California Chamber of Commerce v. Cert

FOR PUBLICATION

UNITED STATES COURT OF APPEALS
FOR THE NINTH CIRCUIT

CALIFORNIA CHAMBER OF No. 21-15745
COMMERCE,
Plaintiff-Appellee, D.C. No.
2:19-cv-02019-
v. KJM-JDP

COUNCIL FOR EDUCATION AND
RESEARCH ON TOXICS, a California OPINION
public benefit corporation,
Intervenor-Defendant-Appellant.

Appeal from the United States District Court
for the Eastern District of California
Kimberly J. Mueller, Chief District Judge, Presiding

Argued and Submitted January 12, 2022
San Francisco, California

Filed March 17, 2022

Before: Ronald M. Gould, Mark J. Bennett, and
Ryan D. Nelson, Circuit Judges.

Opinion by Judge Bennett
2 CAL. CHAMBER OF COM. V. CERT

SUMMARY *

Civil Rights

In an action brought pursuant to 42 U.S.C. § 1983, the
panel affirmed the district court’s order granting California
Chamber of Commerce’s motion for a preliminary
injunction that prohibited the Attorney General and his
officers, employees, or agents, and all those in privity or
acting in concert with those entities or individuals, including
private enforcers from filing or prosecuting new lawsuits to
enforce the Proposition 65 warning requirement for cancer
as applied to acrylamide in food and beverage products.

Proposition 65 or, Prop. 65, provides that “[n]o person in
the course of doing business shall knowingly and
intentionally expose any individual to a chemical known to
the state to cause cancer . . . without first giving clear and
reasonable warning to such individual, except as provided in
Section 25249.10.” Cal. Health & Safety Code § 25249.6.

California Chamber of Commerce (“CalChamber”) filed
suit for declaratory and injunctive relief against the Attorney
General of California, seeking to halt acrylamide litigation
brought under Prop. 65. It sought to vindicate its members’
First Amendment rights to not be compelled to place false
and misleading acrylamide warnings on their food products.
The Council for Education and Research on Toxics
(“CERT”) intervened as a defendant and argued that, as a
private enforcer of Prop. 65, an injunction would impose an

*
This summary constitutes no part of the opinion of the court. It
has been prepared by court staff for the convenience of the reader.
 CAL. CHAMBER OF COM. V. CERT 3

unconstitutional prior restraint on its First Amendment
rights. CERT is the sole appellant challenging the
preliminary injunction on appeal.

The panel held that intervenor CERT had standing
because it suffered an invasion of a legally protected interest
when the district court enjoined it from filing Prop. 65
lawsuits as to acrylamide in food and beverage products.

Applying Zauderer v. Office of Disciplinary Counsel,
471 U.S. 626 (1985), the panel addressed whether
CalChamber was likely to succeed on the merits of its
compelled speech First Amendment claim. The panel held
that given the robust disagreement by reputable scientific
sources over whether acrylamide in food causes cancer in
humans, the district court did not abuse its discretion in
concluding that the warning was controversial. The district
court similarly did not abuse its discretion in finding the
warning was misleading. Finally, the record supported the
district court’s finding that Prop. 65’s enforcement regime
created a heavy litigation burden on manufacturers who use
alternative warnings rather than the approved safe harbor
warning set forth in California’s Health and Safety
Regulations. Because California and CERT did not meet
their burden to show the warning requirement was lawful
under Zauderer, the district court did not abuse its discretion
when it concluded that CalChamber was likely to succeed on
the merits of its First Amendment claim.

The panel rejected CERT’s argument that the district
court’s injunction was a prior restraint that violated its First
Amendment right to petition. The serious constitutional
issue raised by CalChamber gave the district court sufficient
reason to enjoin Prop. 65 acrylamide litigation until the case
was finally decided on the merits. The panel held that a
4 CAL. CHAMBER OF COM. V. CERT

preliminary injunction against likely unconstitutional
litigation is not an unconstitutional or otherwise
impermissible prior restraint.

The panel concluded that there was no abuse of
discretion in the district court’s analysis of the remaining
preliminary injunction factors. The district court correctly
found that CalChambers had established irreparable harm,
which is relatively easy to establish in a First Amendment
case. The panel further found that the scope of the injunction
was not impermissible; that the balance of hardships
weighed in CalChamber’s favor; and that the injunction
would be in the public interest.

COUNSEL

Raphael Metzger (argued) and Scott Brust, Metzger Law
Group, A Professional Law Corporation, Long Beach,
California, for Intervenor-Defendant-Appellant.

Trenton H. Norris (argued), S. Zachary Fayne, and David M.
Barnes, Arnold & Porter Kaye Scholer LLP, San Francisco,
California, for Plaintiff-Appellee.

Jeffrey B. Margulies and Andy Guo, Norton Rose Fulbright
US LLP, Los Angeles, California, for Amici Curiae of
Consumer Brands Association, American Bakers
Association, American Beverage Association, California
Grain and Feed Association, California League of Food
Producers, California Grocers Association, California
Retailers Association, California Seed Association, National
Confectioners Association, Plant California Alliance, and
SNAC International.
 CAL. CHAMBER OF COM. V. CERT 5

Rob Bonta, Attorney General of California; Edward H.
Ochoa, Senior Assistant Attorney General; Laura J.
Zuckerman, Supervising Deputy Attorney General; Megan
K. Hey and Rafael J. Hurtado, Deputy Attorneys General;
Office of the California Attorney General, Los Angeles,
California; for Amicus Curiae Rob Bonta.

