1

Filed 4/8/22 (unmodified opn. attached)

CERTIFIED FOR PUBLICATION

IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA

FIRST APPELLATE DISTRICT

DIVISION TWO

LARRY LEE,

Plaintiff and Appellant,

v.

AMAZON.COM, INC.,

Defendant and Respondent.

 A158275

 (Alameda County

 Super. Ct. No. RG14738130)

ORDER MODIFYING OPINION 

AND DENYING REHEARING 

[NO CHANGE IN JUDGMENT

THE COURT:

It is ordered that the opinion filed herein on March 11, 2022, be 

modified as follows:

1. On page 4, second line of first full paragraph, delete the words 

“purchased from Amazon.”

2. On page 4, at the end of the first full paragraph, add the following 

new final sentence: 

The Monsepa sample tested was purchased from 

aztopselstore.com and appears to be the same as the Monsepa 

product available from Amazon; the other four samples tested

were from products purchased from Amazon.

3. On page 11, first and second lines of last partial paragraph, delete 

the word “the” before “product page” and replace it with “Amazon’s,” delete 

the word “the” before “Monsepa,” and delete the words “Lee had tested.” 

These lines should read: 
2

Steinberg was shown a customer comment on Amazon’s product 

page for Monsepa cream saying the news had reported on

January 9, . . .

4. On page 12, second line of second partial paragraph, after “health 

risks from,” delete the words “chemical exposures,” and replace with 

“exposure to chemicals including mercury,”

5. On page 12, delete everything after the first sentence of footnote 15 

and replace it with the following:

He had taught part of a course on risk assessment at San Diego 

State University School of Public Health for about 20 years, 

worked with governmental committees on developing and 

defining methods to assess health risks, and performed more 

than 200 Proposition 65 risk assessments, of which more than 50 

involved metals, more than 50 involved chemicals listed as 

reproductive or developmental toxicants, and “[a]lmost all” had a 

component of “generalizing data to the population of the products 

that we used.” Sheehan had experience evaluating mercury 

exposure in the contexts of site risk assessment, waste disposal,

and a project involving removal of gas pressure regulators from 

homes.

6. On page 18, delete footnote 16, and on page 28, delete footnote 19, 

which will require renumbering of all subsequent footnotes.

7. On page 28, first line of first full paragraph, delete the word “five” 

and replace with “four.”

8. On page 28, second line of first full paragraph, after the words “Web 

site” add the following: “, as well as a fifth such product that appears to be 

available for sale on the Web site,” The first two lines should read: 

Given the undisputed evidence that samples of four skinlightening products purchased on Amazon’s Web site, as 

well as a fifth such product that appears to be available 

for sale on the Web site, contained high levels of mercury as . . . 

9. On page 80, second line of second full paragraph of “DISPOSITION” 

section, add the word “four” before “products.”
3

10. On page 80, at the end of the second full paragraph of the

“DISPOSITION” section, add the following new final sentence: 

As to the fifth product tested for this case, the trial court shall 

determine whether the Monsepa product available on Amazon’s 

Web site was in fact the same product as the one tested.

11. On page 80, after the second full paragraph of the “DISPOSITION” 

section, add the following new third paragraph:

If any violations of Proposition 65 are established, the court shall 

determine the appropriate remedy in accordance with section

25249.7.

There is no change in the judgment. The petitions for rehearing are

denied.

Dated: __________________ _________________________

Richman, Acting P.J.
4

Trial Court: Alameda County Superior Court

Trial Judge: Hon. Robert McGuiness

Attorney for Plaintiff and Appellant Law Office of Jonathan Weissglass

Larry Lee: Jonathan Weissglass

Greenfire Law

Rachel S. Doughty

Jessica L. Blome

Attorneys for Amicus Curiae on behalf Rob Bonta

of Plaintiff and Appellant: Attorney General of California

Dennis A. Ragen

Roxanne Carter

Deputy Attorneys General

Attorneys for Amicus Curiae Danielle R. Fugere

As you Sow on behalf of Plaintiff Chelsea J. Linsley

Appellant:

Attorneys for Amicus Curiae Altshuler Berzon

Center For Food Safety on behalf Barbara J. Chisholm

of Plaintiff and Appellant: P. Casey Pitts

Attorneys for Amici Curiae Black Environmental Law Clinic

Women for Wellness and the Mercury Mills Legal Clinic at Stanford Law School

Policy Project/Tides Center on behalf Deborah A. Sivas

of Plaintiff and Appellant: Molly Loughney Melius

Attorneys for Defendant Doll Amir & Eley

and Respondent Amazon.com, Inc.: Gregory L. Doll

Brett H. Oberst

Jamie O. Kendall

Lloyd Vu

Attorneys for Amicus Curiae Law Office of Fred. J. Hiestand

The Civil Justice Association of Fred J. Hiestand

California on behalf of Defendant

and Respondent:
1

Filed 3/11/22 (unmodified opinion)

CERTIFIED FOR PUBLICATION

IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA

FIRST APPELLATE DISTRICT

DIVISION TWO

LARRY LEE,

Plaintiff and Appellant,

v.

AMAZON.COM, INC.,

Defendant and Respondent.

 A158275

 (Alameda County

 Super. Ct. No. RG14738130)

Under legislation enacted as Proposition 65 in 1986, businesses are 

prohibited from knowingly and intentionally exposing any individual to 

certain chemicals without first providing a warning. Lee seeks to hold 

Amazon.com, Inc. (Amazon) accountable for offering on its Web site, without 

warnings, certain skin-lightening face creams sold by third parties and 

alleged to contain mercury. The trial court concluded that Amazon is 

immune from liability under the federal Communications Decency Act (CDA) 

and also that Lee failed to establish several elements of his case under 

Proposition 65. 

Lee maintains Amazon is not protected by the CDA and the trial court 

erred in its view of the evidence required to establish the alleged statutory 

violations.
2

We agree with Lee and, therefore, will reverse and remand for further 

proceedings.1

BACKGROUND

California’s Safe Drinking Water and Toxic Enforcement Act of 1986 

(Act) (Health & Saf. Code, § 25249.5 et seq.), adopted by voter initiative in 

1986 and commonly known as Proposition 65, provides, “No person in the 

course of doing business shall knowingly and intentionally expose any 

individual to a chemical known to the state to cause cancer or reproductive 

toxicity without first giving clear and reasonable warning to such individual, 

except as provided in Section 25249.10.” (Health & Saf. Code, § 25249.6.) 

Mercury and mercury compounds were listed by the state as reproductive 

toxins under Proposition 65 in 1990. (Cal. Code. Regs., tit. 27,2 § 27001, 

subd. (c); see Health & Saf. Code, § 25249.8.)3 

1 The Attorney General filed an amicus brief in support of Lee pursuant 

California Rules of Court, rule 8.200(c)(7). Exercising his authority to 

represent the public interest, the Attorney General explains he has a “special 

interest in the proper interpretation and enforcement of” Proposition 65 as 

the “public official with statewide authority to enforce” the Safe Drinking 

Water and Toxic Enforcement Act of 1986 and “the only public official with 

authority to review and comment on settlements entered into by private 

enforcers under Proposition 65.” 

Additionally, we granted applications to file amicus briefs from several 

nonprofit organizations whose missions relate to the subject matter of this 

case. We have received amicus briefs on behalf of Lee from As You Sow and 

Center for Food Safety, Black Women for Wellness and the Mercury Policy 

Project/Tides Center, and on behalf of Amazon from the Civil Justice 

Association of California.

2 Further references to “Regulations” are to title 27 of the California 

Code of Regulations except as otherwise specified (e.g., Regs., § 25102).

3 Under California law, a discarded substance is “hazardous waste” if it 

contains 20 milligrams per kilogram, 20 parts per million (ppm) or more of 
3

Cosmetics containing one ppm (0.0001 percent) or more of mercury are 

prohibited under federal law. (21 U.S.C. § 331(a)–(c); 21 C.F.R.

§ 700.13(d)(2)(i).)4 According to the FDA, “[t]he toxicity of mercury 

compounds is extensively documented in scientific literature. . . . Mercury is 

absorbed from topical application and is accumulated in the body, giving rise 

to numerous adverse effects. . . . [C]hronic use of mercury-containing skinbleaching preparations has resulted in the accumulation of mercury in the 

body and the occurrence of severe reactions.” (21 C.F.R. § 700.13(b).)

The present case concerns four brands of face creams advertised as 

skin-lightening or skin-whitening products: Faiza, Face Fresh, Monsepa, and 

Meiyong. 

Lee’s second amended complaint listed 27 products offered for sale on 

Amazon’s Web site under these brand names, identified by individual product 

name or description and “Amazon Standard Identification Number” or 

mercury. (Cal. Code Regs., tit. 22 §§ 66261.2, subd. (a), 66261.20, subd. (a), 

66261.24, subd. (a)(2)(A).)

4 Federal law prohibits “[t]he introduction or delivery for introduction 

into interstate commerce of any . . . cosmetic that is adulterated or 

misbranded,” the “adulteration or misbranding of any . . . cosmetic in 

interstate commerce” and the “receipt in interstate commerce of any . . . 

cosmetic that is adulterated or misbranded, and the delivery or proffered 

delivery thereof for pay or otherwise.” (21 U.S.C. § 331(a)-(c).) The Food and 

Drug Administration (FDA) regards “any cosmetic containing mercury” as 

“adulterated” unless it contains “no more than a trace amount of mercury and 

such trace amount is unavoidable under conditions of good manufacturing 

practice and is less than 1 ppm (0.0001 percent), calculated as the metal” 

(21 C.F.R § 700.13(d)(2)(i)) or it is “intended for use only in the area of the 

eye, it contains no more than 65 ppm (0.0065 percent) of mercury, calculated 

as the metal, as a preservative, and there is no effective and safe 

nonmercurial substitute preservative available for use in such cosmetic.” 

(21 C.F.R. § 700.13(d)(2)(ii).)
4

“ASIN.”5 His pretrial brief subsequently reduced the list of products at issue

to 11, identified by ASIN and name or description: Three by Faiza, one by 

Face Fresh, one by Monsepa, and six by Meiyong.6

Lee had laboratory tests performed on samples of these products 

purchased from Amazon, which found 15,000 ppm mercury in a sample of 

Monsepa Express Peeling cream (ASIN B0030K8GJY) tested in 2017, 9,600 

ppm of mercury in a sample of Faiza Beauty cream (ASIN B00WORM8R0) 

tested in 2016, 5,600 ppm of mercury, in a sample of Face Fresh Beauty 

cream (ASIN B00ZP38YQY) tested in 2015, 21,000 ppm of mercury in a 

sample of Meiyong Seaweed Super Whitening cream (ASIN B00CVJKBDE) 

tested in January 2015, and 2,000 ppm of mercury in another sample of 

Meiyong Seaweed Super Whitening cream (ASIN B008XRYQUM) tested in 

September 2015.

Several samples of Monsepa creams (not purchased from Amazon) had 

previously been tested for California agencies: Tests performed for the 

5 The ASIN is an internal code assigned by Amazon to each unique

product listed on the Web site. 

