss which is in
    excess of the applicable limits of liability of the underlying
    insurance [identified in the schedule of primary and umbrella[4]
    4      “Umbrella policies are usually excess policies in the sense
    that they afford coverage that is excess over underlying
    insurance. [Citations.] [¶] However, an umbrella policy may
    also provide coverage for losses not covered by any underlying
    insurance; and as to those losses, the umbrella policy is primary
    [citation]. Umbrella policies may thus fill gaps in coverage both
    vertically (by providing excess coverage) and horizontally (by
    providing primary coverage for losses covered by the excess
    policy).” (Croskey, supra, ¶ 8:203.)
    29
    coverage].” The schedules of primary and umbrella coverage
    identify the underlying policies to which the Continental and
    Columbia policies are specifically in excess; for example, policy
    no. RDX 030 807 62 18 references a primary policy written by
    INA, as well as three umbrella policies written by Lloyds and
    Home Insurance.
    Montrose would have us conclude that Continental’s and
    Columbia’s policies attach immediately upon the exhaustion of
    the policies specifically identified in the schedule of primary and
    umbrella coverage. But that analysis ignores the other relevant
    policy provisions, including the following:
    Definition of “loss”: Continental’s and Columbia’s policies
    define “loss” (as used in the indemnification provisions) as “ ‘the
    sums paid as damages in settlement of a claim or in satisfaction
    of a judgment for which the insured is legally liable, after making
    deductions for all recoveries, salvages and other insurances
    (whether recoverable or not) other than the underlying insurance
    and excess insurance purchased specifically to be in excess of this
    policy.’ ” (Italics added.) These policies thus define loss in terms
    of other insurance.
    “Other insurance” clauses: The “other insurance” clauses
    state: “ ‘If, with respect to a loss covered hereunder, the insured
    has other insurance, whether on a primary, excess or contingent
    basis, there shall be no insurance afforded hereunder as respects
    such loss; provided, that if the applicable limit of liability of this
    policy is greater than the applicable limit of liability provided by
    the other insurance, this policy shall afford excess insurance over
    and above such other insurance in an amount sufficient to give
    the insured, as respects the layer of coverage afforded by this
    policy, a total limit of liability equal to the applicable limit of
    30
    liability afforded by this policy.’ ” This provision “ ‘does not apply
    with respect to the underlying insurance or excess insurance
    purchased specifically to be in excess of this policy.’ ” It thus
    expressly states that the Continental and Columbia policies shall
    not cover losses for which the insured has other insurance.
    We caution that the foregoing discussion addresses just a
    few of the excess policies at issue, and thus nothing we have said
    should be understood to apply to all of the excess policies before
    us. To the contrary, there is tremendous variation among the
    relevant policies, and each must be interpreted according to its
    own language.5 There may well be some policies that, as
    Montrose argues, are triggered by the exhaustion of only the
    underlying scheduled insurance for the same policy year. To
    demonstrate that it is entitled to elective stacking as to its entire
    policy portfolio, however, Montrose must show that each policy is
    susceptible of being read in this fashion. It plainly has not done
    so.
    5      We disagree with Montrose’s contention that “[w]hile there
    are various nuances and variations in the insuring agreement for
    each of the Policies, these differences do not change the basic
    grant of coverage . . . or materially alter the determination of the
    proper exhaustion methodology.” As we have said, there is
    significant diversity among the various excess policies—the
    relevant language of which fills approximately 90 pages of
    Montrose’s appendix.
    31
    2.    Case Law Establishes That “Other Insurance”
    Provisions Must Be Given Effect According to Their
    Terms
    (a)   Community Redevelopment
    Our conclusion that (at least some of) the policies before us
    are excess to lower-lying policies written in both the same and
    other years is consistent with the conclusion of Community
    Redevelopment, supra, 
    50 Cal.App.4th 329
    . There, the insured
    was a developer who constructed housing complexes on
    improperly filled land. (Id. at p. 333–334.) The insured had
    purchased primary insurance policies from United Pacific
    Insurance Company (United) for policy years 1982–1984, and
    from State Farm Fire and Casualty Insurance Company (State
    Farm) for policy year 1985–1986; for policy year 1985–1986, the
    developer also purchased an excess policy from Scottsdale
    Insurance Company (Scottsdale). (Id. at p. 334.) When the
    insured was sued by homeowners for continuing property damage
    that spanned these policy periods, it tendered claims to all three
    insurers.