OPINION

BENNETT, Circuit Judge:

California Chamber of Commerce (“CalChamber”) filed
suit for declaratory and injunctive relief against the Attorney
General of California, seeking to halt acrylamide litigation
brought under California’s Safe Drinking Water and Toxic
Enforcement Act of 1986, better known as Proposition 65 or
Prop. 65. 1 CalChamber argued that Prop. 65’s warning
requirement violates the First Amendment of the U.S.
Constitution on its face and as applied to acrylamide in food
products. The district court granted CalChamber’s motion
for a preliminary injunction, prohibiting “the Attorney
General and his officers, employees, or agents, and all those
in privity or acting in concert with those entities or
individuals, including private enforcers” from filing or
prosecuting “new lawsuit[s] to enforce the Proposition 65

1
In its First Amended complaint, CalChamber named only the
Attorney General as a defendant and sought to “enjoin [the Attorney
General] and those in privity with and acting in concert with [him] from
enforcing in the future a requirement to provide a false, misleading, and
highly controversial cancer warning for food and beverage products . . .
that contain the chemical acrylamide.” CalChamber claimed that those
in privity and acting in concert with the Attorney General included
“private enforcers of Proposition 65 under Cal. Health & Safety Code
§ 25249.7(d).”
6 CAL. CHAMBER OF COM. V. CERT

warning requirement for cancer as applied to acrylamide in
food and beverage products.” Council for Education and
Research on Toxics (“CERT”) intervened as a defendant 2
and is the sole appellant challenging the preliminary
injunction. We have jurisdiction under 28 U.S.C.
§ 1292(a)(1), and we affirm. 3

I. FACTS AND PROCEDURAL BACKGROUND

Prop. 65 provides that “[n]o person in the course of doing
business shall knowingly and intentionally expose any
individual to a chemical known to the state to cause cancer
. . . without first giving clear and reasonable warning to such
individual, except as provided in Section 25249.10.” Cal.
Health & Safety Code § 25249.6. One exception under
Section 25249.10 applies to those who “can show that the
exposure poses no significant risk assuming lifetime
exposure at the level in question for substances known to the
state to cause cancer.” Id. § 25249.10(c). This is known as
the “No Significant Risk Level.” See Nat’l Ass’n of Wheat
Growers v. Becerra, 468 F. Supp. 3d 1247, 1254 (E.D. Cal.
2020).

A chemical is “known to the state to cause cancer” if it
meets one of three statutory criteria: (1) the state’s qualified
experts believe “it has been clearly shown through
scientifically valid testing according to generally accepted

2
CERT moved to intervene nine days after the lawsuit was filed.
Both CalChamber and the Attorney General filed statements of non-
opposition.
3
Noerr-Pennington immunity is at issue in our concurrently filed
opinion in B&G Foods North America, Inc. v. Kim Embry, No. 20-
16971. Though CERT raised Noerr-Pennington immunity below, it
abandoned that argument on appeal.
 CAL. CHAMBER OF COM. V. CERT 7

principles to cause cancer”; (2) “a body considered to be
authoritative by such experts has formally identified it as
causing cancer”; or (3) “an agency of the state or federal
government has formally required it to be labeled or
identified as causing cancer.” Cal. Health & Safety Code
§ 25249.8(b). The California Office of Environmental
Health Hazard Assessment (“OEHHA”) “is the lead agency
designated by the Governor to implement and enforce
Proposition 65.” Cal. Chamber of Com. v. Brown, 126 Cal.
Rptr. 3d 214, 219 n.5 (Ct. App. 2011). In its initially
published list of chemicals known to cause cancer, OEHHA
“listed only chemicals that had been identified as
carcinogens . . . based on human epidemiological studies. It
did not include chemicals identified as carcinogens . . . based
on animal studies.” Id. at 219 (citation omitted). Today, a
“chemical agent must be listed even if it is known to be
carcinogenic . . . only in animals.” Am. Chemistry Council
v. Off. of Envt’l Health Hazard Assessment, 270 Cal. Rptr.
3d 379, 402 (Ct. App. 2020).

OEHHA’s regulations provide that a cancer warning for
foods is “clear and reasonable” if it states: “WARNING:
Consuming this product can expose you to [name
of chemical], which is known to the State of California to
cause cancer. For more information go to
www.P65Warnings.ca.gov/food.” See Cal. Code Regs. tit.
27, § 25607.2(a)(1), (2). This is known as the “safe harbor”
warning. A party that fails to provide such a warning or
otherwise establish an exception may be enjoined, Cal.
Health & Safety Code § 25249.7(a), and “is liable for a civil
penalty not to exceed two thousand five hundred dollars
($2,500) per day for each violation,” id. § 25249.7(b)(1).

Prop. 65 enforcement actions “may be brought by the
Attorney General in the name of the people of the State of
8 CAL. CHAMBER OF COM. V. CERT

California, by a district attorney,” by a city attorney or city
prosecutor, or “by a person in the public interest.” Id.
§ 25249.7(c), (d). Before suing, the person acting in the
public interest must provide a sixty-day notice of the alleged
violation to the Attorney General, other local prosecutors
with jurisdiction, and the alleged violator. Id.
§ 25249.7(d)(1). The private enforcer can only bring suit if
“[n]either the Attorney General, a district attorney, a city
attorney, nor a prosecutor has commenced and is diligently
prosecuting an action against the violation.” Id.
§ 25249.7(d)(2).