6 The 11 products were: “Original Faiza Beauty Cream Whitening 

Cream Anti Pimple Cream Freckle Cream” (ASIN B00WORM8R0), “Faiza 

Beauty Cream/To Remove Freckles & Dark Spots” (ASIN B00V0LHLTM), 

“Faiza Beauty Cream – 30 gram – Whitening Cream ‐ Anti Pimple Cream –

Freckle Cream” (ASIN B00XUY6FL6), “Face Fresh Beauty Cream” (ASIN 

B00ZP38YQY), “Monsepa Express Peeling Remove Dark Sports Face Cream” 

(ASIN B0030K8GJY), “Meiyong Super Extra Whitening Cream Seaweed Face 

Lift Natural Algae” (ASIN B00CVJKBDE), “Seaweed Cream – Extra 

Whitening & Face Lift” (ASIN B008XRYQUM), “Meiyong Seaweed Extra 

Whitening Formula & Face Lift Cream” (ASIN B00AS71WWU); “Seaweed 

Cream – Extra Whitening & Facelift” (ASIN B00UPXPMYQ), “Meiyong 

Brand Super Extra Whitening Cream Seaweed Face lift” (ASIN 

B00VCN3Z7Y), and “Meiyong Super White Cream Extra Whitening & Face 

Life Advanced Super Revitalizer” (ASIN B00HZFSBYU). 
5

California Department of Public Health (CDPH) found 8,900 ppm mercury in 

a sample of Monsepa Express Peeling cream tested in May 2013, 13,000 ppm 

mercury in a sample of Monsepa Express Peeling cream tested in December 

2013, and a 2013 test for the California Department of Justice found 12,000 

ppm mercury in a sample of Monsepa Express Peeling cream and 20,000 ppm 

mercury in a sample of Monsepa Whitening Peel. 

Additionally, in 2013, the European Union’s Rapid Alert System for 

dangerous non-food products (RAPEX) issued two alerts for Faiza Beauty 

Cream, one reporting 5,430 ppm mercury and the other reporting 5,940 ppm 

mercury, and an alert for Face Fresh Beauty Cream reporting 4,620 ppm 

mercury. 

The CDPH issued a health risk warning on January 14, 2014, for 

certain imported skin-lightening creams that had been found to contain high 

levels of mercury, including “Monsepa Bleaching Express Peeling.” 

Lee provided Amazon a 60-day “Notice of Violation” pursuant to 

Proposition 65 (Health & Saf. Code, § 25249.7, subd. (d)) dated May 22, 2014. 

He filed his complaint for civil penalties and injunctive relief on August 25, 

2014. 

After a bench trial in January 2019, the trial court ruled in favor of 

Amazon, finding the company immune from liability under section 230 of the 

federal CDA (47 U.S.C. § 230).7 The court also found that while Amazon 

could have a duty to warn under Proposition 65 for third-party sales of the 

products at issue, Lee failed to prove each element of his claim under 

Proposition 65—specifically, that Lee did not prove each of the products at 

issue contained mercury, that test results finding mercury in a unit of the 

products at issue should be generalized to other units of that product or 

7 Further references to “section 230” are to title 47 United States Code.
6

similar products, that the creams sold on Amazon’s Web site were actually 

used by consumers, and that Amazon had actual knowledge the products 

contained mercury at the time they were purchased without a Proposition 65 

warning. 

Mercury in Skin-Lightening Creams

As described by Lee’s expert witness on mercury in skin-whitening 

creams and resultant health risks, Dr. Gina Solomon,8 mercury exists in 

three forms (elemental, inorganic and organic), all of which are toxic, with 

serious effects on bodily systems and organs at a cellular level. Inorganic 

mercury (the form used in skin creams) is “very, very toxic” to kidney 

function and also has serious effects on reproductive function and fetal 

development. Animal studies consistently show reduced fertility, fetal 

viability and birth weights at “pretty low level exposures.” In both humans 

and rodents, prenatal exposure at “pretty low levels” has been shown to 

result in profound deafness. Solomon testified that the levels of mercury 

found in skin creams are in the same range as those shown to cause these 

8 Dr. Solomon was a principal investigator at the Public Health 

Institute and clinical professor in the Division of Occupational 

Environmental Medicine at the University of California San Francisco. Her 

background included serving as the deputy secretary for the California 

Environmental Protection Agency, where her work included developing 

sampling plans for hazardous material cleanup, including work with metals 

such as lead, mercury and arsenic, and extensive work with OEHHA on 

Proposition 65 issues; teaching medical students, residents and fellows, and 

supervising them on clinical work regarding complex toxicology issues; 

teaching continuing medical education classes for doctors and developing the 

original curriculum for a CDPH program for physicians on the human health 

effects of mercury; and treating patients exposed to dangerous levels of 

mercury from a skin cream product and collaborating with researchers 

investigating the case, which led to the CDPH’s health alert on mercury in 

skin-lightening creams, as well as work on the issue with other states’ health 

departments. 
7

adverse effects in rodents, which tend to be less sensitive than humans to 

many neurologic and reproductive effects. 

The adverse effects of mercury are not limited to the direct users of the 

creams. The form of mercury used in skin-lightening creams—inorganic 

mercury—can release mercury vapor, especially in warm conditions.9 The 

CDPH has found mercury contamination resulting from use of skin creams 

requiring extensive decontamination of houses, including items such as 

washing machines, mattresses and sofas, and disposal of items like toys, 

towels, and bedding as hazardous waste. In the case of a family Solomon 

treated for mercury poisoning, mercury vapor was found emanating from the 

hands of the woman who used the cream, and decontamination of her hands 

took a month of repeated applications of a binding compound. 

The primary users of skin-lightening creams are women, principally 

women of color. At the time of trial, the CDPH was conducting educational 

events in communities where the creams are known to be used, as well as a 

buyback program for people to return the creams and receive money to 

purchase substitutes. 

Not all skin-lightening creams contain mercury: CDPH tests of more 

than 100 skin-lightening creams found seven that were positive for 

mercury.10 Of a total of five ingredients known to whiten skin, the only one 

permitted in the United States is hydroquinone. 

9 Solomon explained that mercury exists in three different forms 

(elemental, inorganic and organic), which have different properties, but can 

“inter-covert” in different settings. 

10 None of the products tested in this study came from Amazon. The 

CDPH witness who testified at trial explained that they were collected from 

markets in targeted communities and online stores serving immigrant 

populations identified in the literature, or through poisoning investigations, 

as using these creams. 
8

Solomon testified that public health issues with skin-whitening creams 

involve creams imported from certain countries in Asia, Mexico, and in a few 

cases Africa; Lee’s expert witness on cosmetic chemistry and Proposition 65 

warnings, David Steinberg,11 testified that in his experience most skinbleaching products containing mercury were made in Pakistan. Both 

testified that the claims made on listings on Amazon for the products Lee had 

tested—referring to removing dark spots, whitening skin and treating 

acne12—were “red flags” indicating the product was for skin bleaching and 

11 Steinberg was the president of a consulting company that deals with 

“regulations and chemistry of cosmetics and topical pharmaceutical 

products.” His 50 years’ experience in the cosmetic industry included 

working on product development involving the chemistry of cosmetics, 

advising cosmetics companies on product and regulatory issues, teaching and 

publishing on the chemistry of cosmetics, and lecturing on quality assurance 

for cosmetics; he had experience with mercury in cosmetics and specifically in 

skin-lightening products, and with issues under Proposition 65. 

12 On the Amazon Web site, a listing for “Faiza Beauty Cream” (ASIN 

B00V0LHLTM) claims to “remove freckles & dark spots”; another—with the 

same product image, but a different ASIN (B00WORM8R0) and different 

Universal Product Code claims to be “the only cream that cleans pimples, 

wrinkles, marks, hives even dark circles under the eyes and turns your skin 

white.” The product listing for “Meiyong Super Extra Whitening Cream 

Seaweed Face life natural Algae” (ASIN B00CVJKBDE) includes “Help 

relieve acne, freckles and dark spots on the performance give a white skin.” 

Monsepa Express Peeling Remove Dark Spots Face Cream (ASIN 

B0030K8GJY) claims it “eventually removes even the deepest types of 

freckles, dark spots, butterfly spatches and yellow spots from your face” and 

“is specially effective to eradicate and even out acne scars.” Face Fresh 

Beauty Cream’s (ASIN B00ZP38YQY) claims include, “Best whitening 

cream,” “Anti Wrinkles,” “lightening dark spots,” and “Turns Your Skin 

White.”
9

might contain mercury.13 This was particularly the case where a product 

claimed to both whiten skin and treat acne, because mercury is the only 

ingredient known to do both. 

Solomon testified that the mercury concentrations found in the creams 

tested in this case meant mercury was “definitely not” a “trace amount,” but 

rather an intentionally added active ingredient; the concentrations were 

“absolutely inconsistent” with mercury being a trace contaminant. The range 

of concentrations in the tested samples, between 2,000 and 21,000 milligrams 

per kilogram (2,000 to 21,000 ppm or .2 to 2 percent), was consistent with 

active ingredients in other consumer products, such as 2 percent of the 

herbicide in RoundUp, 1 percent cortisone in anti-inflammatory skin cream 

or .2 percent sodium fluoride in toothpaste. Prior to her work on this case, 

Solomon had seen the 2014 CDPH press release warning consumers about 

mercury in certain skin-lightening creams, including Monsepa, and believed 

the product contained mercury because she considered product warnings 

from the CDPH highly credible; the test results Lee obtained in 2017 

confirmed her opinion and showed the formula had not been changed despite 

the health alert. 

Based on the test results and language used in the Amazon listings for 

the skin whitening creams, Solomon was certain all units of the products 

tested would contain mercury. Solomon testified that “very little actual 

testing” is necessary to answer the “yes or no” question whether an 

intentionally added ingredient is present in a product, and regulatory 

agencies “not infrequently” base a decision on a single sample or very few 

13 Amazon stipulated that all 27 products identified in the second 

amended complaint purported to be skin-lightening or skin-bleaching 

products. 
10

samples. Factors such as how a product was stored and whether multiple 

manufacturers were used, could be relevant to a contamination issue, but 

would be irrelevant in determining whether an intentional ingredient was 

present because manufacturers are reluctant to change their formulas: They 

want consistency in the appearance, smell, and effect of consumer products, 

as consumers notice differences and do not like them. Solomon was careful to 

clarify that extrapolation from test results on one unit to other units of the 

same product was appropriate for “yes/no test results” for presence of 

mercury, not the exact concentrations detected. 

Steinberg similarly testified that the test results in evidence were 

sufficient to conclude the products at issue contained mercury because there 

was no way the amount of mercury found in samples Lee had tested could be 

due to a trace contaminant that might vary between batches or lots; it had to 

be a deliberately added ingredient He testified that in making emulsions 

(the form of the skin creams at issue), at least three or four tests are usually 

run per batch for purposes of quality control and quality assurance, to ensure 

uniformity and confirm the product meets specifications and is free of 

contamination, and most companies test each batch before filling individual 

containers for consumer sales. Testing of multiple batches of each product is 

not necessary to determine whether mercury is an ingredient in a cosmetic 

product, however, because at levels seen in this case, it has to have been 

deliberately added. The high levels of mercury found in the five samples Lee 

had tested, together with the products’ claims of skin whitening as the 

intended use, made Steinberg “very, very certain” other batches or lots of the 

same product would all contain mercury as an ingredient.” 