    After State Farm’s primary policy limits were exhausted, a
    dispute arose between United and Scottsdale as to which insurer
    was responsible to the developer for the remaining defense costs.
    United argued that Scottsdale’s policy was excess to State Farm’s
    primary policy, and thus Scottsdale’s duty to defend arose as soon
    as the State Farm policy was exhausted. (Community
    Redevelopment, supra, 50 Cal.App.4th at p. 337.) Scottsdale
    disagreed, urging that its insurance was excess to all other
    primary insurance available to the developer.
    To resolve the issue, the court reviewed the language of the
    Scottsdale excess policy. The court noted that there was “no
    32
    dispute” that Scottsdale’s $5 million coverage was purchased as
    excess to the $1 million primary policy issued by State Farm.
    However, “the express provisions of the [excess] policy further
    provide that Scottsdale’s liability was also excess to ‘the
    applicable limits of any other underlying insurance collectible by
    the [insured parties].’ (Italics added.) This express description
    as to the scope of Scottsdale’s excess coverage is entirely
    consistent with, and is reinforced by, other policy language
    dealing with Scottsdale’s duty to defend and the impact of ‘other
    insurance.’ Scottsdale agreed to defend its insured provided that
    ‘no other insurance affording a defense or indemnity against such
    a suit is available.’ The policy also provided that the insurance
    afforded by the policy ‘shall be excess insurance over any other
    valid and collectible insurance available to the [insured parties]
    whether or not described in the Schedule of Underlying
    Insurance’ (which schedule listed State Farm’s $1 million
    policy).” (Community Redevelopment, supra, 50 Cal.App.4th at
    p. 338.) Thus, applying “settled rules of policy construction,” the
    court concluded that Scottsdale’s exposure was excess to all other
    primary insurance available to the developer. (Id. at pp. 338–
    339; see also Padilla Construction Co. v. Transportation Ins. Co.
    (2007) 
    150 Cal.App.4th 984
     [under its plain language, excess
    policy was not triggered until all primary insurance was
    exhausted, including primary insurance written in different
    policy years]; Olympic Ins. Co. v. Employers Surplus Lines Ins.
    Co. (1981) 
    126 Cal.App.3d 593
    , 600 [“ ‘[When] a policy which
    provides excess insurance above a stated amount of primary
    insurance contains provisions which make it also excess
    insurance above all other insurance which contributes to the
    33
    payment of the loss together with the specifically stated primary
    insurance, such clause will be given effect as written.’ ”].)
    Montrose urges that Community Redevelopment is not
    relevant to our analysis because that case involved primary
    coverage and “did [not] announce any rule about a policyholder’s
    right to access higher-lying coverage before the exhaustion of
    excess policies in different policy periods.”6 We do not agree.
    While Montrose is correct that the underlying layer of insurance
    in Community Redevelopment was a primary layer, rather than
    a lower-lying excess layer, Montrose suggests no reason why we
    should differently interpret first-layer excess policies (that is,
    excess policies immediately above primary policies) and higher-
    level excess policies (excess policies immediately above other
    excess policies). Montrose also suggests that Community
    Redevelopment is not relevant because it “had nothing to do with
    a policyholder’s right to indemnity coverage,” but rather
    addressed the duty to defend. In fact, although the specific
    question before the court in Community Redevelopment was
    whether the excess insurer had an obligation “to ‘drop down’ and
    provide a defense,” the answer to that question depended on
    6     Montrose also argues, citing Montgomery Ward & Co. v.
    Imperial Casualty & Indemnity Co. (2000) 
    81 Cal.App.4th 356
    ,
    369 (Montgomery Ward), that “California courts that have been
    asked by insurers to expand Community Redevelopment beyond
    the contours of primary insurance have refused to do so.”
    However, Montgomery Ward concerned the obligations of excess
    insurers to an insured in the context of a self-insured retention,
    which the court concluded was not “ ‘other collectible insurance
    with any other insurer’ ” within the meaning of the policy
    language before it (id. at pp. 366–367); it therefore is irrelevant to
    our analysis.
    34
    whether the excess insurer’s exposure for either defense or
    indemnity was excess to all other lower-lying policies, or to only
    the lower-lying policy to which the excess policy specifically
    referred—the very issue before us in this case. (Community
    Redevelopment, supra, 50 Cal.App.4th at pp. 332, 336–339.)