OEHHA added acrylamide to the Prop. 65 list in 1990
“because studies showed it produced cancer in laboratory
rats and mice.” 4 OEHHA, Acrylamide, https://oehha.ca.gov/
proposition-65/general-info/acrylamide (last visited Mar. 3,
2022). The EPA found that acrylamide was a “likely”
human carcinogen, and the International Agency for
Research on Cancer classified it as “probably carcinogenic
to humans.” According to the FDA, acrylamide “is a
chemical that can form in some foods during high-
temperature cooking processes, such as frying, roasting, and
baking” and was first detected in foods in 2002. But the
National Cancer Institute stated that “a large number of
epidemiologic studies . . . have found no consistent evidence
that dietary acrylamide exposure is associated with the risk
of any type of cancer.” The American Cancer Society stated
that studies “suggest that dietary acrylamide isn’t likely to
be related to risk for most common types of cancer.” And
the FDA has stated that “warning labels based on the
presence of acrylamide in food might be misleading.”

4
Toxicological studies have shown that tumors are observed in
rodents only when they are exposed to acrylamide at approximately 500
times the average daily amount consumed by Americans.
 CAL. CHAMBER OF COM. V. CERT 9

Between 2015 and October 2020, private enforcers have sent
almost 1,000 notices of alleged acrylamide violations to the
Attorney General.

CalChamber is a nonprofit business association with
over 13,000 members, many of whom sell or produce food
products that contain acrylamide. It filed its complaint to
vindicate its members’ First Amendment right to not be
compelled to place false and misleading acrylamide
warnings on their food products. CalChamber’s preliminary
injunction motion sought to prohibit parties from “filing
and/or prosecuting new lawsuits to enforce the Proposition
65 warning requirement for cancer as applied to acrylamide
in food and beverage products.” CalChamber submitted
expert declarations stating that there is no consistent or
reliable evidence that acrylamide increases the risk of any
type of cancer in humans, that the toxicological studies
related to experimental animals are not relevant to humans
at real-world levels of exposure, and that California
consumers understood Prop. 65’s safe harbor warning “to
convey the message that eating [food with acrylamide]
increases their risk of getting cancer.”

In opposition, the Attorney General submitted a
declaration from an expert who stated that evidence shows
that acrylamide is a human carcinogen. Intervenor CERT
also opposed the motion, arguing an injunction would
impose an unconstitutional prior restraint on its First
Amendment rights. 5

5
Nothing in any of CERT’s district court filings asserted or
suggested that CERT was asserting the rights of any other private
enforcers.
10 CAL. CHAMBER OF COM. V. CERT

The district court granted the preliminary injunction.
Under the injunction:

While this action is pending and until a
further order of this court, no person may file
or prosecute a new lawsuit to enforce the
Proposition 65 warning requirement for
cancer as applied to acrylamide in food and
beverage products. This injunction applies to
the requirement that any “person in the
course of doing business” provide a “clear
and reasonable warning” for cancer before
“expos[ing] any individual to” acrylamide in
food and beverage products under California
Health & Safety Code § 25249.6. It applies
to the Attorney General and his officers,
employees, or agents, and all those in privity
or acting in concert with those entities or
individuals, including private enforcers under
section 25249.7(d) of the California Health
and Safety Code.

This order does not alter any existing
consent decrees, settlements, or other
agreements related to Proposition 65 warning
requirements.

Cal. Chamber of Com. v. Becerra, 529 F. Supp. 3d 1099,
1123 (E.D. Cal. 2021) (alteration in original). The district
court found that CalChamber was likely to succeed on the
merits because neither the State nor CERT had shown that
the Prop. 65 cancer warning for acrylamide in food is
“purely factual and uncontroversial.” The district court also
rejected CERT’s prior restraint argument.
 CAL. CHAMBER OF COM. V. CERT 11

CERT appealed the preliminary injunction order, but the
Attorney General did not. A divided motions panel of this
court 6 granted in part CERT’s motion for an emergency stay
of the preliminary injunction pending appeal. The majority
found that “[e]ven if a court could enjoin lawsuits that
infringe on a defendant’s established First Amendment right
against compelled speech, no court has made a final
determination that a Proposition 65 warning is, in fact,
unconstitutional with respect to acrylamide exposure.” The
motions panel also stated that the “breadth of the
injunction”—prohibiting Prop. 65 lawsuits “with regard to
acrylamide exposure by any private actor, including those
who are not parties to the underlying action”—“exacerbates
the concerns underlying the prior restraint doctrine.” The
motions panel stayed the preliminary injunction only to the
extent it barred private enforcers, including CERT, from
filing or prosecuting Prop. 65 lawsuits. Another motions
panel later denied CalChamber’s motion to dismiss CERT’s
appeal for lack of standing.

II. STANDARD OF REVIEW

This court reviews “the district court’s decision to grant
or deny a preliminary injunction for abuse of discretion. . . .
The district court’s interpretation of the underlying legal
principles, however, is subject to de novo review and a
district court abuses its discretion when it makes an error of
law.” Sw. Voter Registration Educ. Project v. Shelley, 344

6
Dissenting, Judge Forrest stated that CERT did not contend that it
intended to file any enforcement lawsuits, that CERT had filed no
enforcement suits since CalChamber filed the litigation, and that CERT
could still send demand letters. Judge Forrest believed CalChamber
“raised serious questions regarding whether the warning required by
Proposition 65 as [it] relates to acrylamide is permissible compelled
commercial speech.”
12 CAL. CHAMBER OF COM. V. CERT

F.3d 914, 918 (9th Cir. 2003) (en banc) (per curiam) (citation
omitted).

“A district court abuses its discretion if it rests its
decision ‘on an erroneous legal standard or on clearly
erroneous factual findings.’” Am. Beverage Ass’n v. City &
County of San Francisco, 916 F.3d 749, 754 (9th Cir. 2019)
(en banc) (quoting United States v. Schiff, 379 F.3d 621, 625
(9th Cir. 2004)). “A district court’s decision is based on an
erroneous legal standard if: ‘(1) the court did not employ the
appropriate legal standards that govern the issuance of a
preliminary injunction; or (2) in applying the appropriate
standards, the court misapprehended the law with respect to
the underlying issues in the litigation.’” Negrete v. Allianz
Life Ins. Co. of N. Am., 523 F.3d 1091, 1096 (9th Cir. 2008)
(quoting Clear Channel Outdoor Inc. v. City of Los Angeles,
340 F.3d 810, 813 (9th Cir. 2003), abrogated on other
grounds by Winter v. Nat. Res. Def. Council, Inc., 555 U.S. 7
(2008)).

