Title: Montrose Chemical Corp. of California v. Superior Court

State: california

Issuer: California Supreme Court

Document:

IN THE SUPREME COURT OF 
CALIFORNIA 
 
MONTROSE CHEMICAL CORPORATION  
OF CALIFORNIA, 
Petitioner, 
v. 
THE SUPERIOR COURT OF LOS ANGELES COUNTY, 
Respondent; 
CANADIAN UNIVERSAL INSURANCE 
COMPANY, INC., et al., 
Real Parties in Interest. 
 
S244737 
 
Second Appellate District, Division Three 
B272387 
 
Los Angeles County Superior Court 
BC005158 
 
 
 
April 6, 2020 
 
Justice Kruger authored the opinion of the Court, in which 
Chief Justice Cantil-Sakauye and Justices Liu, Cuéllar, 
Groban, Elia,* and Brown** concurred. 
 
                                       
* 
Associate Justice of the Court of Appeal, Sixth Appellate 
District, assigned by the Chief Justice pursuant to article VI, 
section 6 of the California Constitution. 
** 
Associate Justice of the Court of Appeal, First Appellate 
District, Division Four, assigned by the Chief Justice pursuant 
to article VI, section 6 of the California Constitution. 
1 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA 
v. SUPERIOR COURT 
S244737 
 
Opinion of the Court by Kruger, J. 
 
Montrose Chemical Corporation (Montrose) was sued for 
causing continuous environmental damage in the Los Angeles 
area between 1947 and 1982 and subsequently entered into 
partial consent decrees to resolve various claims.  Montrose now 
seeks to tap its liability insurance to cover amounts it owes in 
connection with those claims.  For each policy year from 1961 to 
1985, Montrose had secured primary insurance and multiple 
layers of excess insurance.  This case concerns the sequence in 
which Montrose may access the excess insurance policies 
covering this period.   
Montrose argues it is entitled to coverage under any 
relevant policy once it has exhausted directly underlying excess 
policies for the same policy period.  The insurers, by contrast, 
argue that Montrose may call on an excess policy only after it 
has exhausted every lower level excess policy covering the 
relevant years.  Reading the insurance policy language in light 
of background principles of insurance law, and considering the 
reasonable expectations of the parties, we agree with Montrose:  
It is entitled to access otherwise available coverage under any 
excess policy once it has exhausted directly underlying excess 
policies for the same policy period.  An insurer called on to 
provide indemnification may, however, seek reimbursement 
from other insurers that would have been liable to provide 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
2 
coverage under excess policies issued for any period in which the 
injury occurred. 
I. 
 
We have previously recounted the basic facts underlying 
this dispute.  (See Montrose Chemical Corp. v. Superior Court 
(1993) 6 Cal.4th 287, 292–294.)  To summarize, Montrose 
manufactured the insecticide dichloro-diphenyl-trichloroethane 
(DDT) at its facility in Torrance from 1947 to 1982.  In 1990, the 
United States and the State of California sued Montrose for 
environmental contamination allegedly caused by Montrose’s 
operation of this facility.  Montrose entered into partial consent 
decrees in which it agreed to pay for environmental cleanup.  To 
meet its obligations, Montrose has now expended millions of 
dollars—Montrose represents the total is more than $100 
million—and asserts that its anticipated future liability could 
approach or exceed this amount. 
 
Montrose purchased primary and excess comprehensive 
general liability insurance to cover its operations at the 
Torrance facility from defendant insurers between 1961 and 
1985.  Primary insurance refers to the first layer of coverage, 
whereby “liability attaches immediately upon the happening of 
the occurrence that gives rise to liability.”  (Olympic Ins. Co. v. 
Employers Surplus Lines Ins. Co. (1981) 126 Cal.App.3d 593, 
597.)  Excess insurance, by contrast, “refers to indemnity 
coverage that attaches upon the exhaustion of underlying 
insurance coverage for a claim.”  (County of San Diego v. Ace 
Property & Casualty Ins. Co. (2005) 37 Cal.4th 406, 416, fn. 4.)  
An excess insurer’s coverage obligation begins once a certain 
level of loss or liability is reached; that level is generally referred 
to as the “attachment point” of the excess policy.  (Rest., Liability 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
3 
Insurance, § 39, com. d, p. 338.)  Here, 40 insurers collectively 
issued more than 115 excess policies during the 1961 to 1985 
period, which collectively provide coverage sufficient to 
indemnify Montrose’s anticipated total liability.   
 
Montrose and the insurers, which are the real parties in 
interest here,1 agree for purposes of this dispute that Montrose’s 
                                       
1  
The real party insurers are:  Continental Casualty 
Company and Columbia Casualty Company, joined by AIU 
Insurance Company; Allstate Insurance Company (solely as 
successor in interest to Northbrook Excess and Surplus 
Insurance 
Company); 
American 
Centennial 
Insurance 
Company; American Home Assurance Company; Federal 
Insurance Company; Employers Insurance 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, The Employers Liability Assurance Corporation, Ltd., 
and Employers Surplus Lines Insurance Company); Employers 
Mutual Casualty Company; 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 (as 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 The Manhattan Fire 
 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
4 
primary coverage has been exhausted.  Further, the parties 
have stipulated to the relevant language found in the excess 
policies.2  Specifically, each policy provides that Montrose must 
exhaust the limits of its underlying insurance coverage before 
there will be coverage under the policy.  The policies describe 
the applicable underlying coverage in four main ways: 
 
1.  Some policies contain a schedule of underlying 
insurance listing all of the underlying policies in the same policy 
period by insurer name, policy number, and dollar amount. 
 
2.  Some policies reference a specific dollar amount of 
underlying insurance in the same policy period and a schedule 
of underlying insurance on file with the insurer. 
 
3.  Some policies reference a specific dollar amount of 
underlying insurance in the same policy period and identify one 
or more of the underlying insurers. 
 