    (b)     Dart Industries, Inc. v. Commercial
    Union Ins. Co. Does Not Compel Us to Ignore
    the Policies’ “Other Insurance” Provisions
    Montrose acknowledges that many of the policies purport to
    be excess to “other insurance,” but citing Dart Industries, Inc. v.
    Commercial Union Ins. Co. (2002) 
    28 Cal.4th 1059
     (Dart),
    Montrose urges that “other insurance” clauses are relevant only
    to “the specific question of how to allocate (or ‘apportion’) liability
    disputes ‘among multiple insurers’ after the policyholder is fully
    indemnified”—not to “ ‘the insurers’ obligations to the
    policyholder.’ ” In other words, Montrose contends, “ ‘[O]ther
    insurance’ clauses govern the rights and obligations of insurers
    covering the same risk vis-à-vis one another, but do not affect a
    policyholder’s right to recovery under those policies.”
    Montrose’s assertion about “other insurance” clauses finds
    no support in Dart. Dart concerned claims made by women
    injured as a result of prenatal exposure to diethylstilbestrol
    (DES) manufactured by Dart from the 1940’s through the 1960’s.
    During some of those years, Dart was covered by a CGL policy
    issued by Commercial Union Insurance Company (Commercial
    Union), but all copies of the policy had been lost. (Dart, supra,
    28 Cal.4th at pp. 1064–1065.) Commercial Union urged, among
    other issues, that an “other insurance” clause might reduce or
    extinguish its liability, and thus that Dart had to establish the
    terms of the lost policy’s “other insurance” clause in order to
    35
    trigger Commercial Union’s duties to defend and indemnify. One
    of the issues on appeal, therefore, was whether Dart’s inability to
    prove the precise terms of the “other insurance” clause was fatal
    to its claim. (Id. at pp. 1078-1079.)
    The court held that Dart’s ignorance of the language of the
    policy’s “other insurance” clause did not relieve Commercial
    Union of its policy obligations. The court noted that “the modern
    trend is to require equitable contributions on a pro rata basis
    from all primary insurers regardless of the type of ‘other
    insurance’ clause in their policies.” (Dart, 
    supra,
     28 Cal.4th at
    p. 1080, italics added.) It was undisputed that Commercial
    Union was a primary insurer during the relevant time period.
    Thus, an “other insurance” clause—whatever its terms—was
    irrelevant to Commercial Union’s obligation to provide primary
    coverage to its insured: “ ‘When multiple policies are triggered on
    a single claim, the insurers’ liability is apportioned pursuant to
    the “other insurance” clauses of the policies [citation] or under
    the equitable doctrine of contribution [citations]. That
    apportionment, however, has no bearing upon the insurers’
    obligations to the policyholder. . . . The insurers’ contractual
    obligation to the policyholder is to cover the full extent of the
    policyholder’s liability (up to the policy limits).’ [Citations.] This
    principle is consistent with ‘the settled rule that an insurer on
    the risk when continuous or progressively deteriorating damage
    or injury first manifests itself remains obligated to indemnify the
    insured for the entirety of the ensuing damage or injury.’
    [Citation.]” (Ibid, italics added.)
    Montrose relies on the italicized language to suggest that
    references to “other insurance” in its policies are relevant only to
    the insurers’ obligations to one another, not to the insurers’
    36
    obligations to it. But in so urging, Montrose ignores a key
    difference between Dart and the present case—namely, that the
    insurer in Dart was a primary insurer, while the insurers in the
    present case are excess insurers. The difference between primary
    and excess insurance in this context is material. In Dart, the
    “other insurance” clause was held not to extinguish the insurer’s
    duty to the insured under the relevant primary policies because
    such duty attached “ ‘when continuous or progressively
    deteriorating damage or injury first manifests itself’ ” and
    covered “ ‘the full extent of the policyholder’s liability (up to the
    policy limits).’ ” (Dart, supra, 28 Cal.4th at p. 1080.) The excess
    policies at issue in the present case, however, attach only after
    other identified insurance is exhausted, not immediately upon
    the occurrence giving rise to liability. (Croskey, supra, at
    ¶ 8:176–8:177.) Thus, because exhaustion of underlying
    insurance is an explicit prerequisite for the attachment of excess
    insurance—and because an “other insurance” clause may define
    the insurance that must be exhausted before the excess insurance
    attaches—Dart’s statement that apportionment among insurers
    has no bearing on the insurers’ obligations to the policyholder
    simply does not apply in the present context.