Steinberg acknowledged the possibility there could be variations in the 

chemical makeup of the products between batches; that he did not have 
11

information about the companies’ specific manufacturing and packaging 

practices or know details such as when they began using mercury in their 

skin-bleaching products or whether they had another version of the product 

that used a different ingredient in place of mercury; and that some companies 

use different formulas in different countries for products branded and sold as 

the same product. He testified that if a company does not follow “current 

good manufacturing procedures” (cGMPs), which include matters such as 

manufacturing and testing methods and meeting product specifications, “all 

bets are off in terms of product consistency across units and batches and 

lots,” and many variables could make a difference in this regard. Steinberg 

did not know whether the companies here followed cGMPs, but he had reason 

to believe the products were sourced in Pakistan and no reason to expect 

companies in Pakistan to follow cGMPs. 

Nevertheless, Steinberg testified he could be “very certain” the 

products tested here contained mercury without analyzing every package 

because “cosmetic-like products” are manufactured in “larger amounts” with 

“a consistent formulation,” mercury is the active ingredient, and cosmetic 

companies do not like to change formulations of creams “unless it’s absolutely 

mandatory, or marketing just absolutely demands it, because it’s very timeconsuming” and a significant added expense. A different chemical could not 

simply be substituted for mercury; the product would have to be “totally 

reformulate[d]” because the emulsion would not be stable. 

Steinberg was shown a customer comment on the product page for the 

Monsepa cream Lee had tested saying the news had reported on January 9, 

2014, that the product contained high levels of mercury, providing a link to 

the official alert on the CDPH Web site, and asking vendors to stop selling 
12

it.14 Steinberg testified he would advise a company that received a comment 

like this to immediately find out if there was mercury in the product. He 

further testified that as part of good business practices, it is important for a 

company offering cosmetics for sale on the Internet to monitor public health 

alerts and announcements by governmental agencies. His advice to a client 

that received the May 22, 2014, notice of violation Lee sent to Amazon would 

be to confirm whether the product it was manufacturing or selling contained 

mercury and, if so, recall the product and notify the FDA. Once Amazon was 

alerted to the presence of mercury in the creams, it should have immediately 

notified every purchaser of the product to discontinue use and halted sales of 

the product. 

Dr. Patrick Sheehan, Amazon’s expert witness on risk assessment and 

evaluation of health risks from chemical exposures,15 agreed that mercury is 

a known ingredient in skin-lightening creams and that in each of the tested 

samples in this case, mercury was an ingredient, not a contaminate. He 

14 The comment expressed skepticism that the product was made in 

France (as was also stated on the bottle and packaging of the sample Lee had 

tested) because “the EU has strict cosmetic regulations.” Steinberg had 

“serious doubt” the product was made in France based on his experience 

dealing with officials in France, who would not have permitted it, and his 

knowledge that “these types of products using these types of ingredients . . . 

have been restricted almost exclusively to Pakistan.”

15 Dr. Sheehan had worked in the field of risk assessment for 40 years, 

the last 19 of which he had been a consultant with a company called 

Exponent, advising clients on historic, current, and potential exposures and 

associated risks. He had taught part of a course on risk assessment at San 

Diego State University School of Public Health for about 20 years, worked 

with governmental committees on developing and defining methods to assess 

health risks, done more than 200 Proposition 65 risk assessments, and had 

experience evaluating mercury exposure in the contexts of site risk 

assessment, waste disposal, and a project involving removal of gas pressure 

regulators from homes. 
13

testified, however, that these results could not be generalized beyond the 

units tested. Sheehan testified that test results from a single unit cannot be 

extrapolated even to other units in a batch because it is necessary to account 

for variability between units resulting from uneven distribution of chemicals 

within a batch, or between batches for products. Factors influencing 

variability include changes in ingredients or sources of the ingredients, 

changes or inconsistency in manufacturing processes and changes in the 

recipe for the product. Sheehan testified that the standard practice is to 

sample individual units within a batch to “understand the conditions of the 

individuals that make up that batch,” then “do the same thing in all of the 

batches that are of interest within the time frame of the evaluation so that 

you can say with confidence what is a condition of the population that is 

made up of all of those batches of individuals within those batches.” 

According to Sheehan, the literature on skin-lightening creams reflects 

variability as to measurable added mercury, with some batches having no 

detectable mercury and others having levels “related to added mercury.” 

Asked about the CDPH investigation in which seven of 120 samples of skinlightening creams tested positive for significant amounts of mercury, 

Sheehan testified the data suggested there would be detectable added levels 

of mercury in relatively few skin creams. He disagreed with Steinberg and 

Solomon because they only evaluated the individual units tested, with no 

effort to “assess variability among batches or among products.” Asked if they 

followed “appropriate scientific method,” Sheehan testified, “I don’t believe 

they followed any method. They made some assumptions. So no, they did 

not follow any sort of standard method for characterizing variability within a 

product.” 
14

Sheehan stated that Steinberg’s “assumption” that “under good 

manufacturing practice one would expect to find mercury in different batches, 

if you found it in one batch” was not supported by the data and literature, 

which contain “examples where there was mercury detected at some batches 

of a lot and not in others.” In Sheehan’s view, it did not make any difference 

that mercury was an added ingredient in the skin-lightening creams for the 

same reason: The literature indicated that “any measurement in one 

batch . . . will not tell you what is happening within the population of that 

skin-lightening cream.”

Sheehan acknowledged that a study he conducted on whether users of 

talcum powder in the 1960’s and 1970’s were exposed to asbestos was based 

on analysis of five individual containers, each a different product. He also 

acknowledged that at his deposition he did not recall having worked on a 

cream applied to the body other than sunscreen, which he declined to answer 

questions about, and that he had never previously been an expert in a case 

involving mercury and skin-lightening cream, advised a client regarding 

mercury in skin-lightening creams, done any work evaluating the presence or 

absence of mercury in cosmetics, or otherwise had experience with analyzing 

heavy metal exposure in creams. 

Amazon’s Marketplace

As described by Christopher Poad, Director of Amazon Business 

International, Amazon both sells products directly to customers through its 

“Amazon Retail” business and operates a “marketplace” through which thirdparty sellers sell products to customers. Approximately 2.5 million third 

parties list and sell approximately 600 million unique products on the 

Amazon Web site. In 2018, the total value of products sold on the Amazon 
15

Web site worldwide was approximately $300 to $350 billion, 50 to 55 percent 

of which ($150 to $175 billion) were sales by third parties.

Amazon provides third-party sellers with the ability to list their 

product for sale, provide a title, description and image for the listing, and 

have Amazon collect payment on the sellers’ behalf. Sellers can choose to 

fulfill orders themselves, making their own arrangements for warehousing 

and shipping, or use Amazon’s “Fulfillment by Amazon” or “FBA” service. 

With FBA, the third-party seller’s products are stored in an Amazon 

fulfillment center (warehouse), then shipped to the customer by Amazon 

when the seller makes a sale. For third-party sales, ownership of the product 

is transferred from the seller to the customer without Amazon taking title. 

By contrast, for Amazon Retail, Amazon purchases the merchandise from a 

supplier, owns it, and then resells it to the customer. 

The products at issue in this case were all placed on the Amazon Web 

site by third-party sellers, and at least one used the FBA service. 

Third-party sellers are required to consent to Amazon’s “Business 

Solutions Agreement,” which details matters including indemnification and 

insurance requirements for sellers. Amazon charges fees to sell products on 

the marketplace, which it earns when the seller completes a sale and the 

product is shipped to the customer. Customers use the Amazon Web site to 

complete purchases and in most transactions, there is no communication 

between customers and third-party sellers; if there is, it goes through the 

Amazon platform. Amazon’s Web site does not provide contact information 

for third-party sellers; it offers a “contact seller” option through which a 

customer can send a message, which Amazon forwards to the seller, and the 

seller can respond. 
16

Each unique product on the Amazon Web site has its own product 

description page. The content for this page, including product name, 

description, price, and quantity available for sale, is provided by the thirdparty seller. When a third party creates a new product listing, if the product 

does not already exist on the Web site, it is assigned a new ASIN. Materials 

for sellers “encourage and require” them not to create duplicate listings and it 

is not in their interest to do so, because if there are two pages for a single 

product, each will only get half as many people looking at it. Amazon has 

software that scans the product catalog for products that look identical, or 

“very, very similar,” and merges such products onto a single page, and the 

customer service team is able to merge pages together if someone reports 

duplicates. According to Poad, it is not sufficient to look at product images to 

determine whether two are the same because manufacturers may change the 

contents without changing packaging and many use stock images for multiple 

products; instead, one must look at unique identifiers such as the Uniform 

Product Code, descriptions and titles. 

During the process for setting up the product description page, sellers 

“have the ability to flag whether the product they are selling requires a 

Proposition 65 warning for California residents,” and if they select this 

option, a warning is displayed on the product description page that links to a 

page in the customer help section of the Web site. In its “policies and 

agreements” for sellers, Amazon provides a list of examples of “prohibited 

listings” that includes “Products and ingredients that the [FDA] has 

determined present an unreasonable risk of injury or illness, or are otherwise 

unsafe, such as . . . [s]kin creams containing mercury.” 

Amazon’s director of worldwide product compliance and safety, David 

Kosnoff, testified in his deposition that the Amazon product safety team in 
17

Europe reviews products listed on RAPEX notifications and these products 

are removed from Amazon’s European Web sites, but not necessarily those in 

other countries. If a product was listed on RAPEX in 2015, Amazon would 

have searched its European Web sites and, if the product was listed, would 

have taken down the listing and notified customers; the United States 

marketplace would not have been impacted. A recall in one country would 

not necessarily trigger recall in another because it can be difficult to 

determine whether products that appear identical in different countries are 

actually the same product.

Kosnoff testified Amazon would have been aware of the 2013 RAPEX 

notification for Faiza Beauty Cream. He did not know whether the product 

was listed on Amazon’s European Web sites. He was aware a “very similar” 

product was listed on the United States Web site and did not believe any 

action would have been taken to notify the United States marketplace of the 

European recall. The record documents sales of Faiza Beauty Cream on the 

Amazon Web site through late 2015. 

Face Fresh, which was also the subject of a 2013 RAPEX notification, 

was being sold on Amazon’s Web site as of January 16, 2019. 

After Lee’s May 22, 2014, 60-day notice of violation, which listed 

Monsepa Express Peeling Night Face Cream as an example of “[s]kinlightening creams,” on June 11, 2014, Amazon added a Proposition 65 

warning to the listing for Monsepa Express Peeling cream (ASIN 

B0030K8GJY). Between these dates, there were five sales of this product 

(May 23, 29, 31, June 2, 6). Amazon removed the listing from the Web site on 

August 12, 2014. 
18

DISCUSSION

We begin with the elements of the Proposition 65 claim because, as will 

be seen, the nature of this claim is critical to the question of immunity under 

section 230 of the CDA.

I.

The trial court found Lee did not prove that each of the 27 products 

identified in the second amended complaint contained mercury because Lee 

purchased and tested only one unit each of five products.16 The court 

concluded the product detail pages from Amazon’s Web site that Lee 

introduced into evidence did not establish the 27 products originally 

identified were the same products he tested because the pages were for only a 

few products and contained “multiple material differences, including different 

“product names, pictures, sellers, descriptions, ASINs and UPCs.” The court 

therefore limited Lee’s claims to “the four products he purchased on Amazon 

and tested.” 