4.  Some policies reference a specific dollar amount of 
underlying insurance that corresponds with the combined limits 
of the underlying policies in that policy period. 
                                       
and Marine Insurance Company); Zurich 
International 
(Bermuda), Ltd. 
 
Insurers Travelers Casualty and Surety Company 
(formerly known as Aetna Casualty and Surety Company) and 
The Travelers Indemnity Company opposed Montrose on 
independent grounds and filed a separate answering brief. 
2  
The record does not contain complete copies of every policy 
between Montrose and the insurers.  Instead, the parties have 
identified the terms of these policies that they believe are 
sufficient to resolve this dispute.  The parties agree the various 
policies use different language that all communicates the same 
exhaustion requirement in different ways.  
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
5 
 
In a variety of ways, the excess policies also provide that 
“other insurance” must be exhausted before the excess policy 
can be accessed.  Relevant examples include the following: 
• Some policies provide that they will “indemnify the 
insured for the amount of loss which is in excess of the 
applicable limits of liability of the [scheduled] underlying 
insurance,” and then define “loss” 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.) 
• Some policies state that the insurer is liable for “the 
ultimate net loss in excess of the retained limit” and define 
“retained limit” to mean, among other things, the “total of 
the applicable limits of the underlying policies listed in [a 
schedule] [and] the applicable limits of any other 
underlying insurance collectible by the insured.”  (Italics 
added.) 
• Under a “Loss Payable” provision, one policy provides it 
will pay “any ultimate net loss,” which is separately 
defined as “the sums paid in settlement of losses for which 
the Insured is liable after making deductions for all 
recoveries, salvages and other insurance (other than 
recoveries under the underlying insurance, policies of co-
insurance, or policies specifically in excess hereof).”  (Italics 
added.) 
• Under a “Limits” provision, some policies provide that “the 
insurance afforded under this policy shall apply only after 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
6 
all underlying insurance has been exhausted.”  (Italics 
added.) 
• One policy states that “[i]f other valid and collectible 
insurance with any other insurer is available to the 
Insured covering a loss also covered by this policy, other 
than insurance that is in excess of the insurance afforded 
by this policy, the insurance afforded by this policy shall 
be in excess of and shall not contribute with such other 
insurance.”  (Italics added.) 
 
Montrose and the insurers disagree whether these 
clauses—which we will collectively call “other insurance” 
clauses—require Montrose to exhaust other insurance coverage 
from other policy periods.  This dispute dates to 1990, when 
Montrose first sued its insurers to resolve various coverage 
disputes, but the relevant filing for our purposes occurred in 
2015, when Montrose’s fifth amended complaint asserted a new 
cause of action seeking the following declaration: 
 
“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.” 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
7 
 
The rule Montrose proposes in its amended complaint is a 
rule of “vertical exhaustion” or “elective stacking,” whereby it 
may access any excess policy once it has exhausted other policies 
with lower attachment points in the same policy period.  The 
insurers, in contrast, each of which has issued an excess policy 
to Montrose in one of the triggered policy years, argue for a rule 
of “horizontal exhaustion,” whereby Montrose may access an 
excess policy only after it has exhausted other policies with 
lower attachment points from every policy period in which the 
environmental damage resulting in liability occurred.  The 
parties filed cross-motions for summary adjudication of this 
issue.3 
 
The trial court denied Montrose’s motion and granted the 
insurers’ motion, holding that the excess policies required 
horizontal exhaustion in the context of this multiyear injury.  
The court concluded there is a “ ‘well-established rule that 
horizontal exhaustion should apply in the absence of policy 
language specifically describing and limiting the underlying 
insurance.’ ”  Montrose filed a petition for a writ of mandate, 
                                       
3  
One set of insurers, Travelers Casualty and Surety 
Company and The Travelers Indemnity Company (collectively, 
Travelers), 
opposed 
Montrose’s 
motion 
for 
summary 
adjudication for two independent reasons.  First, Travelers 
argued that Montrose’s requested declaration would entitle 
Montrose to indemnification without actually exhausting the 
relevant underlying insurance, as required by the terms of the 
Travelers policies.  Travelers further argued that California law 
did not apply to their policies.  Because the Court of Appeal 
concluded for other reasons that Montrose was not entitled to 
summary adjudication, it did not address the issues raised by 
Travelers.  We did not grant review of either question, as 
discussed at part II.D., post. 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
8 
which the Court of Appeal summarily denied.  We granted 
Montrose’s petition for review and transferred the case to the 
Court of Appeal with instructions to issue an order to show 
cause why the relief Montrose sought should not be granted. 
 
The Court of Appeal affirmed the trial court’s denial of 
Montrose’s motion for summary adjudication and affirmed in 
part the trial court’s grant of the insurers’ parallel motion.  
(Montrose Chemical Corp. v. Superior Court (2017) 14 
Cal.App.5th 1306, 1321, 1338 (Montrose II).)  The court 
concluded that the plain language of many of the excess policies 
purchased by Montrose provide that they “attach not upon 
exhaustion of lower layer policies within the same policy period, 
but rather upon exhaustion of all available insurance.”  (Id. at 
p. 1327.) 
 
Shortly after the Court of Appeal published its opinion in 
this case, another Court of Appeal disagreed with its reasoning 
in State of California v. Continental Ins. Co. (2017) 15 
Cal.App.5th 1017.  The court in that case determined that 
vertical exhaustion was appropriate given the relevant policy 
language and our case law.  (Id. at pp. 1031–1037.) 
 
We granted review in this case to determine whether 
vertical exhaustion or horizontal exhaustion is required when 
continuous injury occurs over the course of multiple policy 
periods for which an insured purchased multiple layers of excess 
insurance.  Reading the relevant policy language in light of 
background principles of insurance law and considering the 
parties’ reasonable expectations, we conclude that a rule of 
vertical exhaustion is appropriate.  Under that rule, the insured 
has access to any excess policy once it has exhausted other 
directly underlying excess policies with lower attachment 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
9 
points, but an insurer called upon to indemnify the insured’s loss 
may seek reimbursement from other insurers that issued 
policies covering relevant policy periods.4 
II. 
A. 
 