    The distinction between primary and excess policies for
    purposes of giving effect to “other insurance” clauses is aptly
    illustrated by Carmel Development Co. v. RLI Ins. Co. (2005)
    
    126 Cal.App.4th 502
     (Carmel). That case involved excess CGL
    policies issued by RLI Insurance Company (RLI) and Fireman’s
    Fund Insurance Company (Fireman’s Fund). (Id. at p. 506.)
    After the limits of the primary policies were exhausted, a dispute
    arose between RLI and Fireman’s Fund as to whether RLI was
    37
    required to contribute on an equal basis with Fireman’s Fund to
    a settlement entered into by the insured.
    The trial court held that because the two excess policies
    had competing “other insurance” clauses, the excess insurers had
    to contribute to the settlement on a pro rata basis. (Carmel,
    supra, 126 Cal.App.4th at p. 507.) The Court of Appeal reversed.
    It agreed with the trial court that both policies contained similar
    “other insurance” clauses, and it said it thus would uphold the
    trial court’s decision if the “other insurance” clauses were
    considered in isolation. The Carmel court declined to read the
    clauses in isolation, however. It instead undertook “a broader
    examination of each policy to ascertain the context in which the
    ‘other insurance’ provisions appeared.” (Id. at p. 509.)
    The Carmel court noted that Fireman’s Fund’s insuring
    agreement promised to pay the insured “ ‘those sums in excess of
    Primary Insurance’ ” described in the “ ‘Limits of Insurance.’ ” In
    contrast, RLI’s insuring agreement promised to pay the insured’s
    “ultimate net loss in excess of . . . the applicable limits of
    scheduled underlying insurance . . . plus the limits of any
    unscheduled underlying insurance . . . .’ ” (Carmel, supra,
    126 Cal.App.4th at p. 510, italics added.) Based on this language,
    the Carmel court concluded that RLI and Fireman’s Fund did not
    place themselves in identical positions with respect to other
    insurance. It explained: “Fireman’s Fund undertook to provide
    coverage immediately upon exhaustion of [the specifically
    identified primary insurer’s] policy limits, whereas RLI obligated
    itself to step in only when the limits of both the [specifically
    identified primary] policy and all other available coverage—
    primary and excess—were exceeded.” (Carmel, supra, at
    pp. 510–511.) Thus, “the overall intent and purpose of the two
    38
    policies at issue here can be discerned from their respective
    insuring terms read in context and in light of the entire policy in
    which they appear. Fireman’s Fund provided coverage
    specifically excess to the underlying primary policy, whereas RLI
    was liable for claims in excess of any other insurance. Because
    the two policies did not operate at the same level of coverage, it
    was irrelevant that they both contained excess-only ‘other
    insurance’ clauses. As the Fireman’s Fund policy limit was not
    exceeded by the [underlying] settlement, RLI had no duty to
    contribute to the indemnification of [the insured].” (Id. at
    pp. 516–517.)
    Carmel makes clear that references to “other insurance”
    may play different roles in different policies. Where two (or
    more) policies are at the same level for the same risk (e.g., both
    primary or both excess) and contain conflicting “other insurance”
    provisions purporting to be excess over all other available
    insurance, courts may refuse to give effect to those provisions
    and, instead, require each to contribute to the costs of defense or
    indemnity on a pro rata basis. (Carmel, supra, 126 Cal.App.4th
    at p. 508.) Under other circumstances, however, “other
    insurance” clauses may be relevant to determining whether two
    policies provide the same level of coverage—and, thus, the order
    in which excess policies attach.7
    7      Montrose also contends that giving effect to “other
    insurance” provisions in the context of determining a
    policyholder’s right to recovery “would lead to the absurd result
    that Montrose could not obtain coverage under any Policy,
    because each Policy purports to require Montrose to first exhaust
    all ‘other valid and collectible insurance’ in other policy periods.”