Moreover, the court found Lee did not prove the test results showing 

mercury in one unit of a given product should be generalized to other units of 

that product or similarly named ones because Lee did not introduce evidence 

of “how, when, where or by whom any of the tested units were manufactured, 

filled, stored, or distributed, including any lot or batch information for the 

tested samples,” leaving no scientific or evidentiary basis for determining 

whether other units of the same product or similar ones under the same 

16 The trial court referred to Lee having tested four products purchased 

from Amazon’s Web site, plus one unit of a fifth product purchased on 

www.aztopsel.com. As we understand the record, the five samples Lee had 

tested for this case were each from a product with a distinct ASIN, purchased 

on Amazon’s Web site, although the two Meiyong products had the same 

product name and the Monsepa product was shipped from aztopsel.com. 
19

brand name contained mercury. The court pointed to a comment on the 

laboratory report for one of the samples Lee had tested, which stated, “Please 

note that these results apply only to the sample(s) submitted for this report. 

Samples from a different portion of the same lot may produce different 

results.” The court also observed that the RAPEX notices identified batch 

numbers for the product involved. The court rejected the opinions of Lee’s 

expert witnesses that the test results Lee obtained could be generalized to 

untested units, finding them contradicted by the testimony of Amazon’s 

expert witness and two of Lee’s own witnesses. 

Lee argues the trial court’s conclusions are both legally and factually 

unsupported. Preliminarily, he points out that the trial court ignored his 

narrowing of the products at issue from the 27 identified by ASIN in the 

second amended complaint to four products appearing under 11 ASINs on 

Amazon’s Web site, and argues the trial court erred in limiting the case to 

four ASINs for which laboratory tests were obtained. More fundamentally, 

he argues the trial court erred in concluding test results for one unit of a 

given product could not be extrapolated to other units of the same product for 

purposes of determining whether Proposition 65 warnings were required.

Amazon treats these issues as purely factual, to be reviewed under the 

substantial evidence test. Focusing on descriptions of this test as requiring 

us to “look only to the evidence supporting the prevailing party” and “discard 

evidence unfavorable to the prevailing party” (Felgenhauer v. Soni (2004) 

121 Cal.App.4th 445, 449), Amazon argues the court’s conclusions were 

supported by its witnesses’ testimony—Poad’s, as to each ASIN representing 

a distinct product, and Sheehan’s (along with Steinberg’s and Dr. Brian 

Lee’s) as to a test of one unit being insufficient to demonstrate the presence of 

mercury in another unit of the same product.
20

To the extent these issues are purely factual, Amazon is of course 

correct that we review the trial court’s decision under the substantial 

evidence test. “ ‘In determining whether a judgment is supported by 

substantial evidence, we may not confine our consideration to isolated bits of 

evidence, but must view the whole record in a light most favorable to the 

judgment, resolving all evidentiary conflicts and drawing all reasonable 

inferences in favor of the decision of the trial court. (People v. Johnson (1980) 

26 Cal.3d 557, 576–578.) We may not substitute our view of the correct 

findings for those of the trial court; rather, we must accept any reasonable 

interpretation of the evidence which supports the trial court’s decision.’ ” 

(DiMartino v. City of Orinda (2000) 80 Cal.App.4th 329, 336, quoting Beck 

Development Co. v. Southern Pacific Transportation Co. (1996) 44 

Cal.App.4th 1160, 1203–1204.) Nevertheless, we do not defer to the trial 

court’s decision entirely. (DiMartino, at p. 336.) “Substantial evidence is a 

deferential standard, but it is not toothless.” (In re I.C. (2018) 4 Cal.5th 869, 

892.) “ ‘ “We may not uphold a finding based on inherently improbable 

evidence or evidence that is irrelevant to the issues before us. [Citation.]” 

[Citation.]’ (Richardson v. City and County of San Francisco Police Com.

(2013) 214 Cal.App.4th 671, 692.)” (Daugherty v. City and County of San 

Francisco (2018) 24 Cal.App.5th 928, 944.) 

In particular, “expert testimony does not constitute substantial 

evidence when based on conclusions or assumptions not supported by 

evidence in the record (Hongsathavij v. Queen of Angels etc. Medical 

Center (1998) 62 Cal.App.4th 1123, 1137), or upon matters not reasonably 

relied upon by other experts (Pacific Gas & Electric Co. v. Zuckerman (1987) 

189 Cal.App.3d 1113, 1135). Further, an expert’s opinion testimony does not 

achieve the dignity of substantial evidence where the expert bases his or her 
21

conclusion on speculative, remote, or conjectural factors. (Leslie G. v. Perry & 

Associates (1996) 43 Cal.App.4th 472, 487.) When the trial court accepts an 

expert’s ultimate conclusion without critically considering his or her 

reasoning, and it appears the conclusion was based on improper or 

unwarranted matters, we must reverse the judgment for lack of substantial

evidence. (Pacific Gas & Electric Co. [at p.] 1136.) On the other hand, the 

trial court is free to reject testimony of a party’s expert, so long as the trier 

does not do so arbitrarily. (Howard v. Owens Corning (1999) 72 Cal.App.4th 

621, 633.)” (People ex rel. Brown v. Tri-Union Seafoods, LLC (2009) 

171 Cal.App.4th 1549, 1567–1568.)

We turn first to the trial court’s conclusion that a laboratory test 

finding a high level of mercury in one unit of a skin-lightening cream is an 

insufficient basis for concluding other units of the same product contain 

mercury. All the relevant experts—Steinberg, Solomon, and Sheehan—

agreed that because of potential variability in factors such as ingredients, 

supply sources, manufacturing processes, and storage conditions, multiple 

samples would have to be tested to ensure consistency of a product within a 

batch and across multiple batches. Such testing would be necessary, all 

agreed, to determine matters such as the amount of an intentional ingredient 

or presence of a contaminant. 

The question in the present case, however, is whether the test results 

for one unit of a product could be sufficient to determine whether mercury 

was present in other units—not whether any specific amount was present, 

just whether it was present at all. Lee’s experts testified that answering this 

“yes/no” question did not require testing more than one unit of each product, 

or considering variables such as manufacturing and packaging procedures, 

because the amount of mercury in the unit tested was so high that it 
22

demonstrated mercury was the intentionally added active ingredient—the 

ingredient used to achieve the product’s intended purpose. Because it was 

the active ingredient, while there might be variation in the actual 

concentration of mercury from one unit or batch to another, there would not 

be units in which mercury was completely absent. Significantly, Sheehan, 

too, agreed that the levels of mercury found in the tested samples indicated it 

was an intentional ingredient, not a contaminant. 

In rejecting Solomon’s and Steinberg’s conclusions as to generalizing 

the test results, the trial court first cited the deposition testimony of 

Dr. Brian Lee, who Lee had identified as an expert witness but did not 

present as a witness at trial, that “there is insufficient information to 

conclude that any untested unit contains mercury.” 

Dr. Lee testified at his deposition that his only assignment for this case 

was to determine “how much an exposure might occur to users.” Asked

whether he would be offering an opinion that any unit of a product at issue in 

the case contained mercury other than the 11 samples for which he was given 

lab test results, Dr. Lee first clarified that the questioner meant “all of the 

other units that are on the market,” then responded, “No. I only know what 

is in these products. These may represent what’s in the other products, but 

until you actually test what is in the products, there could be several 

batches.” 

The trial court’s summary of Dr. Lee’s deposition testimony makes it 

appear more definitive than it actually was. The questioner explained he was 

asking about “units” of a product, not “product,” but Dr. Lee’s response 

referred to “products,” suggesting he was saying the products tested might or 

might not represent other products, not necessarily that one unit of a given 

product might or might not represent other units of that product (although 
23

his references to “batches” creates some ambiguity). Moreover, especially in 

light of his assignment to determine “how much an exposure might occur to 

users,” the deposition excerpt read into the record at trial does not make clear 

whether Dr. Lee understood the question as asking about absolute presence 

or absence of mercury across units of a given product or about potential 

variability in the amount of mercury in one unit as compared to another, or 

whether he considered the significance, if any, of mercury being the active 

ingredient in the creams.

Dr. Sheehan was expressly asked whether it made any difference to 

him that mercury was an intentionally added ingredient and testified that it 

did not. His response, while not entirely clear, appears to concern variability 

among batches without explaining how variability would extend to complete 

absence of the product’s active ingredient.17 The trial court summarized 

Dr. Sheehan’s testimony as stating that “there is variation in the mercury 

content of skin-lightening creams, even when one expects to find mercury, 

and that a scientific method is needed to generalize from one unit to other 

units and other batches.” But as far as we are aware, Dr. Sheehan did not 

explain why this is so in the case of a product intended to address cosmetic 

issues for which mercury is an effective treatment and demonstrated—albeit 

in one or a small number of samples—to contain such high levels of mercury

that it must be an intentional ingredient.

17 Dr. Sheehan responded, “For the same general reason that I gave for 

the other, that is if you look at the literature, is if you find in one batch no 

skin-lightening creams and in another batch, you find some measurable 

added level of skin-lightening creams, it suggests that any measurement in 

one batch. It will not tell you what is happening within the population of 

that skin-lightening cream.” 
24

The portions of Steinberg’s testimony that the trial court saw as 

contradicting his own and Solomon’s testimony that the test results could be 

generalized to the product line from which the sample was taken are not, in 

fact contradictory. The court noted Steinberg’s testimony that “at least three 

or four tests per batch would be needed to ensure uniformity of a cosmetic 

product,” that in order to predict consistency across units and batches, it is 

necessary to know whether a product was manufactured according to current 

cGMPs, and that, in effect, he did not expect cGMPs were followed for the 

products at issue. This testimony, however, addressed uniformity and 

consistency of the product. Steinberg expressly distinguished the testing 

necessary to ensure uniformity and consistency from that necessary to 

determine whether mercury is present in units of a specific skin-whitening

product other than the unit tested where mercury is known to be the active 

ingredient in skin-whitening products because of its effectiveness in 

lightening skin, is the single ingredient known to also treat acne, as 

advertised for some of the creams at issue, and is found in high 

concentrations in one or a few samples of that specific skin-lightening 

product.

Amazon’s statement that this is “a rare case where all experts on both 

sides agreed that it was not possible to extrapolate test results from a single 

unit of four products to all other units of that product line” is thus divorced 

from the record. This was Dr. Sheehan’s testimony, but not Dr. Solomon’s or 

Steinberg’s; Lee’s witnesses both testified that in the circumstances here, the 

tests could be generalized to other units of the product line from which the 

tested sample was taken.

The trial court also noted that the National Food Lab’s report for the 

samples of Monsepa creams tested for the California Department of Justice
25

in 2013 contained the comment, “Please note that these results apply only to 

the sample(s) submitted for this report. Samples from a different portion of 

the same lot may produce different results.” This comment, again, refers to 

the undisputed potential for variability in uniformity and consistency across 

lots. It does not address the disputed question whether test results finding a 

high level of the active ingredient in a single sample can be generalized to 

conclude all samples of that product will have some amount of the active 

ingredient.

Finally, the trial court noted that the RAPEX notices “delineate batch 

numbers of any product involved within the notice(s).” The observation is 

only partially accurate. The RAPEX notice for Face Fresh Beauty Cream 

provided information in the spaces for “Type/number of model” and “Batch 

number/Barcode,”18 but the RAPEX notice for Faiza No. 1 Beauty Cream, in 

these spaces, stated “Unknown.” Moreover, the warning issued and report of 

action taken for both RAPEX notices pertained to “the product,” unlimited by 

batch number or otherwise. Both notices, for “Risk description,” stated that 

“[t]he product poses a chemical risk because it contains mercury” and “[t]he 

product does not comply with the Cosmetics directive 76/768/EEC.” Both 

notices reported the “[m]easures adopted by notifying country” as “Voluntary 

measures: Withdrawal of the product from the market.” 