We begin our analysis with a few background insurance 
law principles specific to the continuous or “long-tail” injury at 
issue here, where damage occurs over multiple policy periods.  
(See State of California v. Continental Ins. Co. (2012) 55 Cal.4th 
186, 195–196 (Continental).)  In a much earlier iteration of this 
case, we noted “the settled rule” is 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,” up to 
the policy’s limit.  (Montrose Chemical Corp. v. Admiral Ins. Co. 
(1995) 10 Cal.4th 645, 686, italics added (Montrose I).)  “There 
is no requirement that . . . the conditions giving rise to the 
damage or injury . . . themselves occur within the policy period 
in order for potential liability coverage to arise.”  (Ibid.)  
Extending this logic to the continuous injury context, we held 
that “bodily injury and property damage which is continuous or 
progressively deteriorating throughout several policy periods is 
potentially covered by all policies in effect during those periods.”  
(Id. at p. 689.)  This principle is also known as the “continuous 
injury trigger of coverage.”  (Ibid.) 
                                       
4 
Because the question is not presented here, we do not 
decide when or whether an insured may access excess policies 
before all primary insurance covering all relevant policy periods 
has been exhausted. 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
10 
In Aerojet-General Corp. v. Transport Indemnity Co. 
(1997) 17 Cal.4th 38, 57 (Aerojet), we illustrated the principle 
with an example:  If an insured company discharges a hazardous 
substance that causes property damage in the amount of 
$100,000 each year for a span of 30 years, a $1 million insurance 
policy that is purchased for the first year of that 30-year span 
would be required to pay the insured the full $1 million limit for 
indemnification.  Even though the damage traceable to the 
policy year in which the insurance policy was in effect only 
amounted to $100,000, the insurer is liable for all damages.  As 
we explained, the insurer’s obligation to pay is “triggered if 
specified harm is caused by an included occurrence, so long as 
at least some such harm results within the policy period.”  (Id. 
at p. 56, fn. omitted, citing Montrose I, supra, 10 Cal.4th at 
pp. 669–673.)  “It extends to all specified harm caused by an 
included occurrence, even if some such harm results beyond the 
policy period.”  (Aerojet, at pp. 56–57.)   
This “all sums” rule, as we described it in Aerojet, means 
that “insurers [a]re responsible for defending the insured for all 
claims that involved the triggering damage” in a continuous 
injury case; “as long as the policyholder is insured at some point 
during the continuing damage period, the insurers’ indemnity 
obligations persist until the loss is complete, or terminates.”  
(Continental, supra, 55 Cal.4th at p. 197, citing Aerojet, supra, 
17 Cal.4th at p. 71; Continental, at p. 200 [under all sums 
allocation, insurers must “pay all sums for property damage 
attributable to the [polluted] 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’ ”].)  We adopted this 
rule because, contrary to Aerojet’s stylized example, “[i]t is often 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
11 
‘virtually impossible’ for an insured to prove what specific 
damage occurred during each of the multiple consecutive policy 
periods in a progressive property damage case.”  (Id. at p. 196.)  
“If such evidence were required, an insured who had procured 
insurance coverage for each year during which a long-tail injury 
occurred likely would be unable to recover.”  (Ibid.)  The all sums 
approach, we explained, “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.”  (Id. at p. 200.) 
 
Finally, recognizing that the limits of any one policy may 
be insufficient to cover the entire liability resulting from a 
continuous injury, we concluded in Continental that the insured 
may seek indemnification from every policy that covered a 
portion of the loss, up to the full limits of each policy.  
(Continental, supra, 55 Cal.4th at p. 200.)  This “all-sums-with-
stacking indemnity principle,” we said, “properly incorporates 
the Montrose [I] continuous injury trigger of coverage rule and 
the Aerojet all sums rule, and ‘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.’ ”  (Id. at p. 201.)  “ ‘[T]his approach treats all 
the triggered insurance as though it were purchased in one 
policy period’ ” and recognizes “the uniquely progressive nature 
of long-tail injuries that cause progressive damage throughout 
multiple policy periods.”  (Ibid.)  Importantly, “the insured has 
immediate access to the insurance it purchased.”  (Ibid.)  The 
insurers can then sort out their proportional share through 
actions for equitable contribution or subrogation.  (Id. at p. 200; 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
12 
see Continental Cas. Co. v. Zurich Ins. Co. (1961) 57 Cal.2d 27, 
37.)5 
 
Having adopted an all-sums-with-stacking approach to 
the coverage of long-tail injuries, we are now presented with a 
follow-on question:  In what order may an insured access excess 
policies from different policy periods to cover liability arising 
from long-tail injuries?  To illustrate the parties’ competing 
approaches, consider a hypothetical company that caused 
property damage over three years that resulted in $90 million of 
damage.  Further imagine that in each of these three years, the 
company had purchased primary insurance with a $10 million 
limit and two layers of excess insurance, each providing an 
additional $10 million of coverage: 
 
 
                                       
5 
In a contribution action, an insurer that paid more than 
its share in the initial coverage action can seek reimbursement 
from other insurers that were obligated to indemnify or defend 
the same loss or claim.  (Fireman’s Fund Ins. Co. v. Maryland 
Casualty Co. (1998) 65 Cal.App.4th 1279, 1293.)  The doctrine of 
equitable subrogation allows an insurer to stand in the shoes of 
the insured and recover from third parties that are liable to the 
insured for a loss that the insurer both insured and paid.  (Id. at 
pp. 1291–1292.)  As a general matter, these types of actions 
allow insurers to apportion liability for losses among themselves 
after the insured has been indemnified. 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
13 
 
 
Year 1 
Year 2 
Year 3 
$50 million 
 
 
 
$40 million 
 
 
 