“In the context of a trial court’s factual findings, as
applied to legal rules, to determine whether a district court
has abused its discretion, the first step . . . is to determine de
novo whether the trial court identified the correct legal rule
to apply to the relief requested.” Enyart v. Nat’l Conf. of Bar
Exam’rs, Inc., 630 F.3d 1153, 1159 (9th Cir. 2011) (cleaned
up). “If the trial court identified the correct legal rule, the
second step is to determine whether the trial court’s
application of the correct legal standard was (1) illogical,
(2) implausible, or (3) without support in inferences that may
be drawn from the facts in the record.” Id. (cleaned up).

“We review the scope of an injunction for abuse of
discretion.” Nat’l Wildlife Fed’n v. Nat’l Marine Fisheries
Serv., 886 F.3d 803, 823 (9th Cir. 2018).
 CAL. CHAMBER OF COM. V. CERT 13

III. DISCUSSION

A. Standing

We first address the jurisdictional challenge raised by
CalChamber. Notwithstanding that CERT intervened, that
CalChamber sought to enjoin CERT, and that the
preliminary injunction obtained by CalChamber does enjoin
CERT, CalChamber argues that CERT lacks standing to
appeal. CalChamber claims that the injunction might not
affect CERT because CERT “does not have any pending 60-
day notices concerning acrylamide in food on which it could
file suit.” 7 CalChamber therefore contends that CERT “does
not have Article III standing and its appeal cannot proceed.”
CERT argues that because the district court enjoined “CERT
and all other private enforcers from filing Proposition 65
cases regarding acrylamide in food, CERT ha[s] standing to
appeal.” We agree with CERT.

“[T]o appeal a decision that the primary party does not
challenge, an intervenor must independently demonstrate
standing.” Va. House of Delegates v. Bethune-Hill, 139
S. Ct. 1945, 1951 (2019). “Standing under Article III of the
Constitution requires that an injury be concrete,
particularized, and actual or imminent; fairly traceable to the
challenged action; and redressable by a favorable ruling.”
Monsanto Co. v. Geertson Seed Farms, 561 U.S. 139, 149
(2010). The Supreme Court has “repeatedly reiterated that
threatened injury must be certainly impending to constitute

7
CalChamber also argues that it would be absurd for the Attorney
General and other elected officials to not be able to enforce Prop. 65
while private enforcers could. But this result would flow from the
Attorney General’s decision not to appeal, not from any lack of injury to
CERT. Moreover, it was CalChamber that sought to enjoin both the
Attorney General and private enforcers like CERT.
14 CAL. CHAMBER OF COM. V. CERT

injury in fact, and that allegations of possible future injury
are not sufficient.” Clapper v. Amnesty Int’l USA, 568 U.S.
398, 409 (2013) (cleaned up). As the Court held in
TransUnion LLC v. Ramirez, 141 S. Ct. 2190 (2021),
“Congress may not authorize plaintiffs who have not
suffered concrete harms to sue in federal court simply to
enforce general compliance with regulatory law.” Id. at
2207 n.3. The same principle applies to an intervenor
seeking to appeal. Va. House of Delegates, 139 S. Ct. at
1950–51.

We first note that CERT recently filed a Prop. 65
enforcement action against manufacturers and retailers of air
fryers, alleging air fryers “generate extremely high levels of
acrylamide to which Californians are exposed.” CERT does
not contend that air fryers are “food and beverage products,”
and stated at oral argument that its litigation against air fryer
manufacturers would not have been barred by the injunction.
CERT acknowledged that the defendants in that litigation,
however, might contend that because air fryers create
acrylamide in foods, the litigation would have been barred
by the preliminary injunction, absent the stay. CalChamber
stated at oral argument that the pending case faces the
question whether air fryers are food and beverage products,
and that the defendants in that case might argue that they are.

CERT did not contend below that it specifically intended
to file any Prop. 65 lawsuits or pre-litigation notices about
acrylamide in food or beverage products. Nor did it make
such a claim in opposition to the motion to dismiss the
appeal for lack of standing. Nonetheless, we look to CERT’s
long history of bringing suits against manufacturers of food
and beverage products, CERT’s statement that it has
“devote[d] [its] efforts to initiating new Proposition 65
matters regarding acrylamide,” and CERT’s very recent
 CAL. CHAMBER OF COM. V. CERT 15

litigation against air fryers, as significant evidence of
CERT’s concrete interest in bringing Prop. 65 litigation
related to acrylamide in food and beverage products. We
also note that CalChamber has not cited, nor have we found,
any case in which an enjoined party was denied, on standing
grounds, the right to appeal the injunction.

We hold that CERT suffered “an invasion of a legally
protected interest,” Lujan v. Defs. of Wildlife, 504 U.S. 555,
560 (1992), when the district court enjoined it from filing
Prop. 65 lawsuits as to acrylamide in food and beverage
products. We find that CERT has suffered a concrete,
particularized, and actual injury. Cf. Elrod v. Burns, 427
U.S. 347, 373 (1976) (“The loss of First Amendment
freedoms, for even minimal periods of time, unquestionably
constitutes irreparable injury.”). The injury is directly
traceable to the preliminary injunction and redressable by a
reversal of that injunction. We thus conclude that CERT has
standing, and we proceed to the merits of CalChamber’s and
CERT’s arguments on appeal.