In sum, the trial court’s stated reasons for concluding that a laboratory 

test finding a high level of mercury in one unit of a skin-lightening cream is 

an insufficient basis for inferring other units of the same product contain 

mercury do not withstand scrutiny. The only evidence directly supporting 

18 The RAPEX notice for Face Fresh Beauty Cream, for “Type/number 

of model,” stated, “Unknown Batch number: No 1192 - MFG 1 3 12 EXP 1 3 

14” and for “Batch number/Barcode” stated, “1 41960 001908.”
26

the trial court’s conclusion, Dr. Sheehan’s testimony, failed to explain the 

basis for his rejection of the other experts’ distinction between testing to 

determine uniformity and consistency of a product and testing to confirm the 

absolute presence or absence of the active ingredient in a product. Indeed, 

Dr. Sheehan’s testimony on this point was inconsistent with the design of his 

own investigation of asbestos in talcum powder. Dr. Sheehan acknowledged 

that a study he conducted on whether users of talcum powder in the 1960’s 

and 1970’s were exposed to asbestos reported on the health risk from using 

talcum powder during that period based on analysis of five individual 

containers, each a different product. These five samples of five different 

products were the basis for what appears to be a broad conclusion in an 

article published in the peer-reviewed scientific literature that “[t]he absence 

of detectable asbestos fibers confirms the previous findings that most 

historical cosmetic talcum powder products did not produce asbestos fiber 

exposures.” Additionally, while Solomon and Steinberg both had 

considerable experience with the specific subject of testing here—mercury in 

skin-lightening creams—Sheehan did not recall having worked on a cream 

applied to the body other than sunscreen and had no experience with 

mercury in cosmetics or heavy metals in creams.

Dr. Sheehan’s testimony is also difficult to reconcile with the practice of 

governmental entities responsible for regulating harmful consumer products. 

A CDPH employee who helped write the January 2014 news release warning 

against use of certain skin-lightening creams testified that the sample of 

Monsepa Express Peeling cream that was the basis for the alert did not have 

batch or lot numbers or other such identifying information and the alert was 

issued “for any and all products that have this appearance in name.” 

Dr. Solomon testified that “it’s something regulatory agencies not 
27

infrequently will do based on a single sample or very few samples.” This 

makes obvious sense where the issue is whether a product contains the 

chemical in question at all, and not the precise amount in any individual 

unit. 

Proposition 65 imposes a duty to warn based on presence of a listed 

chemical in a product, without requiring uniformity across individual units in 

the precise amount of the chemical in a given unit. When the chemical at 

issue is the product’s active ingredient, its complete absence in an individual 

unit would be fortuitous. “Proposition 65 is a ‘right to know’ statute 

requiring companies that expose consumers to carcinogens or reproductive 

toxins to provide a reasonable and clear warning. (Health & Saf. Code, 

§ 25249.6.) It is a remedial law, designed to protect the public, and thus we 

construe its provisions broadly to accomplish that protective purpose. (People 

ex rel. Lungren v. Superior Court (1996) 14 Cal.4th 294, 314.)” (Center for 

Self-Improvement & Community Development v. Lennar Corp. (2009) 

173 Cal.App.4th 1543, 1550–1551.) Once it is confirmed that a product 

contains a high level of a chemical listed as a toxin under Proposition 65 as 

an intentional ingredient (not as a contaminant), it would be inconsistent 

with the statutory purpose to require the kind of testing necessary to ensure 

product uniformity or consistency before enforcing the duty to warn.

Amazon’s assertion that there was no evidence mercury was an 

intentional ingredient in these products is without basis in the record and 

directly inconsistent with even its own expert’s testimony: Sheehan fully 

agreed that mercury was present in the samples tested in amounts 

demonstrating it was an ingredient, not a contaminant. Amazon points to 

the CDPH testing that found most skin-lightening creams on the California 

market did not contain mercury, but that does not refute the undisputed 
28

evidence that the products at issue here tested positive for mercury, at very 

high levels.

Given the undisputed evidence that samples of five skin-lightening 

products purchased on Amazon’s Web site contained high levels of mercury as 

an intentionally added ingredient, there is no basis for a conclusion that Lee 

failed to prove this element of his case with respect to these products, at a 

minimum. If Lee proved the other elements of his claim, it cannot be 

rejected—at least for these specific products—on the ground that he failed to 

prove the products contained mercury.

Beyond the products tested, a question remains. The trial court 

concluded Lee did not prove each of the 27 products listed by ASIN in the 

second amended complaint contained mercury because the evidence did not 

establish that they were the same products as the ones19 tested. Lee

subsequently limited his claims to 11 products that he claimed were the same 

as those tested despite having been assigned different ASINs. Given our 

rejection of the trial court’s conclusion that Lee failed to prove the tested 

products contained mercury, if the remaining elements of his claims were 

also established as to these specific products, the trial court will have to 

determine whether the untested products within the identified group of 11

were in fact the same products as the ones tested.

II.

As earlier stated, Proposition 65 provides that “[n]o person in the 

course of doing business shall knowingly and intentionally expose any 

19 The trial court referred to four products having been tested for this 

case. As earlier indicated, five samples were tested, one each for the Faiza, 

Monsepa, and Face Fresh creams, and two for Meiyong skin-lightening 

creams with the same name but assigned different ASINs on Amazon’s Web 

site. 
29

individual to a chemical known to the state to cause cancer or reproductive 

toxicity without first giving clear and reasonable warning to such individual, 

except as provided in Section 25249.10.” (Health & Saf. Code, § 25249.6, 

italics added.) Lee argues the trial court erred in requiring him to prove 

Amazon had actual knowledge that the products at issue contained mercury, 

maintaining that constructive knowledge is sufficient to trigger the duty to 

provide Proposition 65 warnings. In general, “[p]roof of actual knowledge 

focuses on what information a defendant must have been aware of, while 

proof of constructive knowledge rests on a defendant’s duty to discover 

information.” (People v. ConAgra Grocery Products Co. (2017) 17 Cal.App.5th 

51, 84–85.) “Constructive knowledge” means “[k]nowledge that one using 

reasonable care or diligence should have, and therefore that is attributed by 

law to a given person.” (Black’s Law Dict. (11th ed. 2019) p. 1043, col. 1; 

Castillo v. Toll Bros., Inc. (2011) 197 Cal.App.4th 1172, 1197.) 

Proposition 65 does not define the term “knowingly.” (See Health & 

Saf. Code, § 25249.11 [“Definitions”].) The regulations define the term as 

follows: “ ‘Knowingly’ refers only to knowledge of the fact that a discharge of,

release of, or exposure to a chemical listed pursuant to Section 25249.8(a) of 

the Act is occurring. No knowledge that the discharge, release or exposure is 

unlawful is required. However, a person in the course of doing business who, 

through misfortune or accident and without evil design, intention or 

negligence, commits an act or omits to do something which results in a 

discharge, release or exposure has not violated [Health and Safety Code] 

Section 25249.5 or 25249.6 of the Act.” (Regs., §§ 25102, subd. (n), 25600.1, 

subd. (h).) Neither Proposition 65 nor the regulations use the phrase 

“constructive knowledge” or language commonly associated with the concept, 
30

such as “should know” or “reason to know.” Nor do Proposition 65 or the 

regulations applicable to this case use the phrase “actual knowledge.”20 

The trial court provided little explanation of its determination that 

Proposition 65 requires proof of actual knowledge. In granting Amazon’s 

motion in limine to exclude evidence of constructive knowledge, the court 

cited the “statute itself” and “the nature of the Prop 65 process including the 

notice aspects.” In its statement of decision, the court stated, “Proposition 65 

and its terms apply only to ‘businesses that know they are putting one of the 

chemicals into the environment.’ (See Nicolle-Wagner v. Deukmejian (1991) 

230 Cal.App.3d 652, 659 [quoting with approval language from ballot 

argument in favor of Proposition 65].)” 

Nicolle-Wagner v. Deukmejian, supra, 230 Cal.App.3d 652 (NicolleWagner) was not concerned with the nature of the knowledge requirement in 

Proposition 65 and does not discuss any distinction between actual and 

constructive knowledge. The question in that case was whether Proposition 

65 was intended to apply to naturally occurring carcinogens and reproductive 

toxins in food. Holding it was not, the court described the statutory language 

and ballot arguments for and against Proposition 65 as indicating the 

measure “sought to regulate toxic substances which are deliberately added or 

put into the environment by human activity. . . . [¶] . . . . [T]he ballot 

argument in favor of Proposition 65 explains that ‘[Proposition 65] will not 

take anyone by surprise. [It] applies only to businesses that know they are 

putting one of the chemicals out into the environment . . . .’ (Italics in 

original.)” (Nicolle-Wagner, at p. 659.) While the emphasis on “know,” in 

20 As will be further discussed, a regulation adopted subsequent to the 

sales of the products at issue in this case refers to “actual knowledge” in 

limiting the situations in which retail sellers are required to provide 

warnings. (Regs., § 25600.2, subd. (e).)
31

context, might naturally be understood by a layperson as implying actual 

knowledge, in legal terms “ ‘knowledge’ encompasses both actual knowledge

and constructive knowledge.” (Tsasu LLC v. U.S. Bank Trust, N.A. (2021) 

62 Cal.App.5th 704, 718 (Tsasu).)21 

Lee relies heavily on a 1988 agency interpretation of the statutory 

“knowingly and intentionally” language as including constructive 

knowledge.22 “An administrative agency has the power to adopt regulations 

to effectuate the statutory purpose, provided the regulations are not in 

conflict with applicable statutes. (Woods v. Superior Court (1981) 28 Cal.3d 

21 The Tsasu court was called upon to determine whether the term 

“knowledge” in a provision of the Quiet Title Act meant solely actual 

knowledge or included constructive knowledge as well. Its first reason for 

adopting the later interpretation was that inclusion of constructive 

knowledge was “the result dictated by the statute’s plain language. 

([Citation]. [Civ. Code,] § 764.060 uses the term ‘knowledge,’ and ‘knowledge’ 

encompasses both actual knowledge and constructive knowledge. 

[Citations].)” (Tsasu, supra, 62 Cal.App.5th at p. 718.) 

22 Lee also relies on the provisions in the regulation defining 

“knowingly” that “[n]o knowledge that the discharge, release or exposure is 

unlawful is required” and “a person in the course of doing business who, 

through misfortune or accident and without evil design, intention or 

negligence, commits an act or omits to do something which results in a 

discharge, release or exposure has not violated [Health and Safety Code] 

Section 25249.5 or 25249.6 of the Act.” (Regs., §§ 25102, subd. (n), 25600.1, 

subd. (h).) Lee observes that this regulation “contemplates that ‘negligence’ 

is actionable,” but does not further explain how the definition bears on the 

question of actual versus constructive knowledge. The inference that 

constructive knowledge is sufficient if negligence is actionable makes obvious 

sense where the negligence is with respect to awareness of the presence of a 

listed chemical in a product (i.e., if the defendant, in the circumstances, 

should have known the chemical was present and remained ignorant due to 

negligence, a warning would be required). The inference seems less clear, 

however, if the negligence is in regard to exposure (e.g., selling the product). 