$30 million 
Policy 2A 
Policy 2B 
Policy 2C 
$20 million 
Policy 1A 
Policy 1B 
Policy 1C 
$10 million 
Primary 
Insurance 
Primary 
Insurance 
Primary 
Insurance 
 
 
We are tasked with deciding between two proposed 
methods by which these six excess insurance policies might be 
stacked after the primary insurance has been exhausted to cover 
the $90 million liability in a way that “ ‘treats all the triggered 
insurance as though it were purchased in one policy period.’ ”  
(Continental, supra, 55 Cal.4th at p. 201.)  Under the insurers’ 
proposed rule of horizontal exhaustion, the insured would have 
to exhaust all of its lower layer excess coverage across all 
relevant policy periods before accessing any of its higher layer 
coverage: 
 
 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
14 
 
$90 million 
Policy 2C 
$80 million 
Policy 2B 
$70 million 
Policy 2A 
$60 million 
Policy 1C 
$50 million 
Policy 1B 
$40 million 
Policy 1A 
$30 million 
Primary 
Insurance 
$20 million 
Primary 
Insurance 
$10 million 
Primary 
Insurance 
 
 
Under Montrose’s proposed rule of vertical exhaustion, in 
contrast, an insured would be permitted to access any higher 
layer excess policy once it has exhausted the directly underlying 
excess policy covering the same period: 
 
 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
15 
 
$90 million 
Policy 2C 
$80 million 
Policy 1C 
$70 million 
Policy 2B 
$60 million 
Policy 1B 
$50 million 
Policy 2A 
$40 million 
Policy 1A 
$30 million 
Primary 
Insurance 
$20 million 
Primary 
Insurance 
$10 million 
Primary 
Insurance 
 
 
Which approach applies depends on the terms of the 
parties’ agreement.  We therefore begin by looking, as we must, 
to the language of the insurance policies at issue.  (Minkler v. 
Safeco Ins. Co. of America (2010) 49 Cal.4th 315, 321 (Minkler); 
AIU Ins. Co. v. Superior Court (1990) 51 Cal.3d 807, 822–823.) 
B. 
 
“The principles governing the interpretation of insurance 
policies in California are well settled.  ‘Our goal in construing 
insurance contracts, as with contracts generally, is to give effect 
to the parties’ mutual intentions.  [Citations.]  “If contractual 
language is clear and explicit, it governs.”  [Citations.]  If the 
terms are ambiguous [i.e., susceptible of more than one 
reasonable interpretation], we interpret them to protect “ ‘the 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
16 
objectively 
reasonable 
expectations 
of 
the 
insured.’ ” ’ ”  
(Minkler, supra, 49 Cal.4th at p. 321.)  If these rules do not 
resolve an ambiguity, we may then “ ‘resort to the rule that 
ambiguities are to be resolved against the insurer.’ ”  (Ibid.) 
 
The parties’ dispute centers on the meaning of the “other 
insurance” clauses in the excess insurance policies.  These 
clauses provide, in a variety of ways, that each policy shall be 
excess to other insurance available to the insured, whether or 
not the other insurance is specifically listed in the policy’s 
schedule of underlying insurance.  The insurers argue that these 
clauses call for a rule of horizonal exhaustion because they 
restrict indemnification from any excess policy until the insured 
has exhausted all other available insurance—which, in a case of 
long-tail injury, means every policy with a lower attachment 
point from every policy period triggered by the continuous 
injury. 
 
Although 
the 
insurers’ 
interpretation 
is 
not 
an 
unreasonable one, it is not the only possible interpretation of the 
policy language.6  The “other insurance” clauses at issue clearly 
                                       
6  
Nor, contrary to the insurers’ suggestion, has this 
interpretation already been adopted in California cases.  The 
insurers invoke various cases interpreting “other insurance” 
clauses in other settings, but none addresses the question here:  
whether 
“other 
insurance” 
clauses 
require 
horizontal 
exhaustion of excess insurance policies in cases involving long-
tail injury.  (See, e.g., Legacy Vulcan Corp. v. Superior Court 
(2010) 185 Cal.App.4th 677, 689–690 [addressing defense 
obligations of a policy providing both excess and “umbrella” 
defense coverage]; Peerless Cas. Co. v. Continental Cas. Co. 
(1956) 144 Cal.App.2d 617, 625–626 [excess insurer not required 
to contribute when insurance settlement was prorated across 
 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
17 
require exhaustion of underlying insurance, but none clearly or 
explicitly states that Montrose must exhaust insurance with 
lower attachment points purchased for different policy periods.  
Policies that disclaim coverage for amounts covered by “other 
underlying insurance,” or require exhaustion of “all underlying 
insurance,” for example, could fairly be read to refer only to 
other directly underlying insurance in the same policy period 
that was not specifically identified in the schedule of underlying 
insurance, 
anticipating 
that 
the 
scheduled 
underlying 
insurance may later be replaced or supplemented with different 
policies.   
 
Other formulations require deductions for, in the words of 
one set of representative policies, all “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.)  If this language were read to apply to 
insurance purchased for other policy periods, it could fairly be 
understood to require the exhaustion of every other insurance 
policy at every attachment point—not merely, as the insurers’ 
theory of horizontal exhaustion would have it, excess policies 
from other policy periods that contain lower attachment points.  
The insurers do not advance this expansive reading, however; 
they contend that the reference to “other insurance,” properly 
understood, means “other underlying insurance”—that is, only 
excess insurance with lower attachment points from all relevant 
policy periods.  The insurers do not explain why the reference is 
not properly understood to mean “other directly underlying 
                                       
two primary insurers and at least one primary policy remained 
unexhausted].) 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
18 
insurance”—that is, a requirement that the insured exhaust 
only excess insurance with lower attachment points from the 
same policy period.  This is one clue that the plain language of 
these clauses is not adequate to resolve the dispute in the 
insurers’ favor. 
 