B. Preliminary Injunction

For a court to grant a preliminary injunction, a plaintiff
“must establish [1] that he is likely to succeed on the merits,
[2] that he is likely to suffer irreparable harm in the absence
of preliminary relief, [3] that the balance of equities tips in
his favor, and [4] that an injunction is in the public interest.”
Winter, 555 U.S. at 20.

1. Likelihood of Success on the Merits

a. Compelled Speech

The district court applied the three-factor test from
Zauderer v. Office of Disciplinary Counsel, 471 U.S. 626
16 CAL. CHAMBER OF COM. V. CERT

(1985), to decide whether “the compelled warning
(1) requires the disclosure of purely factual and
uncontroversial information only, (2) is justified and not
unduly burdensome, and (3) is reasonably related to a
substantial government interest.” The district court’s first
two factors combine the “three inquiries” that comprise
“[t]he Zauderer test, as applied in [National Institute of
Family & Life Advocates v. Becerra (“NIFLA”), 138 S. Ct.
2361 (2018)]”: “whether the notice is (1) purely factual,
(2) noncontroversial, and (3) not unjustified or unduly
burdensome.” Am. Beverage, 916 F.3d at 756. 8 In CTIA-
The Wireless Ass’n v. City of Berkeley (“CTIA-II”), 928 F.3d
832 (9th Cir. 2019), we joined our sister circuits in holding
that “the Zauderer exception for compelled speech applies
even in circumstances where the disclosure does not protect
against deceptive speech.” Id. at 843. We held that “the
governmental interest in furthering public health and safety
is sufficient under Zauderer so long as it is substantial.” Id.
at 844. The third factor considered by the district court here
aligns with our holding in CTIA-II. The district court thus
initially used the correct framework for determining whether
Prop. 65’s warning requirement was a constitutionally
permissible compelled disclosure.

The district court then found that the Prop. 65 acrylamide
warning did not pass constitutional muster. “Courts asked
to issue preliminary injunctions based on First Amendment
grounds face an inherent tension: the moving party bears the
burden of showing likely success on the merits . . . and yet
within that merits determination the government bears the
burden of justifying its speech-restrictive law.” Thalheimer
v. City of San Diego, 645 F.3d 1109, 1115 (9th Cir. 2011),

8
The inquiries or criteria need not be addressed in any particular
order. Am. Beverage, 916 F.3d at 756.
 CAL. CHAMBER OF COM. V. CERT 17

overruled on other grounds by Bd. of Trs. of Glazing Health
& Welfare Tr. v. Chambers, 941 F.3d 1195, 1199 (9th Cir.
2019) (en banc). “Therefore, in the First Amendment
context, the moving party bears the initial burden of making
a colorable claim that its First Amendment rights have been
infringed, or are threatened with infringement, at which
point the burden shifts to the government to justify the
restriction” on speech. Id. at 1116.

CalChamber bore the initial burden to show a colorable
claim. As the district court found, “[t]he parties agree[d]
Proposition 65 compels commercial speech.” Thus, the
court shifted its inquiry to assessing whether California
could justify the compelled disclosure under Zauderer. The
district court found that “[1] the State has not shown that the
safe-harbor acrylamide warning is purely factual and
uncontroversial, and [2] Proposition 65’s enforcement
system can impose a heavy litigation burden on those who
use alternative warnings.” 9 The court found that “the
warning implies incorrectly that acrylamide is an additive or
ingredient,” and “is likely misleading.” The court also
referenced the consumer survey submitted by CalChamber
that shows how those “who read the safe harbor warning will
probably believe that eating the food increases their personal
risk of cancer.” The court acknowledged that some studies
would “support such an inference,” but also noted “dozens
of epidemiological studies have failed to tie human cancer to
a diet of food containing acrylamide.” Thus, it found “the
safe harbor warning is controversial because it elevates one

9
As noted, the safe-harbor warning reads: “Consuming this product
can expose you to [acrylamide], which is . . . known to the State of
California to cause cancer. For more information go to
www.P65Warnings.ca.gov/food.” Cal. Code Regs. tit. 27,
§ 25607.2(a)(2).
18 CAL. CHAMBER OF COM. V. CERT

side of a legitimately unresolved scientific debate about
whether eating foods and drinks containing acrylamide
increases the risk of cancer.”

The record supports the district court’s findings. First,
the district court found that the safe harbor warning is
controversial because of the scientific debate over whether
acrylamide in food causes cancer in humans. In 2019, the
American Cancer Society stated that “dietary acrylamide
isn’t likely to be related to risk for most common types of
cancer.” According to the National Cancer Institute, while
“[s]tudies in rodent models have found that acrylamide
exposure increases the risk for several types of cancer[,] . . .
a large number of epidemiologic studies . . . in humans have
found no consistent evidence that dietary acrylamide
exposure is associated with the risk of any type of cancer.”
One epidemiologist who reviewed 56 studies concluded that
“there is no consistent or reliable evidence to support a
finding that dietary exposure to acrylamide increases the risk
of any type of cancer in humans.” In her publication, the
researcher noted that the “epidemiologic studies . . . have
failed to detect an increased risk of cancer, and they raise
serious doubt regarding the validity of extrapolating from
rodent studies suggestive of multiorgan effects to humans.”
These opinions weigh against the conclusions of three
organizations: the International Agency for Research on
Cancer classifies acrylamide as “probably carcinogenic to
humans,” the U.S. National Toxicology Program classifies
acrylamide as “reasonably anticipated to be a human
carcinogen,” and the EPA classifies acrylamide as “likely to
be carcinogenic to humans.” Given this robust disagreement
 CAL. CHAMBER OF COM. V. CERT 19

by reputable scientific sources, the court did not abuse its
discretion in concluding that the warning is controversial. 10