In any event, we do not see this point as critical to our analysis.
32

668, 679; Nicolle–Wagner, supra, 230 Cal.App.3d [at p.] 658.) We defer to the 

technical skill and expertise of the administrative agency in interpreting the 

statutes. (Ibid.)” (Mission Community Hospital v. Kizer (1993) 13 

Cal.App.4th 1683, 1691.)

The agency initially responsible for implementing Proposition 65,23 in 

its November 1988 Revised Final Statement of Reasons for what was then 

section 12601 of title 22 (now tit. 27, § 25601) of the California Code of 

Regulations, interpreted the Proposition 65 requirement that exposures be 

“knowing and intentional” before a warning is required “to include exposures 

about which there is constructive knowledge.” (OEHHA, Revised Final 

Statement of Reasons, 22 California Code of Regulations, Division 2 (Nov. 

1988), p. 39 (1988 FSOR).) 

Amazon points out that this section of the 1988 FSOR was discussing 

environmental exposures, which are distinct from consumer product 

exposures. But the agency’s statement about constructive knowledge was not 

limited to environmental exposures. While it happened to be made in a 

section discussing environmental exposures, as it was responding to a 

comment about the definition of such exposures, the “knowing and 

intentional” language applies to all exposures, not just environmental ones.24 

23 The Governor originally designated the Health and Welfare Agency 

as the “lead agency” for Proposition 65, with authority to “adopt and modify 

regulations, standards, and permits, as necessary, in order to conform with 

and implement the purposes of the initiative statute.” (Nicolle-Wagner, 

supra, 230 Cal.App.3d at p. 655.) The California Environmental Protection 

Agency’s Office of Environmental Health Hazard Assessment (OEHHA) was 

designated the lead agency for implementation of Proposition 65 in 1995. 

(Regs., § 25102, subd. (o); Health & Saf. Code, § 25249.12, subd. (a).) 

24 At the time, the regulation defined “ ‘environmental exposures’ as 

those which may foreseeably occur as the result of contact with an 

environmental medium . . . .” (1988 FSOR, supra, p. 39.) In response to a 
33

Other portions of the 1988 FSOR also discuss constructive knowledge, thus 

making clear that the agency interpretation was not limited as Amazon 

suggests.25 

concern that “requiring exposures to be foreseeable detracts from the 

requirement that exposures be knowing and intentional before a warning is 

required,” the agency explained that it interpreted the “knowing and 

intentional” requirement to include constructive knowledge and its “[u]se of 

the term ‘foreseeable’ is intended to define the limits of that constructive 

knowledge and of exposures for which businesses can reasonably be held 

responsible.” (Id. at pp. 39–40.) The current regulations do not include the 

terms “foreseeable” or “foreseeably” in the definition of “environmental

exposure,” providing simply that such exposure means “an exposure that 

occurs as the result of contact with an environmental source . . . .” (Regs., 

§ 25600.1, subd. (f).) The definition of “consumer product exposure” included 

“reasonably foreseeable use of a consumer good,” and still does. (1988 FSOR, 

p. 8; Regs., § 25600.1, subd. (e).) 

25 Regarding the statutory phrase “discharge or release into water or 

onto or into land” in Health and Safety Code section 25249.5, the agency had 

proposed a regulation regarding liability when a person in the course of doing 

business transfers a chemical to a person authorized to receive it, which a 

commentor viewed as an attempt to impose vicarious liability on a transferor 

who has no control over the transferee. (OEHHA, Final Statement of 

Reasons, 22 California Code of Regulations, Division 2, Safe Drinking Water 

and Toxic Enforcement Act of 1983 (R-48-87) § 12101 et seq. (Jan. 1988) p. 26 

<https://oehha.ca.gov/media/downloads/crnr/art13fsorjan1988.pdf> [as of 

Mar. 11, 2022]; see Regs., § 25102, subd. (f).) The agency modified the 

proposed regulation to provide that “discharge or release” to a source of 

drinking water includes transfer “for the principal purpose of disposing of the 

chemical to land or water in a manner which, if committed by the transferor 

would violate § 25249.5” and explained: “This proposal does not impose 

vicarious liability for acts over which the transferor has no control. In fact, 

this provision envisions that the transferor knows or reasonably should know

that the transferee will make an otherwise prohibited discharge, and can 

control that behavior simply by not making the transfer. Further, this 

provision does not conflict with the requirement that discharges or releases 

prohibited under the Act be committed ‘knowingly.’ The transferor would 

still have actual or constructive knowledge of the discharge of the listed 

chemical.” (1988 FSOR, p. 27; see Regs., § 25102, subd. (f), italics added.)
34

Amazon does not expressly argue the agency has disavowed the general 

interpretation of “knowingly and intentionally” as including constructive 

knowledge. Instead, it points to a regulation adopted by OEHHA in 2016 

which it says “clarif[ies] that ‘knowledge’ for downstream entities means 

actual knowledge.” As relevant here, Regulations section 25600.2, 

subdivision (e) provides: “The retail seller is responsible for providing the 

warning required by Section 25249.6 of the Act for a consumer product 

exposure only when . . . [¶] . . . [¶] [t]he retail seller has actual knowledge of 

the potential consumer product exposure requiring the warning, and there is 

no manufacturer, producer, packager, importer, supplier, or distributor of the 

product who: [¶] . . . [i]s a ‘person in the course of doing business’ under 

Section 25249.11(b) of the Act, and [¶] . . . [h]as designated an agent for 

service of process in California, or has a place of business in California.” 

(Regs., § 25600.2, subd. (e)(5), italics added.) “Actual knowledge,” for 

purposes of this regulation, means “the retail seller receives information from 

any reliable source that allows it to identify the specific product or products 

that cause the consumer product exposure. Such knowledge must be received 

by the retail seller, its authorized agent or a person whose knowledge can be 

imputed to the retail seller. (Regs., § 25600.2, subd. (f)(1).) Further, “[w]here 

the source of a retail seller’s knowledge is a notice pursuant to Section 

25249.7(d)(1) of the Act, the retail seller shall not be deemed to have actual 

knowledge of any consumer product exposure alleged in the notice until five 

business days after the retail seller receives the notice. The notice must 

provide sufficient specificity for the retail seller to readily identify the 

product or products subject to the notice, in accordance with Article 9, section 

25903(b)(2)(D).” (Regs., § 25600.2, subd. (f)(2).)
35

These regulations were adopted in furtherance of the statutory 

directive in Health and Safety Code section 25249.11, subdivision (f), that 

“[i]n order to minimize the burden on retail sellers of consumer products 

including foods, regulations implementing Section 25249.6 shall to the extent 

practicable place the obligation to provide any warning materials such as 

labels on the producer or packager rather than on the retail seller, except 

where the retail seller itself is responsible for introducing a chemical known 

to the state to cause cancer or reproductive toxicity into the consumer product 

in question.” (OEHHA, Final Statement of Reasons, Title 27, California Code 

of Regulations, Proposed Repeal of Article 6 and Adoption of New Article 6, 

Regulations for Clear and Reasonable Warnings (2016) p. 35 (2016 FSOR).)

The agency stated, “By adopting these new regulations, OEHHA 

intends to address many of the issues that have surfaced since the original 

regulations were adopted in 1988 by clarifying the relative responsibilities of 

manufacturers and others in the chain of distribution for products that are 

eventually sold at retail . . . .” (2016 FSOR, supra, p. 9.) As to retail sellers, 

the agency explained, Regulations “Section 25600.2 is based on the premises 

that (1) the consumer must receive the warnings mandated by [Health and 

Safety Code] Section 25249.6 of the Act before being exposed to a chemical 

known to cause cancer or reproductive toxicity; and (2) the primary

responsibility for providing the warning for products, including foods, is with 

the manufacturer, producer, packager, importer, or distributor of those 

products. The regulations therefore recognize that those parties are 

primarily responsible for providing warnings. This is reasonable, as 

manufacturers usually will have greater knowledge than retailers of a 

product’s chemical content and whether it causes chemical exposures that 

require a warning.” (2016 FSOR, p. 35.) 
36

Amazon, in the trial court, argued it was not a retail seller, and Lee 

therefore maintains Amazon forfeited any claim to the contrary and cannot 

rely upon the actual knowledge requirement pertaining to retail sellers. 

Amazon continues to argue it was not part of the chain of distribution at all 

and consequently was not responsible for providing Proposition 65 warnings, 

but adds that “[a]ssuming arguendo that Amazon is subject to this duty, the 

only classification that could apply is the end of the chain—i.e., the ‘retail 

seller.’ ”

The trial court found it unnecessary to determine whether Amazon is a 

retail seller or whether Regulations section 25600.2, subdivision (e), applies 

retroactively to this case (as the product sales at issue preceded the 2016 

amendments) because of the broad definition of parties required to provide 

Proposition 65 warnings (“person in the course of doing business”) and the 

fact Amazon did not claim to be a “retail seller” without responsibility for 

warnings pursuant to the 2016 regulation (Regs., § 25600.2, subd. (e)). Yet 

the court relied on the definition of “actual knowledge” in this regulation in 

finding Lee failed to establish Amazon had actual knowledge that the 

products contained mercury. 

The trial court was clearly correct to reject Amazon’s claim to be 

outside the chain of distribution. Proposition 65 imposes the duty to provide 

warnings on any “person in the course of doing business,” which 

unquestionably includes Amazon’s activities here. As the trial court 

explained, “there is no language in section 25249.l l(f) [‘definitions’ for 

Proposition 65] or the new regulations expressly limiting the duty to provide 

a Proposition 65 warning only to a ‘manufacturer, producer, packager, 

importer, supplier, or distributor of a product,’ or a ‘retail seller’ (under more 

limited circumstances described in C.C.R. § 25600.2(e)), or limiting the broad 
37

language in the operative statute imposing the warning requirement on any 

‘person in the course of doing business’ who ‘knowingly and intentionally 

expose[s] any individual’ to a listed chemical. (Health & Saf. Code § 25249.6.) 

The phrase ‘person in the course of doing business’ is broadly worded and not 

limited to parties in the chain of distribution of a product or whose status is 

defined in the regulations. (See Health & Saf. Code, § 25249.11(b).)” Amazon 

manages and oversees all aspects of third-party sales on its Web site, 

including accepting payment and providing refunds to customers on sellers’ 

behalf, providing the only channel for communication between customers and 

sellers, earning fees from sellers for each completed sale and, for sellers 

utilizing the FBA program, storing the products and arranging for their 

delivery to customers. There can be no question Amazon was, in the words of 

one court, “pivotal in bringing the product here to the consumer.” (Bolger v. 

Amazon.com (2020) 53 Cal.App.5th 431, 438 (Bolger).)

This leaves two questions regarding Amazon’s reliance on Regulations 

section 25600.2, subdivision (e): Does the regulation even apply to this case, 

in which the salient events preceded adoption of the regulation? And, if so, is 

Amazon a “retail seller” within the meaning of the regulation? 

The 2016 regulations became operative on August 30, 2018 

(<https://oehha.ca.gov/proposition-65/crnr/notice-adoption-article-6-clear-andreasonable-warnings> [as of Mar. 11, 2022]). Although the product sales at 

issue in this case predated even the date the regulations were adopted, much 

less their operative date, Amazon argues the regulations apply retroactively 

because they simply clarified existing law. Western Security Bank v. Superior 

Court (1997) 15 Cal.4th 232 (Western Security), the authority Amazon relies 

upon, explains that while “statutes do not operate retrospectively unless the 

Legislature plainly intended them to do so,” “a statute that merely clarifies, 
38

rather than changes, existing law does not operate retrospectively even if 

applied to transactions predating its enactment.” (Id. at p. 243.) 