Consideration of the traditional use of “other insurance” 
clauses reinforces our doubts about the insurers’ interpretation.  
As we have previously explained, “ ‘[h]istorically, “other 
insurance” clauses were designed to prevent multiple recoveries 
when more than one policy provided coverage for a particular 
loss.’ ”  (Dart Industries, Inc. v. Commercial Union Ins. Co. 
(2002) 28 Cal.4th 1059, 1079 (Dart).)  They have not generally 
been understood as dictating a particular exhaustion rule for 
policyholders seeking to access successive excess insurance 
policies in cases of long-tail injury. 
 
In Dart, we considered the meaning of an “other 
insurance” clause in a different context.  There, the policyholder 
had acquired successive primary policies covering multiple 
decades and subsequently sought defense and indemnity from 
one of its primary insurers for a continuous injury during that 
time even though the policy provided by that insurer had been 
lost or destroyed.  (Dart, supra, 28 Cal.4th at pp. 1064–1065.)  
The policyholder was able to prove the material terms of the 
policy, but the insurer argued that its contractual obligations 
may have been relieved or reduced by an “other insurance” 
clause in the lost policy, pointing to the other policies purchased 
for the period during which the injury occurred.  (Id. at p. 1078.)  
We rejected this argument, explaining that reliance on an “other 
insurance” clause could not be used to “defeat the insurer’s 
obligations altogether.”  (Id. at p. 1079.)  In other words, the 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
19 
insurer in Dart could not simply invoke the possibility of an 
“other insurance” clause to escape its coverage obligations.  We 
reasoned, in a passage the parties have focused on here:  
“ ‘[A]pportionment 
among 
multiple 
insurers 
must 
be 
distinguished from apportionment between an insurer and 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).’ ”  (Id. at p. 1080, 
quoting Armstrong World Industries, Inc. v. Aetna Casualty & 
Surety Co. (1996) 45 Cal.App.4th 1, 105–106.)  
 
The parties dispute whether Dart meant to set out a 
categorical view of the meaning of “other insurance” clauses in 
cases of continuous injury and whether that view forecloses the 
insurers’ proposed interpretation of the “other insurance” 
clauses in the distinct context we confront here.  Citing Dart, 
Montrose asserts that the “other insurance” clauses are relevant 
to contribution actions between insurers but not to coverage 
actions between insurers and policyholders.  (See State of 
California v. Continental Ins. Co., supra, 15 Cal.App.5th at 
p. 1032.)  We need not rely on any such categorical rule in this 
case, however; it is enough to observe that Dart undermines the 
insurers’ claim that the “other insurance” clauses clearly and 
explicitly call for a rule of horizontal exhaustion.   
 
In rejecting the insurer’s claim in Dart, we emphasized 
that “other insurance” clauses have not traditionally been used 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
20 
to address questions concerning the obligation of successive 
insurers to indemnify policyholders for a continuously 
manifesting injury (a question which, as Dart reminds us, “is a 
separate issue from the obligations of the insurers to each other” 
(Dart, supra, 28 Cal.4th at p. 1080)).  (Id. at p. 1078, fn. 6.)  
Elaborating on the same point, the Restatement explains that 
“other insurance” clauses have generally been used to address 
“[a]llocation questions with respect to overlapping concurrent 
policies.”  (Rest., Liability Insurance, supra, § 40, com. c, p. 345, 
italics added.)  Consistent with this understanding, most courts 
to address the issue have found that “other insurance” clauses 
are not aimed at governing the proper allocation of liability 
among successive insurers in cases of long-tail injury or the 
appropriate sequence in which a policyholder may access its 
insurance across several policy periods.  (Id., § 41, com. j, p. 361; 
see In re Viking Pump, Inc. (2016) 27 N.Y.3d 244, 266 [52 N.E.3d 
1144, 1157] [holding that “other insurance” clauses do not 
mandate horizontal exhaustion under all sums allocation, and 
explaining that “ ‘other insurance’ clauses ‘apply when two or 
more policies provide coverage during the same period, and they 
serve to prevent multiple recoveries from such policies’ . . . .  
[O]ther insurance clauses are not implicated in situations 
involving successive—as opposed to concurrent—insurance 
policies”]; see also Steadfast Insurance Co. v. Greenwich Ins. 
(2019) 385 Wis.2d 213, 228 [922 N.W.2d 71, 79] [“ ‘The accepted 
meaning of “other insurance” provisions does not include 
application to successive insurance policies.’ ”]; Ohio Cas. Ins. 
Co. v. Unigard Ins. Co. (Utah 2012) 268 P.3d 180, 184 [“ ‘[O]ther 
insurance’ provisions do not apply to successive insurers.”]; 
Boston Gas Co. v. Century Indem. Co. (2009) 454 Mass. 337, 361 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
21 
[910 N.E.2d 290, 308] [“ ‘[O]ther insurance’ clauses simply 
reflect a recognition of the many situations in which concurrent, 
not successive, coverage would exist for the same loss.”]; 
Benjamin Moore & Co. v. Aetna Cas. (N.J. 2004) 843 A.2d 1094, 
1101 [“ ‘[O]ther insurance’ clauses, which are provisions 
typically designed to preclude a double recovery when multiple, 
concurrent policies provide coverage for a loss[,] . . . [are] not 
generally applicable in the continuous-trigger context where 
successive rather than concurrent policies [are] at issue.”].)  
Given the generally understood purpose of “other insurance” 
clauses, it is difficult to read the clauses here as a clear and 
explicit direction to adopt a requirement of horizontal 
exhaustion in cases of long-tail injury. 
 