The court similarly did not abuse its discretion in finding
the warning is misleading. Scientific debate aside, Prop.
65’s meaning of the word “known” is not conveyed in the
warning. 11 The district court stated: “Statements are not
necessarily factual and uncontroversial just because they are
technically true.” See CTIA-II, 928 F.3d at 847 (“[A]
statement may be literally true but nonetheless misleading
and, in that sense, untrue.”). Under Prop. 65, a “known”
carcinogen carries a complex legal meaning that consumers
would not glean from the warning without context. 12 Thus,
use of the word “known” is misleading—as the FDA
acknowledged the warning might be. Even the State of
California has stipulated that it “does not know that
acrylamide causes cancer in humans, and is not required to
make any finding to that effect in order to list the chemical
under Proposition 65.” As the consumer survey showed,

10
We do not try to offer a general definition for “controversial” in
the Zauderer context. However controversial is defined, the acrylamide
Prop. 65 warning easily meets the definition because of the scientific
debate.
11
As noted above, the word “known” has a specialized meaning
under Prop. 65, see Cal. Health & Safety Code § 25249.8(b), and
OEHHA added acrylamide to the Prop. 65 list in 1990 “because studies
showed it produced cancer in laboratory rats and mice.”
12
This interpretation of the “factual” requirement can also be
understood as a corollary of the threshold requirement stated in
Zauderer. While the First Amendment allows states and the federal
government to bar others from disseminating false, deceptive, or
misleading commercial speech, 471 U.S. at 638, the First Amendment
also bars the government from compelling others to disseminate false,
deceptive, or misleading commercial disclosures.
20 CAL. CHAMBER OF COM. V. CERT

when consumers read “known to the State of California to
cause cancer” on the packaging of a food or beverage
product, they would believe “that such products pose a risk
of cancer in humans.” But acrylamide “must be listed [as
known to the state to cause cancer] even [though] it is known
to be carcinogenic . . . only in animals.” Am. Chemistry
Council, 270 Cal. Rptr. 3d at 402. A reasonable person
might think that they would consume a product that
California knows will increase their risk for cancer. Such a
consumer would be misled by the warning because the State
of California does not know if acrylamide causes cancer in
humans. The district court did not abuse its discretion when
it concluded the warning is misleading.

Finally, the record supports the district court’s finding
that Prop. 65’s enforcement regime creates a heavy litigation
burden on manufacturers who use alternative warnings. The
district court agreed with CalChamber that “only the safe
harbor warning is actually useable in practice.” The court
found that Prop. 65 “does not permit businesses to add
information to the required warning at their discretion, and
thus prevents them from explaining their views on the true
dangers of acrylamide in food.” Upon receipt of a notice of
violation, CalChamber argues, a business must
“communicate to consumers a disparaging health warning
about food containing acrylamide that is unsupported by
science, or face the significant risk of an enforcement action
under Proposition 65.” The former damages their
“reputation and goodwill” with misleading information, and
the latter bears a risk of “civil penalties of up to $2,500 per
violation per day.” If the business chooses to defend itself
in the action, it bears the burden of proof to show the
acrylamide levels in their products have a low enough risk
of causing cancer that they do not need a warning. See Cal.
Health & Safety Code § 25249.10(c) (requiring defendants
 CAL. CHAMBER OF COM. V. CERT 21

to prove that the exposure to acrylamide “poses no
significant risk assuming lifetime exposure at the level in
question”). Proving the acrylamide level is lower than the
No Significant Risk Level requires expensive testing and
costly expert testimony if the case proceeds to trial.
“[S]maller businesses . . . often cannot afford” these costs
and “have decided to provide a Proposition 65 cancer
warning for their acrylamide-containing food products, even
though they believe that such a warning is unfounded, to
avoid the risk of Proposition 65 litigation.” Thus, in context,
the compelled disclosure appears unduly burdensome, and
the district court did not abuse its discretion in so finding.

Our circuit has established a clear legal framework for
analyzing the constitutionality of a compelled commercial
disclosure requirement, which the district court dutifully
followed. Because California and CERT did not meet their
burden to show the warning requirement was lawful under
Zauderer, the district court did not abuse its discretion when
it concluded that CalChamber was likely to succeed on the
merits of its First Amendment claim.

The district court assumed without deciding that it was
also necessary to apply the heightened standard of review
under Central Hudson Gas & Electric Corp. v. Public
Service Commission, 447 U.S. 557 (1980). 13 Theoretically,
even if a compelled disclosure failed the Zauderer test
because, for example, it was controversial, the government
could get a “second bite at the apple” by showing that even
if controversial, the compelled speech passed Central
Hudson’s intermediate scrutiny hurdle. The State made this

13
At least one other district court has done the same, finding our
precedent unclear on whether applying the heightened analysis was
necessary. See Wheat Growers, 468 F. Supp. 3d at 1257, 1264.
22 CAL. CHAMBER OF COM. V. CERT

argument below. But CERT has not made this argument on
appeal, nor has CERT even cited Zauderer or Central
Hudson in its briefs. Thus, we need not reach this argument.
Indep. Towers of Wash. v. Washington, 350 F.3d 925, 929–
30 (9th Cir. 2003). 14

b. Prior Restraint

CERT (which, as noted, does not even discuss Zauderer)
argues the injunction is a prior restraint that violates its First
Amendment right to petition. The district court found the
“illegal objective” of any Prop. 65 lawsuit prevented CERT
from making a successful prior restraint claim. 15 Though the
prior restraint doctrine does apply to enjoined lawsuits, we
conclude that the district court’s finding at the preliminary
injunction stage that Prop. 65 acrylamide in food lawsuits
are likely unconstitutional prevents CERT from claiming the
doctrine’s protection.