Western Security involved a conflict between the antideficiency statute 

prohibiting judgments for any loan balance remaining after a lender’s 

nonjudicial foreclosure and the rule that the obligation of the issuer of a 

letter of credit is independent of any underlying contract between the issuer’s 

customer and the letter’s beneficiary. After a Court of Appeal ruled that the 

issuer of a letter of credit could decline to honor it after notice it would be 

used to satisfy a deficiency after a nonjudicial foreclosure sale, the 

Legislature adopted a bill expressly intended to abrogate the Court of Appeal 

decision and confirm the beneficiary’s right to rely upon both the real estate 

collateral and the letter of credit. Western Security held the new legislation 

had “no impermissible retroactive consequences” because the Legislature 

made clear it was “a clarification of the state of the law before the Court of 

Appeal’s decision,” intended to “apply to all existing loans secured by real 

property and supported by outstanding letters of credit.” (Western Security, 

supra, 15 Cal.4th at pp. 237–238.)

The “clarification” provided by Regulations section 25600.2, subdivision 

(e), is entirely different. As we have said, the regulation was adopted as a 

means of implementing the Legislature’s directive that the agency adopt 

regulations minimizing the “burden on retail sellers of consumer products” by 

“to the extent practicable plac[ing] the obligation to provide any warning 

materials such as labels on the producer or packager rather than on the retail 

seller,” except as specified. (Health & Saf. Code, § 25249.11, subd. (f); 2016 

FSOR, supra, p. 35.) Prior regulations had not addressed the allocation of 

responsibility. OEHHA described Regulations section 25600.2 as “a new, 

mandatory regulation addressing the relative responsibility of product 
39

manufacturers and others in the chain of distribution, versus the product 

retail seller.” (2016 FSOR, pp. 8–9.) The specific requirements of this new 

regulation “clarified” these relative responsibilities in the sense that they had 

not previously been spelled out, not as an expression of what had always been 

required. Given the high level of detail in the regulation—from delineation of 

the specific circumstances in which a retail seller is responsible for providing 

warnings to the definition of, and parameters for attributing, actual 

knowledge—it is impossible to view the regulation as merely clarifying the 

law that previously existed.

Moreover, OEHHA chose to make the 2016 regulations operative two 

years after they were adopted. (Gov. Code, § 11343.4, subd. (b)(2).)26 This 

two-year period is expressly addressed in regulations concerning “ ‘safe 

harbor’ ” warnings (warnings that comply with content and method of 

transmission requirements “that have been determined ‘clear and reasonable’ 

by the lead agency”). (Regs., § 25600, subds. (a) & (b).) Subdivision (b) of 

section 25600 of the Regulations provides that a warning for a consumer 

product manufactured prior to August 30, 2018, is “deemed to be clear and 

reasonable if it complies with” the prior regulation. The 2016 FSOR 

explained that the two-year implemental period was intended to “avoid the 

difficulties and expense involved for manufacturers and retail sellers to locate 

all products bearing the old warnings.” (2016 FSOR, supra, pp. 13–14.) The 

delayed effective date applied to all the 2016 regulations, and is clearly 

26 With specified exceptions, a regulation required to be filed with the 

Secretary of State becomes effective on the quarterly basis established in 

Government Code section 11343.4, subdivision (a). One of the exceptions is 

where “[a] later date is prescribed by the state agency in a written 

instrument filed with, or as part of, the regulation . . . .” (Gov. Code, 

§ 11343.4, subd. (b)(2).) 
40

inconsistent with any intent that the new regulations be applied 

retrospectively.

Amazon, therefore, cannot rely on Regulations section 25600.2, 

subdivision (e), to support the trial court’s determination that Lee was 

required to prove actual knowledge. 

Nor does Regulations section 25600.2 indicate Proposition 65, in 

general, contains an actual knowledge requirement. In fact, the introduction 

of an express “actual knowledge” requirement for retail sellers in the 2016 

regulation is itself an indication that actual knowledge was not previously 

required to trigger the obligation to provide Proposition 65 warnings. By 

specifying that retail sellers are responsible for providing warnings only if 

they have actual knowledge of the potential consumer exposure (and no 

upstream entity can readily be compelled to provide the warning), 

Regulations section 25600.2, subdivision (e)(5), implicitly indicates there are 

circumstances in which constructive knowledge is sufficient to require 

provision of a warning. It is a familiar rule of statutory interpretation that 

“[a] construction making some words surplusage is to be avoided.” (DynaMed, Inc. v. Fair Employment & Housing Com. (1987) 43 Cal.3d 1379, 1387.) 

The same rules of construction apply to initiative measures. (Williams v. 

Superior Court (2001) 92 Cal.App.4th 612, 622.) If OEHHD viewed all 

references to knowledge in the Proposition 65 regulations as meaning actual 

knowledge, it would not have needed to include an express “actual” 

knowledge requirement in Regulations section 25600.2, subdivision (e). The 

purpose of this regulation was to distinguish retail sellers’ obligations from 

those of entities higher on the chain of distribution. One of the ways it does 

so is by requiring “actual knowledge” where the statutory phrase “knowingly” 
41

would otherwise connote—and had been interpreted as including—actual or

constructive knowledge.

The critical question, of course, is whether the electorate intended 

“knowingly and intentionally” to mean solely actual knowledge or 

constructive knowledge as well. As we have said, because Proposition 65 is “a 

remedial law, designed to protect the public,” we construe its provisions 

“broadly to accomplish that protective purpose.” (People ex rel. Lungren v. 

Superior Court, supra, 14 Cal.4th at p. 314; Center for Self-Improvement & 

Community Development v. Lennar Corp., supra, 173 Cal.App.4th at 

pp. 1550–1551.) 

The preamble to Proposition 65, section 1 of the law proposed to the 

voters, makes clear the measure was driven by the voters’ desire for greater 

protection against hazardous chemicals, specifically including information 

about exposures, strict enforcement and deterrence of actions threatening 

public health and safety. The preamble states: “The people of California find 

that hazardous chemicals pose a serious potential threat to their health and 

well-being, that state government agencies have failed to provide them with 

adequate protection, and that these failures have been serious enough to lead 

to investigations by federal agencies of the administration of California’s 

toxic protection programs. The people therefore declare their rights: [¶] (a)

To protect themselves and the water they drink against chemicals that cause 

cancer, birth defects, or other reproductive harm. [¶] (b) To be informed 

about exposures to chemicals that cause cancer, birth defects, or other 

reproductive harm. [¶] (c) To secure strict enforcement of the laws controlling 

hazardous chemicals and deter actions that threaten public health and safety.

[¶] (d) To shift the cost of hazardous waste cleanups more onto offenders and 

less onto law-abiding taxpayers. [¶] The people hereby enact the provisions 
42

of this initiative in furtherance of these rights.” (Ballot Pamp., Gen. Elec. 

(Nov. 4, 1986) text of Proposition 65, p. 53, italics added.) (Hereafter Ballot 

Pamp.)

The public policy reflected in these findings and stated purposes 

militates in favor of an interpretation of the “knowingly and intentionally” 

requirement of Health and Safety Code section 25249.6 as including 

constructive knowledge. (See Tsasu, supra, 62 Cal.App.5th at p. 719 

[“defining ‘knowledge’ in [quiet title statute] to encompass both actual and 

constructive knowledge is the result dictated by public policy”].) Interpreting 

section 25249.6 to require warnings only when a person in the course of doing 

business has actual knowledge that he or she will expose any individual to a 

listed chemical would significantly limit the reach of the statute and create 

incentives to avoid information that might reveal potential sources of 

exposure. 

Tsasu offers an illustration, albeit in a different context. Pursuant to 

the statute at issue in that case, a third party acting in reliance on a quiet 

title judgment retains its property rights, even if that judgment is 

subsequently invalidated as void, if the third party “qualifies as a ‘purchaser 

or encumbrancer for value . . . without knowledge of any defects or 

irregularities in [the earlier quiet title] judgment or the proceedings.’ ([Code 

Civ. Proc.,] § 764.060.)” (Tsasu, supra, 62 Cal.App.5th at pp. 716–717.) 

Among its reasons for construing “knowledge” in the statute as including 

both actual and constructive knowledge, the Tsasu court explained that 

limiting “knowledge” to actual knowledge “creates wholly perverse incentives 

because it discourages prospective buyers from checking the record of title or 

from heeding ‘warning signs’ necessitating further inquiry—lest they acquire 

actual knowledge of a defect or irregularity with a quiet title judgment that 
43

would strip them of section 764.060’s protection. Such incentives are inimical 

to the entire system of real property law in California, which places upon real 

estate buyers a duty to inquire into the validity of their prospective 

ownership claim [citation], and to heed—not ignore—any ‘ “reasonable 

warning signs” ’ [citations].” (Id. at pp. 719–720.) The court declined to 

interpret the statute as limited to actual knowledge, in part, because the 

statute was not intended to “encourage recklessness or willful ignorance.” 

(Id. at p. 720.)

In the context of Proposition 65, limiting the obligation to provide 

warnings to actual knowledge would create incentives for businesses to avoid 

information that might alert them to the presence of hazardous chemicals 

and potential for exposures. This result would be inimical to the protective 

purpose of the law generally, and specifically to the voters’ stated purposes of 

furthering the dissemination of information about exposures to toxic 

chemicals, strict enforcement of laws controlling hazardous chemicals and 

deterrence of actions that threaten public health and safety. (Ballot Pamp., 

supra, p. 53.)

Amazon argues the trial court’s interpretation of Health and Safety 

Code section 25249.6 as requiring actual knowledge is supported by cases 

“confirm[ing] that a duty to disclose a fact cannot arise without actual 

knowledge of the fact.” The cases it relies upon, however, are not particularly 

helpful. In San Diego Hospice v. County of San Diego (1995) 31 Cal.App.4th 

1048, the plaintiff sought recission of a release on a theory of fraudulent 

nondisclosure of facts the defendant of which the defendant allegedly had 

imputed knowledge. (Id. at p. 1055.) The court explained that in order to

establish the duty to disclose underlying the claim, the plaintiff must show 

“the material fact is known to (or accessible only to) the defendant” and “the 
44

defendant knows the plaintiff is unaware of the fact and cannot reasonably 

discover the undisclosed fact.” (Ibid.) Because the duty to disclose “requires 

some element of scienter—knowledge of the other party’s ignorance,” it could 

not arise if the material facts were not “actually known” to the defendant: 

“We cannot perceive how it is possible for a principal to know the other party 

is ignorant of something of which the principal is equally ignorant.” (Id. at 

pp. 1055–1056.) This reasoning, specific to the scienter element of the tort 

claim at issue, has no bearing on the meaning of the knowledge requirement 

in a statute requiring warnings of potential exposures to hazardous 

chemicals.