While the “other insurance” clauses do not speak clearly 
to the question before us, other aspects of the insurance policies 
strongly suggest that the exhaustion requirements were meant 
to apply to directly underlying insurance and not to insurance 
purchased for other policy periods.  First and most obviously, 
the excess policies explicitly state their attachment point, 
generally by referencing a specific dollar amount of underlying 
insurance in the same policy period that must be exhausted.  For 
example, certain Fireman’s Fund Insurance Company policies 
provide:  “It is a condition of this policy that the insurance 
afforded under this policy shall apply only after all underlying 
insurance has been exhausted.”  The policies then list the 
“Underlying Insurance Limit of Liability”—for example, 
“$30,000,000 each occurrence $30,000,000 aggregate.”  In other 
words, this policy agrees to indemnify Montrose once it has 
exhausted $30 million of underlying insurance.  But under the 
insurers’ theory of horizontal exhaustion, Montrose would not 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
22 
be permitted to access this policy until it has exhausted $30 
million of underlying insurance for every relevant policy period—
which would add up to substantially more than $30 million.  
Indeed, here, where the continuous injury occurred over the 
course of a quarter century, such a rule would increase the 
operative attachment point for this policy from $30 million to 
upwards of $750 million.  Thus, where aggregate liability 
amounts to approximately $200 million, Montrose would not be 
able to access an insurance policy that, by its terms, kicks in 
after $30 million of underlying insurance is exhausted. 
 
Relatedly, the excess policies regularly include or 
reference schedules of underlying insurance—all for the same 
policy period.  Under Montrose’s reading, these schedules 
provide a presumptively complete list of insurance coverage that 
must be exhausted before the excess policy may be accessed, 
with the “other insurance” clauses serving as a backstop to 
prevent double recovery in the rare circumstance where 
underlying coverage changes after the excess policy is written.  
(See Dart, supra, 28 Cal.4th at p. 1079.)  But under the insurers’ 
rule of horizontal exhaustion, these schedules would represent 
only a fraction—perhaps only a small fraction—of the insurance 
policies that must be exhausted before a given excess policy may 
be accessed.   
 
In sum, the “other insurance” clauses do not clearly specify 
whether a rule of horizontal or vertical exhaustion applies here.  
Read in isolation, the “other insurance” clauses might plausibly 
be read to perform the function the insurers ascribe to them.  
But read in conjunction with the actual language of other 
provisions in the policies, and in light of their historical role of 
governing allocation between overlapping concurrent policies, 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
23 
the insurers’ reading becomes less likely.  Rather, in the absence 
of any more persuasive indication that the parties intended 
otherwise, the policies are most naturally read to mean that 
Montrose may access its excess insurance whenever it has 
exhausted the other directly underlying excess insurance 
policies that were purchased for the same policy period.  
C. 
 
To the extent any of the language of these policies remains 
ambiguous, we resolve these ambiguities to protect “ ‘ “ ‘the 
objectively 
reasonable 
expectations 
of 
the 
insured.’ ” ’ ”  
(Minkler, supra, 49 Cal.4th at p. 321.)  Consideration of the 
parties’ reasonable expectations favors a rule of vertical 
exhaustion rather than horizontal exhaustion. 
 
For starters, applying the horizontal exhaustion rule 
would be far from straightforward.  The insurers describe the 
rule in simple terms:  as a matter of traveling across “layers” of 
stacked “blocks” of excess insurance coverage before the insured 
may travel upwards.  But this depiction suggests a degree of 
standardization across policies that does not exist.  The policies 
Montrose purchased come in all shapes and sizes, each covering 
different periods of time, providing different levels of coverage, 
and setting forth distinct exclusions, terms, and conditions.  
Given all of these variations across the relevant dimensions, 
how would a rule of horizonal exhaustion apply?  If one were to 
stack the excess policies on a graph based on their coverage 
limits or attachment points, the first layer of excess insurance 
in 1984, for example, would appear to reach as high as the 13th 
layer of excess coverage in 1974.  To which horizontal layer does 
the 1984 policy belong?  The policies do not say.  Nor does 
anything in the text of these policies tell us how an “other 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
24 
insurance” clause in a policy from one period ought to apply to a 
policy from another period that contains both a lower 
attachment point and a higher coverage limit.  The policies’ 
silence on these basic, foundational questions tends to 
undermine the idea the parties expected such a rule to apply. 
 
But perhaps more importantly, because the exclusions, 
terms, and conditions may vary from one policy to another, a 
rule of horizontal exhaustion would create significant practical 
obstacles to securing indemnification.  As the Court of Appeal 
stated in State of California v. Continental Ins. Co., supra, 15 
Cal.App.5th at page 1033, “if a lower-layer insurer for a different 
policy period happened to claim that some exclusion in its policy 
applied, a court could not determine whether Continental’s 
policies were triggered without first determining that exclusion 
claim.”  Such a rule would put the insured to the considerable 
expense of establishing a right to coverage under the definitions, 
terms, conditions, and exclusions from policies in every policy 
period triggered by the continuous injury.  Coverage under less 
restrictive policies would be delayed until more restrictive policy 
terms are adjudicated.  In sum, “[h]orizontal exhaustion would 
create as many layers of additional litigation as there are layers 
of policies.”  (Westerport Ins. Corp. v. Appleton Papers Inc. 
(Wis.Ct.App. 2010) 787 N.W.2d 894, 918.)  What is more, 
requiring a policyholder to litigate the terms and conditions of 
all policies with lower attachment points in every policy period 
before accessing policies with higher attachment points would 
effectively 
increase 
the 
attachment 
point—thereby 
undermining the policyholder’s reasonable expectation that 
coverage would be triggered upon the exhaustion of the amount 
listed as the policy’s stated attachment point.  Objectively 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
25 
speaking, the parties could not have intended to require the 
insured to surmount all these hurdles before the insured may 
access the excess insurance it has paid for. 
 
The insurers counter that the rule of horizontal 
exhaustion is logically compelled by our adoption of an all-sums-
with-stacking approach to liability for long-tail injuries.  They 
argue that if the insured is to have access to all policies across 
all relevant policy periods, it only makes sense that the insured 
must seek indemnification based on its excess coverage across 
all relevant policy periods; to do otherwise, the insurers assert, 
would “artificially break[]” the long-tail injury into distinct 
periods, contrary to our holding in Continental.  (Continental, 
supra, 55 Cal.4th at p. 201.)  But the insurers’ conclusion does 
not follow.  A rule of vertical exhaustion does not restrict the 
insured from accessing excess coverage from other policy periods 
if the terms and conditions are otherwise met; it merely relieves 
the insured of the obligation of establishing whether all of the 
applicable terms and conditions at any given “layer” of excess 
coverage are met before it accesses the next “layer” of coverage.  
There is no evident inconsistency between an all sums approach 
and one that avoids placing this burden on the insured, with its 
associated delays, before the insured may access its excess 
insurance. 
 