    The claim is without merit. It is true, as Montrose notes, that
    where multiple policies contain “other insurance” clauses
    39
    C.     Montrose’s Public Policy Claims Are Without
    Merit
    Notwithstanding the foregoing, Montrose contends that
    there are multiple reasons why a rejection of elective stacking
    would be “inconsistent with sound public policy.” However,
    public policy is not an appropriate basis for re-writing the policy
    language: As our Supreme Court has said, “[T]he pertinent
    policies provide what they provide. [The insured] and the
    insurers were generally free to contract as they pleased.
    [Citation.] They evidently did so. They thereby established what
    was ‘fair’ and ‘just’ inter se. We may not rewrite what they
    themselves wrote.” (Aerojet-General Corp. v. Transport
    Indemnity Co. (1997) 
    17 Cal.4th 38
    , 75.)
    In any event, Montrose’s public policy claims are without
    merit for the reasons that follow:
    Montrose first urges that mandatory horizontal exhaustion
    obligates the policyholder to obtain coverage from policies it may
    not wish to access. We do not agree that our holding in this case
    has the effect of “obligating” any policyholder to seek
    indemnification under any particular policy. All we hold today is
    that insureds must exhaust lower layers of coverage before
    accessing higher layers of coverage if the language of the excess
    purporting to be excess to one another such that honoring the
    clauses would deprive the insured of coverage, “the conflicting
    clauses will be ignored and the loss prorated among the
    insurers.” (Fireman’s Fund Ins. Co. v. Maryland Casualty Co.
    (1998) 
    65 Cal.App.4th 1279
    , 1304–1305.) However, Montrose has
    not demonstrated either that each of the policies at issue has an
    “other insurance” clause, or that giving effect to the “other
    insurance” clauses will deprive it of coverage.
    40
    policies so requires—a result hardly inconsistent with sound
    public policy.
    Montrose next argues that mandatory horizontal
    exhaustion penalizes policyholders for their “prudent decision” to
    purchase additional coverage. Not so. Horizontal exhaustion
    dictates only the sequence in which policies are accessed, not the
    total coverage available to the insured.8 There is nothing unfair
    about requiring an insured to access policies in the manner their
    provisions dictate. (E.g., Continental, supra, 55 Cal.4th at p. 199
    [in allocating losses across multiple policies, court is “constrained
    by the language of the applicable policies,” even if another
    allocation scheme “would be more fair and equitable”].)
    Montrose argues finally that mandatory horizontal
    exhaustion is “unworkable in practice” because of the complexity
    of its coverage portfolio. We do not doubt that allocating more
    than $200 million in liability across more than 100 policies
    covering nearly 25 years is likely to be a complicated process.
    That complexity, however, is not relevant to our analysis, as we
    cannot, in the service of expediency, impose obligations that are
    inconsistent with the terms of the contracts Montrose itself
    negotiated.
    D.    Conclusion: The Trial Court Properly Denied
    Montrose’s Motion for Summary Adjudication of the
    32nd Cause of Action
    Having concluded that the trial court properly rejected
    Montrose’s “elective stacking” approach, we now consider the
    8     Indeed, Montrose concedes that the hundreds of millions of
    dollars of excess coverage the policies at issue collectively provide
    “should be sufficient to fully indemnify Montrose’s liability
    incurred in U.S. v. Montrose.”
    41
    effect of this conclusion on Montrose’s motion for summary
    adjudication of the 32nd cause of action.
    To reiterate, the 32nd cause of action sought a declaration
    that “a. In order to seek indemnification under the Defendant
    Insurers’ excess policies, Montrose need only establish that its
    liabilities are sufficient to exhaust the underlying policy(ies) in
    the same policy period, and is not required to establish that all
    policies insuring Montrose in every policy period (including
    policies issued to cover different time periods both before and
    after the policy period insured by the targeted policy) with limits
    of liability less than the attachment point of the targeted policy,
    have been exhausted; and [¶] b. Montrose may select the manner
    in which [to] allocate its liabilities across the policy(ies) covering
    such losses.”