The Supreme Court has held that “enjoining a lawsuit
could be characterized as a prior restraint.” BE & K Constr.
Co. v. NLRB, 536 U.S. 516, 530 (2002). But courts may
enjoin a lawsuit with “an objective that is illegal” without

14
We note, though, that in CTIA-II we stated: “Five years after
Central Hudson, the Court held that Central Hudson’s intermediate
scrutiny test does not apply to compelled, as distinct from restricted or
prohibited, commercial speech.” 928 F.3d at 842. We also note,
however, that no court appears to have ever directly held that the
government can never compel factually accurate but “controversial”
speech, no matter the government interest, and no matter how
compelling its reasons. We leave that question for another day.
15
In discussing “illegal objective,” the court referenced the potential
that CalChamber would succeed on the merits as problematic for the
petition clause claim because “private enforcement actions targeting
acrylamide would run head-on into a constitutional prohibition.”
 CAL. CHAMBER OF COM. V. CERT 23

violating the Petition Clause. Bill Johnson’s Rests., Inc. v.
NLRB, 461 U.S. 731, 737 n.5 (1983); see also Small v.
Operative Plasterers’ and Cement Masons’ Int’l Ass’n Loc.
200, 611 F.3d 483, 492 (9th Cir. 2010). 16

CERT argues that the district court could not enjoin
Prop. 65 litigation on the basis that it had an illegal objective
until after the court made a final determination on the merits
of CalChamber’s claim. But CERT cited no binding
precedent supporting its claim that the “falsity” of the
compelled speech must be proven at trial, and thus by
definition before a preliminary injunction can issue. And the
cases cited by CERT are distinguishable.

CERT cited a district court case that stated: “A
preliminary injunction is not ideal for resolving the actual
truth or falsity of Defendants’ speech, particularly where the
merits of the matter is already pending in another court.”
Gold Coast Search Partners LLC v. Career Partners, Inc.,
No. 19-cv-03059-EMC, 2019 WL 4305540, at *5 (N.D. Cal.
Sept. 11, 2019). But that court found only that enjoining the
defendants from “stating or claiming that Plaintiffs are
prohibited from conducting their business or that they are
violating any agreement with Defendants” or “stating or
implying that Plaintiffs are bound by the Employment

16
CERT argues that its Prop. 65 lawsuits may not be enjoined
because CERT is not “‘subjectively motivated by an unlawful purpose,’
[BE & K Constr. Co., 536 U.S. at 531], so as to have an ‘illegal objective’
undeserving of First Amendment protection.” But CalChamber need not
allege or prove the subjective motive of Prop. 65 private enforcers. Suits
that have “an objective that is illegal under federal law” may be enjoined
without proving subjective intent. Bill Johnson’s, 461 U.S. at 737 n.5;
Small, 611 F.3d at 492.
24 CAL. CHAMBER OF COM. V. CERT

Agreement” would be an improper prior restraint on speech.
Id. at *4–5. No similar speech is barred here—only lawsuits.

CERT also cites Balboa Island Village Inn, Inc. v.
Lemen, 156 P.3d 339 (Cal. 2007), claiming the California
Supreme Court “held that an injunction that enjoins speech
prior to a determination on the merits is impermissible.” But
the case had nothing to do with enjoining prospective
lawsuits “prior to a determination” on the First Amendment
merits; it involved a bar and restaurant owner seeking to
enjoin a neighbor from interfering with its business by
repeating statements that a court had already found
defamatory. Id. at 341. The California Supreme Court
ultimately determined that the trial court’s permanent
injunction was “overly broad, but that defendant’s right to
free speech would not be infringed by a properly limited
injunction prohibiting defendant from repeating statements
about plaintiff that were determined at trial to be
defamatory.” Id.

CalChamber, on the other hand, offers examples of
preliminary injunctions against litigation to support its
position that enjoining future lawsuits does not constitute an
unlawful prior restraint on CERT’s right to petition. See
County of Orange v. Air Cal., 799 F.2d 535, 537 (9th Cir.
1986); Wood v. Santa Barbara Chamber of Com., Inc., 705
F.2d 1515, 1523 (9th Cir. 1983). The district court also
pointed to other contexts in which federal courts enjoin
prospective state court litigation. 17

17
The district court cited cases as well as federal statutes, such as
the All Writs Act and the Anti-Injunction Act, which show that enjoining
prospective lawsuits does not per se violate the First Amendment.
 CAL. CHAMBER OF COM. V. CERT 25

We agree with CalChamber and the district court. The
serious constitutional issue raised by CalChamber gave the
district court sufficient reason to enjoin Prop. 65 acrylamide
litigation until the case was finally decided on the merits.
The court’s analysis of CalChamber’s First Amendment
claim was an “adequate determination that [such Prop. 65
acrylamide litigation] is unprotected by the First
Amendment.” Pittsburgh Press Co. v. Pittsburgh Comm’n
on Human Rels., 413 U.S. 376, 390 (1973). 18 Thus, we hold
that the preliminary injunction against likely
unconstitutional litigation is not an unconstitutional or
otherwise impermissible prior restraint.

2. Remaining Preliminary Injunction Factors

We conclude there was no abuse of discretion in the
court’s analysis of the remaining preliminary injunction
factors. “Irreparable harm is relatively easy to establish in a
First Amendment case.” CTIA-II, 928 F.3d at 851. The
plaintiff “need only demonstrate the existence of a colorable
First Amendment claim.” Brown v. Cal. Dep’t of Transp.,
321 F.3d 1217, 1225 (9th Cir. 2003) (cleaned up). As we
held above, the district court correctly found that
CalChamber did so.