But if horizontal exhaustion imposes a heavy burden on 
the insured, the insurers claim that vertical exhaustion is 
“totally 
unfair” 
to 
them 
because 
“decades’ 
worth 
of 
environmental damage [could] fall on the shoulders of 
disfavored insurers who happened to provide excess insurance 
. . . during that single unlucky year or two.”  This argument is 
not different in kind from arguments we have already 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
26 
considered and rejected in adopting the all-sums-with-stacking 
approach to the coverage of long-tail injuries.  (See, e.g., 
Continental, supra, 55 Cal.4th at pp. 199–200; id. at pp. 201–
202.)  What we have said in prior cases applies here as well:  
There is no evident unfairness to insurers when their insureds 
incur liabilities triggering indemnity coverage under the 
negotiated policy contract.7  Just as the all-sums-with-stacking 
approach allows the insured “immediate access to the insurance 
it purchased,” so, too, does vertical exhaustion in a continuous 
injury case.  (Continental, at p. 201.) 
 
Equally to the point, nothing about the rule of vertical 
exhaustion requires a single insurer to shoulder the burden of 
indemnification alone.  As we explained in the context of 
primary insurance, “the obligation of successive primary 
insurers to cover a continuously manifesting injury is a separate 
issue from the obligations of the insurers to each other.”  (Dart, 
supra, 28 Cal.4th at p. 1080.)  Even though a rule of vertical 
exhaustion permits Montrose to access excess insurance from 
any given policy period, provided the directly underlying 
insurance has been exhausted, insurers may seek contribution 
from other excess insurers also liable to the insured.  The 
exhaustion rule does not alter the usual rules of equitable 
contribution between insurers.  An insurer required to provide 
excess coverage for a long-tail injury may lessen its burden by 
seeking reimbursement from other insurers that issued policies 
during the relevant period.  Once again, the critical difference 
                                       
7  
Whether losses may be partially allocated to the insured 
for policy periods in which the insured chose to self-insure is a 
question not presented here. 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
27 
between a rule of vertical exhaustion and horizontal exhaustion 
thus is not whether a single disfavored excess insurer will be 
made to carry a disproportionate burden of indemnification, but 
instead whether the administrative task of spreading the loss 
among insurers is one that must be borne by the insurer instead 
of the insured.  There is no obvious unfairness to insurers from 
a rule that requires them to bear this administrative burden. 
 
The insurers lean heavily on Community Redevelopment 
Agency v. Aetna Casualty & Surety Co. (1996) 50 Cal.App.4th 
329, but that case addresses a meaningfully different scenario 
and thus offers no real lessons for resolving the question now 
before us.  In Community Redevelopment, a primary insurer 
sought contribution from an excess insurer for defense costs on 
behalf of the insured in a case involving continuous loss.  To 
resolve the conflict, the court applied what it termed a 
“horizontal exhaustion rule”; under that rule, the court held, an 
excess insurer in a continuous injury case is not required “to 
‘drop down’ and provide a defense to a common insured before 
the liability limits of all primary insurers on the risk have been 
exhausted.”  (Id. at p. 332.)  In adopting that rule, the court 
explained:  “Absent a provision in the excess policy specifically 
describing and limiting the underlying insurance, a horizontal 
exhaustion rule should be applied in continuous loss cases 
because it is most consistent with the principles enunciated in 
Montrose [I, supra, 10 Cal.4th 645]. . . .  Under the principle of 
horizontal exhaustion, all of the primary policies must exhaust 
before any excess will have coverage exposure.”  (Community 
Redevelopment, at p. 340.) 
 
This case differs from Community Redevelopment in 
fundamental 
respects. 
 
This 
case, 
unlike 
Community 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
28 
Redevelopment, is not a contribution action between primary 
and excess insurers; it is, rather, a coverage dispute between 
excess insurers and their insured.  Regardless of whether 
Community Redevelopment was correct to apply a rule of 
horizontal exhaustion in that distinct context—a question not 
presently before us—we are unpersuaded that the reasoning of 
Montrose I requires us to apply a rule of horizontal exhaustion 
that would limit Montrose’s ability to access the excess 
insurance coverage it has paid for. 
 
In sum, we conclude that in a case involving continuous 
injury, where all primary insurance has been exhausted, the 
policy language at issue here permits the insured to access any 
excess policy for indemnification during a triggered policy period 
once the directly underlying excess insurance has been 
exhausted.  Parties to insurance contracts are, of course, free to 
write their policies differently to establish 
alternative 
exhaustion requirements or coverage allocation rules if they so 
wish.  (See Continental, supra, 55 Cal.4th at p. 202.) 
D. 
 
As noted earlier, Travelers opposes Montrose’s motion for 
summary adjudication on two independent grounds.  First, 
Travelers argues that Montrose’s requested declaration, which 
would permit Montrose to “seek indemnification” from an excess 
policy upon establishing that “its liabilities are sufficient to 
exhaust the underlying policy(ies) in the same policy period,” is 
directly contrary to the terms of the Travelers policies, which 
require actual exhaustion before a policyholder may access 
excess coverage.  Second, Travelers argues that its policies with 
Montrose must be construed under Connecticut or New York 
law, rather than California law as assumed by Montrose’s 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
29 
petition, given Montrose’s principal place of business at the time 
the Travelers policies were issued.  The lower court did not reach 
either of these issues because it determined for other reasons 
that Montrose is not entitled to summary adjudication.  
(Montrose II, supra, 14 Cal.App.5th at p. 1336, fn. 9.) 
 