    To be entitled to summary adjudication of the 32nd cause of
    action, Montrose must demonstrate that the judicial declaration
    it sought applies not just to some of the excess policies, but to all
    of them. For the reasons discussed, while such a declaration may
    be appropriate with respect to some of the policies—an issue we
    do not reach—such broad relief manifestly could not apply to all
    of them. Therefore, the trial court did not err in denying
    Montrose’s motion for summary adjudication of the 32nd cause of
    action.9
    9      The Travelers insurers, joined by the Continental insurers,
    urge that Montrose’s request for summary adjudication is
    improper because it sought a ruling that “would excuse it from
    making the required showing for exhaustion” under California
    law: “Specifically, Montrose sought a declaration that, in order to
    seek indemnification under the defendant insurers’ excess
    policies, Montrose ‘need only establish that its liabilities are
    sufficient to exhaust’ the insurance underlying the excess
    42
    Having concluded that the trial court properly denied
    Montrose’s motion for summary adjudication of the 32nd cause of
    action, we readily conclude that the court properly granted the
    insurer’s cross-motion for summary adjudication of that cause of
    action. Montrose’s and the Continental insurers’ competing
    motions for summary adjudication of the 32nd cause of action
    were mirror images of one another. Because Montrose was not
    entitled to the declaratory relief it sought as a matter of law,
    summary adjudication of the 32nd cause of action in favor of the
    Continental insurers was warranted.
    III.
    The Present Record Does Not Support a
    Universal “Horizontal Exhaustion” Approach;
    Thus, the Trial Court Erred in Granting the
    Insurers’ Motion on the Issue of Duty
    We now reach the final issue raised in this writ proceeding:
    whether the Continental insurers were entitled to summary
    adjudication on the issue of duty. To repeat, the Continental
    insurers sought a declaration that: “All underlying policy limits
    across the years of continuing damage must be exhausted by
    payment of covered claims before any of the Insurers’ excess
    policies ha[s] a duty to pay covered claims.”
    As we have said, California law requires that insurance
    contracts be interpreted according to their terms, and there is
    tremendous variation among the terms of the excess policies at
    policy(ies) it is targeting, not that Montrose has actually
    exhausted that underlying insurance or even that the terms of
    the underlying insurance would cover Montrose’s liabilities.”
    Because we have concluded for other reasons that Montrose is not
    entitled to summary adjudication, we need not reach this issue.
    43
    issue in this matter. Further, although the parties have
    stipulated as to some of the language of the relevant policies,
    they did not provide the trial court, and have not provided this
    court, with all of the policy language or with copies of the policies
    themselves. The absence of these policies makes it impossible for
    us to “ ‘interpret [policy] language in context, with regard to its
    intended function in the policy.’ [Citation.]” (Hartford Casualty
    Ins. Co. v. Swift Distribution, Inc. (2014) 
    59 Cal.4th 277
    , 288,
    italics added.)
    Additionally, some of the policies “ ‘follow form’ ”—i.e.,
    incorporate the provisions of the immediately underlying policies
    (Fuller-Austin Insulation Co. v. Highlands Ins. Co. (2006)
    
    135 Cal.App.4th 958
    , 967)—but the insurers have not provided us
    with all of the underlying policies or, indeed, made clear which
    policies apply in each policy year. For example, American
    Centennial policy no. CC-00-76-47 provides: “Except as may be
    inconsistent with this Policy, the coverage provided by this Policy
    shall follow the insuring agreements, conditions and exclusions of
    the underlying insurance (whether primary or excess) immediately
    preceding the layer of coverage provided by this Policy, including
    any change by endorsements.” (Italics added.) We cannot
    determine from the information provided, however, the
    “underlying insurance” to which this policy refers.
    For these reasons, we cannot conclude that each of the
    more than 115 policies at issue requires “horizontal exhaustion”
    of the underlying policy layers for each policy year. Accordingly,
    the Continental insurers were not entitled to summary
    adjudication on the issue of duty.
    44
    DISPOSITION
    The petition for writ of mandate is granted in part and
    denied in part. The respondent superior court is directed to
    vacate the portion of its order granting the Continental insurers’
    motion for summary adjudication on the issue of duty, and to
    enter a new and different order denying their cross-motion for
    summary adjudication on the issue of duty; in all other respects
    (and specifically insofar as it challenges the court’s summary
    adjudication of the 32nd cause of action), the writ petition is
    denied. The cause is remanded to the respondent superior court
    for further proceedings consistent with this opinion. The parties
    shall bear their own costs in this proceeding. (Cal. Rules of
    Court, rule 8.493.)
    CERTIFIED FOR PUBLICATION
    EDMON, P. J.
    We concur:
    ALDRICH, J.   *
    LAVIN, J.
    *      Retired Associate Justice of the Court of Appeal, Second
    Appellate District, assigned by the Chief Justice pursuant to
    article VI, section 6 of the California Constitution.
    45