The district court reviewed the final two factors of the
preliminary injunction test together, weighing the State’s
and private enforcers’ interest in enforcing Prop. 65 against
CalChamber’s members’ First Amendment rights. “[I]t is
always in the public interest to prevent the violation of a
party’s constitutional rights.” Am. Beverage, 916 F.3d at

18
The Court in Pittsburgh Press did not define the parameters of an
“adequate determination.” 413 U.S. at 390. Such adequacy would, of
course, turn on the law and facts in individual cases.
26 CAL. CHAMBER OF COM. V. CERT

758 (quoting Melendres v. Arpaio, 695 F.3d 990, 1002 (9th
Cir. 2012)). The district court noted that the “injunction
requested here is also quite narrow,” allowing “CERT and
other private enforcers [to] send demand letters and notices
of violations,” “litigate existing claims and pursue appeals,”
“pursue public relations campaigns,” “fund research,” and
“buy advertisements.” 19 Though we do not agree with the
“quite narrow” description, the scope of the injunction
speaks for itself, and is not impermissible.

For these reasons, the court found that the balance of
equities tipped in CalChamber’s favor, and that the
injunction would be in the public interest. These findings
were not an abuse of discretion, especially as this court has
“consistently recognized the significant public interest in
upholding First Amendment principles.” Doe v. Harris, 772
F.3d 563, 583 (9th Cir. 2014) (quoting Sammartano v. First
Jud. Dist. Ct., 303 F.3d 959, 974 (9th Cir. 2002), abrogated
on other grounds by Winter, 555 U.S. 7).

C. Scope of the Injunction

CERT argues for the first time in its reply brief that the
injunction was overly broad because CERT and the Attorney
General are not in privity with one another. While we are
unsure if we understand CERT’s argument, which is
forfeited because it is raised for the first time in the reply
brief, we have “discretion to review an issue not raised by
appellant . . . when it is raised in the appellee’s brief.” In re
Riverside-Linden Inv. Co., 945 F.2d 320, 324 (9th Cir.
1991). Given that CalChamber argues that because the

19
CERT argued for the first time on appeal that the notices of
violations are effectively enjoined. This argument is waived. See In re
Mercury Interactive Corp. Sec. Litig., 618 F.3d 988, 992 (9th Cir. 2010).
 CAL. CHAMBER OF COM. V. CERT 27

Attorney General and private enforcers bring Prop. 65
claims in the public interest, private enforcers are “in
privity” with one another and with the Attorney General, we
exercise our discretion to reach only whether the injunction
is overly broad as to CERT. 20

Federal Rule of Civil Procedure 65(d)(2) allows district
courts to enjoin not just the parties and their affiliates, but
also others who are “in active concert or participation” with
them. The Supreme Court has interpreted this language to
allow injunctions to bind not only defendants but also people
“identified with them in interest, in ‘privity’ with them,
represented by them or subject to their control.” Golden
State Bottling Co. v. NLRB, 414 U.S. 168, 179 (1973)
(quoting Regal Knitwear Co. v. NLRB, 324 U.S. 9, 14
(1945)). CalChamber argues that this group includes
“private enforcers who are not parties to this action.” 21

20
We do not reach whether the injunction here is overly broad
against other possible private enforcers. CERT intervened to protect its
own interests and did not purport to speak for other private enforcers.
Because CERT has not asserted the rights or interests of anyone but
itself, its standing is limited to its own interests. We therefore discuss
only whether the injunction was overly broad as to CERT. We express
no view on the merits of whether the injunction was overbroad as it
applies or purports to apply to other private enforcers who were not
named as defendants and who did not intervene.
21
“In general, . . . privity involves a person so identified in interest
with another that he represents the same legal right.” Zaragosa v.
Craven, 202 P.2d 73, 75 (Cal. 1949) (en banc) (quotation marks
omitted). “Generally, to be held liable in contempt, it is necessary that a
non-party respondent must either abet the defendant or must be legally
identified with him. Those not identified with a party, but in active
concert or participation with him, are bound only with actual notice.”
NLRB v. Sequoia Dist. Council of Carpenters, AFL-CIO, 568 F.2d 628,
633 (9th Cir. 1977) (cleaned up).
28 CAL. CHAMBER OF COM. V. CERT

Whether or not this is so, as an intervenor-defendant,
CERT is in a different position from other private enforcers
who are not parties to the case. CERT stated in its motion to
intervene that its interests cannot be adequately represented
by the Attorney General because their interests are adverse.
CERT acknowledged that “as an intervenor, CERT has all of
the same rights and obligations as [those] of a named
defendant.” This includes the duty to be bound by the
district court’s injunction order. See United States v.
Oregon, 657 F.2d 1009, 1014 (9th Cir. 1981) (“Intervenors
under Fed. R. Civ. P. 24(a)(2) . . . enter the suit with the
status of original parties and are fully bound by all future
court orders.”). We concluded at the outset that CERT has
standing to appeal the injunction as a private enforcer,
including because CERT has filed acrylamide lawsuits in the
past and has discussed wanting to file them in the future. As
an intervenor under Fed. R. Civ. P. 24(a), CERT brought
itself into “active concert” and “participation” with the
Attorney General in the context of this litigation. It would
defy logic to now hold that the injunction as applied to
CERT as a private enforcer is overly broad.

IV. CONCLUSION

For all these reasons, the district court did not abuse its
discretion in granting the preliminary injunction. 22

AFFIRMED.

22
We also find no abuse of discretion in the court’s evidentiary
hearing proceedings or its consideration of expert testimony.