These arguments are not properly before us.  We granted 
Montrose’s petition to determine whether Montrose may seek 
coverage from its excess policies under a rule of vertical 
exhaustion rather than horizontal exhaustion.  The choice 
between these two rules does not alter any of the remaining 
prerequisites Montrose must satisfy to obtain indemnification, 
including actual exhaustion of directly underlying insurance, 
according to the specific terms of its excess policies.  And because 
the lower courts have not addressed the competing claims about 
choice of law, we decline to resolve the matter in the first 
instance.  (See Guz v. Bechtel National Inc. (2000) 24 Cal.4th 
317, 348.)  Whether California law governs the construction of 
Montrose’s policies with Travelers is a question for the Court of 
Appeal on remand. 
III. 
 
California law permits Montrose to seek indemnification 
under any excess policy once Montrose has exhausted the 
underlying excess policies in the same policy period.  Montrose 
is not required to exhaust excess insurance at lower levels for 
all periods triggered by continuous injury before obtaining  
 
 
MONTROSE CHEMICAL CORPORATION OF CALIFORNIA  
v. SUPERIOR COURT 
Opinion of the Court by Kruger, J. 
 
30 
coverage from higher level excess insurance in any period.  We 
reverse the judgment of the Court of Appeal and remand for 
further proceedings consistent with this opinion. 
 
 
 
 
 
 
KRUGER, J. 
 
We Concur: 
CANTIL-SAKAUYE, C. J. 
LIU, J. 
CUÉLLAR, J. 
GROBAN, J. 
ELIA, J.* 
BROWN, J.** 
                                       
* 
Associate Justice of the Court of Appeal, Sixth Appellate 
District, assigned by the Chief Justice pursuant to article VI, 
section 6 of the California Constitution. 
** 
Associate Justice of the Court of Appeal, First Appellate 
District, Division Four, assigned by the Chief Justice pursuant 
to article VI, section 6 of the California Constitution. 
 
 
See next page for addresses and telephone numbers for counsel who argued in Supreme Court. 
 
Name of Opinion Montrose Chemical Corp. v. Superior Court 
__________________________________________________________________________________ 
 
Unpublished Opinion 
Original Appeal 
Original Proceeding  
Review Granted XXX 14 Cal.App.5th 1306 
Rehearing Granted 
 
__________________________________________________________________________________ 
 
Opinion No. S244737 
Date Filed:  April 6, 2020  
__________________________________________________________________________________ 
 
Court:  Superior 
County:  Los Angeles 
Judge:  Elihu Berle 
 
__________________________________________________________________________________ 
 
Counsel: 
 
Latham & Watkins, Brook B. Roberts, John M. Wilson and Drew T. Gardiner for Petitioner. 
 
Morgan Lewis & Bockius, Michel Y. Horton, Jeffrey S. Raskin, Thomas M. Peterson, Paul A. Zevnik 
and David S. Cox for ITT LLC and Santa Fe Braun, Inc., as Amici Curiae on behalf of Petitioner. 
 
No appearance for Respondent. 
 
Gibson, Dunn & Crutcher, Theodore J. Boutrous, Jr., Julian W. Poon, Jeremy S. Smith and Madeleine F. 
McKenna for Real Parties in Interest Continental Casualty Company, Columbia Casualty Company, 
American Centennial Insurance Company and Lamorak Insurance Company. 
 
 
Sinnott, Puebla, Campagne & Curet, Kenneth H. Sumner and Lindsey A. Morgan for Real Parties in 
Interest AIU Insurance Company, American Home Assurance Company, Granite State Insurance 
Company, Landmark Insurance Company, Lexington Insurance Company, National Union Fire Insurance 
Company of Pittsburgh, PA, and New Hampshire Insurance Company. 
 
Sinnott, Puebla, Campagne & Curet, Randolph P. Sinnott, Mary E. Gregory; 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 Party in Interest Munich Reinsurance America, Inc. 
 
Selman & Breitman, Ilya A. Kosten, Kelsey C. Start; Barbanel & Treuer and Alan H. Barbanel 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 Parties 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 and MT. McKinley Insurance Company. 
 
Chamberlin & Keaster, Chamberlin Keaster & Brockman, Kirk C. Chamberlin, Michael 
Denlinger and Kevin J. Schettig for Real Party in Interest Providence Washington Insurance Company. 
 
Tressler, Linda Bondi Morrison and Ryan B. Luther for Real Party in Interest Allstate Insurance Company. 
 
Archer Norris, Andrew J. King, GailAnn Y. Stargardter; Tressler and Charles R. Diaz for Real Parties in 
Interest Fireman's Fund Insurance Company and National Surety Corporation. 
 
Lewis, Brisbois, Bisgaard & Smith, Jordon E. Harriman, Shannon L. Santos; Budd Larner and Michael J. 
Balch for Real Parties in Interest General Reinsurance Corporation and North Star Reinsurance 
Corporation. 
 
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 & Drury and Andrew McCloskey for Real Party in Interest 
Westport Insurance Corporation. 
  
Simpson Thacher & Bartlett, Peter R. Jordon, Andrew T. Frankel, Deborah Lynn Stein and Tyler Z. 
Bernstein for Real Parties in Interest Travelers Casualty and Surety Company and The Travelers Indemnity 
Company. 
 
Covington & Burling, David B. Goodwin, Reynold L. Siemens, Jeffrey A. Kiburtz and Heather W. Habes 
for United Policyholders as Amicus Curiae on behalf of Petitioner. 
 
 
 
 
 
 
 
 
 
 
 
 
 
Counsel who argued in Supreme Court (not intended for publication with opinion): 
 
John Wilson 
Latham & Watkins LLP 
12670 High Bluff Drive 
San Diego, CA 92130 
(858) 523-5400 
 
Theodore J. Boutrous, Jr. 
Gibson, Dunn & Crutcher, LLP 
333 South Grand Avenue 
Los Angeles, CA 90071 
(213) 229-7500