The other case Amazon cites is no more apt. Santiago v. Firestone Tire 

& Rubber Co. (1990) 224 Cal.App.3d 1318 involved employees’ claims under 

Labor Code section 3602, subdivision (b), which provides an exception to the 

general rule that workers’ compensation is the sole and exclusive remedy for 

injured workers, permitting an action for damages against the employer 

where the employee’s injury is aggravated by the employer’s “ ‘fraudulent 

concealment of the existence of the injury and its connection with the 

employment.’ ” (Santiago. at p. 1323.) Santiago held the employees were 

required to show the employer had actual knowledge of the employees’ 

injuries and fact they were caused by their employment, rejecting the 

argument that constructive knowledge should apply based on a detailed 

analysis of the “history of Labor Code section 3602, the language of the 

statute, and the cases construing it.” (Id. at pp. 1331–1334.) Amazon quotes 

the Santiago court’s statement that “ ‘defendant obviously could not be 

charged with concealing matters which it did not know.’ ” (Id. at p. 1334.) 

But the issue in the present case is not concealment of facts, and the holding

that fraudulent concealment necessarily requires actual knowledge says
45

nothing about the statutory meaning of “knowingly” with respect to the 

obligation to provide warnings of potential exposures under Proposition 65. 

There is nothing rationally or logically inconsistent with a requirement that a 

business provide warnings—or be liable for failure to do so—if it knows or 

has sufficient reason to know it is exposing “any individual” to a listed toxic 

chemical. 

Amazon finds support for its argument that Health and Safety Code 

section 25249.6 requires actual knowledge in the fact that this provision uses 

the phrase “knowingly and intentionally” while section 25249.5, which 

prohibits discharge of chemicals into water, uses only “knowingly.” Relying 

on the rules of statutory interpretation that instruct us to, if possible, give 

significance to every word and avoid a construction that renders some words 

surplusage (Moyer v. Workmen’s Comp. Appeals Bd. (1973) 10 Cal.3d 222, 

230), Amazon argues we cannot ignore the inclusion of “intentionally” in 

Health and Safety Code section 25249.6. With this much, we agree. But we 

do not agree with Amazon’s conclusion that the phrase “knowingly and 

intentionally” “imposes a higher level of knowledge” than the word 

“knowingly” alone. 

As we have said, neither Proposition 65 nor the regulations define 

“intentionally.” “ ‘ “When a term goes undefined in a statute, we give the

term its ordinary meaning.’ ” (De Vries v. Regents of University of California

(2016) 6 Cal.App.5th 574, 590–591.) ‘In divining a term’s “ordinary

meaning,” courts regularly turn to general and legal dictionaries.’ (Id. at 

p. 591; People v. Hodges (1999) 70 Cal.App.4th 1348, 1355.)” (Upshaw v. 

Superior Court (2018) 22 Cal.App.5th 489, 504.)

There is overlap in dictionary definitions of the terms “knowingly” and 

“intentionally”; definitions of the former sometimes refer to the latter and 
46

each is considered a synonym of the other.27 But definitions of “knowingly” 

tend to focus on awareness28 while definitions of “intentionally” tend to focus 

on purpose.29

27 For example, the Oxford English Dictionary (3d ed. 2015) (OED) 

includes “intentionally” in its definition of “knowingly” (OED Online 

<https://oed.com/view/Entry/104167?redirectedFrom=knowingly#eid> [as of 

Mar. 11, 2022]); Merriam-Webster’s Thesaurus lists “intentionally” and 

“knowingly as synonyms for each other. (Merriam-Webster’s Thesaurus 

Online <https://www.merriam-webster.com/thesaurus/intentionally> [as of 

Mar. 11, 2022]; <https://www.merriam-webster.com/thesaurus/knowingly> 

[as of Mar. 11, 2022].) 

28 For example, “knowingly” is defined by the OED as “[w]ith 

knowledge or awareness (of what one is doing, of a fact, etc.); consciously, 

intentionally.” (OED Online 

<https://www.oed.com/view/Entry/104167?redirectedFrom=knowingly#eid> 

[as of Mar. 11, 2022]) and by Merriam-Webster Unabridged Dictionary 

(Merriam-Webster) as “with awareness, deliberateness, or intention” 

(Merriam-Webster Dict. Online <https://unabridged.merriamwebster.com/unabridged/knowingly> [as of Mar. 11, 2022]). Black’s Law 

Dictionary defines “knowing” as “[h]aving or showing awareness or 

understanding; well-informed” and “[d]eliberate; conscious,” and “knowingly” 

as “[i]n such a manner that the actor engaged in prohibited conduct with the 

knowledge that the social harm that the law was designed to prevent was 

practically certain to result; deliberately.” It explains: “A person who acts 

purposely wants to cause the social harm, while a person who acts knowingly

understands that the social harm will almost certainly be a consequence of 

the action, but acts with other motives and does not care whether the social 

harm occurs.” (Black’s Law Dict. supra, p. 1042, col. 2.) 

29 Examples include “with intention, on purpose” (OED Online 

<https://www.oed.com/view/Entry/97497?redirectedFrom=intentionally#eid> 

[as of Mar. 11, 2022]) and “in an intentional manner: with intention: 

purposely” (Merriam-Webster Dict. Online <https://unabridged.merriamwebster.com/unabridged/intentionally> [as of Mar. 11, 2022). Black’s Law 

Dictionary, supra, page 965, defines “intentional” as “[d]one with the aim of 

carrying out the act.” 
47

To give significance to each word used in Health and Safety Code 

section 25249.6, it is more reasonable to view “intentionally” as adding this 

concept of purpose than as giving “knowingly” a different meaning than it 

would have when used on its own. We see no basis for reading “intentionally” 

in section 25249.6 as essentially modifying “knowingly” to require a higher 

level of knowledge than “knowingly” would otherwise convey. As we have 

said, an actual knowledge requirement would narrow the scope of section 

25249.6, contrary to the purpose of Proposition 65. (See California 

Manufacturers & Technology Assn. v. State Water Resources Control Bd. 

(2021) 64 Cal.App.5th 266, 281–282 [statutory term with alternative 

definitions construed as intended to carry the meaning more consistent with 

legislative purpose].) The inclusion of “intentionally” in this statute, as 

opposed to section 25249.5, is an insufficient basis for the interpretation 

Amazon seeks.30

Finally, Amazon points to the absence in Proposition 65 of language 

often used to indicate a statute contemplates constructive knowledge. (E.g., 

30 One explanation for the distinction in language between these two 

statutes might lie in the different degree of regulation each provides. Health 

and Safety Code section 25249.5 is an outright prohibition against 

contamination of drinking water. In prohibiting businesses from “knowingly” 

discharging or releasing listed chemicals into water or land where they 

probably will pass into a source of drinking water, this statute appears to 

contemplate liability when the business is aware that the discharge or 

release it causes contains the listed toxin and is likely to reach a source of 

drinking water, regardless of whether it intends this result. Health and 

Safety Code section 25249.5 is less restrictive, requiring warnings but not 

prohibiting the act that causes exposure to the chemical. In keeping with 

this lower level of regulation, the statutory requirement is triggered only 

where the defendant is not only aware but also intends to take the action that 

results in the exposure—in the case of a consumer product, intends to take 

the action that moves the product toward the consumer.
48

Labor Code, § 2810 [“A person or entity shall not enter into a contract or 

agreement for labor or services . . . where the person or entity knows or 

should know that the contract or agreement does not include funds sufficient 

to allow the contractor to comply with all applicable . . . laws . . .”]; Civ. Code, 

§ 3426.1 [“ ‘Misappropriation’ means: [¶] (1) Acquisition of a trade secret of 

another by a person who knows or has reason to know that the trade secret 

was acquired by improper means”].) While the presence of such language 

may compel a conclusion that the statute encompasses constructive 

knowledge, its absence is not dispositive. (E.g., PacifiCare Life & Health Ins. 

Co. v. Jones (2018) 27 Cal.App.5th 391, 417–418 [upholding regulation 

defining “knowingly,” in statute delineating unfair and deceptive insurance 

business practices, as including constructive knowledge]; Tsasu, supra, 

62 Cal.App.5th at pp. 717–721 [construing “knowledge” in quiet title statute 

as including constructive knowledge].)

We conclude the trial court erred in ruling that Lee was required to 

prove Amazon had actual knowledge the products at issue contained mercury 

and excluding evidence of constructive knowledge. Of course, this error 

would be of no consequence if Lee is correct that the record demonstrates 

substantial evidence of actual knowledge as a matter of law. Lee argues 

Amazon had actual knowledge of the mercury in the Faiza and Face Fresh 

skin-whitening creams from the RAPEX notices and for the Monsepa cream 

from Lee’s notice of violation. He does not contend Amazon had actual 

knowledge as to the Meiyong products.

Lee’s argument is strongest with respect to the Monsepa cream. Lee 

asserts that a notice of violation necessarily establishes actual knowledge, 

citing the definition of Regulations section 25600.2, subdivision (f)(2), which 

expressly treats a notice of violation as a source of a retail seller’s actual 
49

knowledge.31 As we have said, Regulations section 25600.2 is not applicable 

to the present case. But “[p]roof of actual knowledge focuses on what 

information a defendant must have been aware of” (People v. ConAgra 

Grocery Products Co., supra, 17 Cal.App.5th at pp. 84–85), and the notice of 

violation was directly served on Amazon. 

Amazon does not dispute the general proposition that a notice of 

violation establishes actual knowledge, but it argues the notice in the present 

case was insufficient to do so. The notice of violation named Amazon and 

aztopselstore.com (the distributor of Monsepa cream) as violators, specified 

the chemical (“Mercury”), routes of exposure (“Ingestion, Dermal, Inhalation”) 

and type of harm (“Developmental Toxin”), and identified the products as 

“[s]kin-lightening creams” with “Monsepa Express Peeling Night Face 

Cream, 15 mL size” as an example. Amazon argues the reference to “[s]kinlightening creams” did not provide notice as to any specific product, and the 

CDPH’s investigation, which found mercury in only seven of over a hundred 

skin-lightening creams tested, demonstrated most such creams do not contain 

mercury. Amazon further argues the fact that the notice of violation named 

“Monsepa Express Peeling Night Cream” was insufficient to establish 

knowledge because the product Lee had tested for this litigation has a 

31 The regulation states that “ ‘[a]ctual knowledge’ means the retail 

seller receives information from any reliable source that allows it to identify 

the specific product or products that cause the consumer product exposure” 

and “[w]here the source of a retail seller’s knowledge is a notice pursuant to 

[Health and Safety Code] Section 25249.7(d)(1) of the Act, the retail seller 

shall not be deemed to have actual knowledge of any consumer product 

exposure alleged in the notice until five business days after the retail seller 

receives the notice. The notice must provide sufficient specificity for the 

retail seller to readily identify the product or products subject to the notice, in 

accordance with Article 9, section 25903(b)(2)(D).” (Regs., § 25600.2, 

subd. (f)(1), (2).)
50

different name (“Monsepa Express Peeling” per packaging; “Monsepa Express 

Peeling Remove Dark Spots Face Cream” on Amazon listing).

Amazon’s argument is not persuasive. As Lee points out, the 

regulations require a notice of violation to provide “the name of the consumer 

product or service, or the specific type of consumer product or services, that 

cause the violation, with sufficient specificity to inform the recipients of the 

nature of the items allegedly sold in violation of the law and to distinguish 

those products or services from others sold or offered by the alleged violator 

for which no violation is alleged.” (Regs., § 25903, subd. (b)(2)(D).) OEHHA 

has explained that this regulation is meant to avoid identification of the 

products at issue in “very broad terms, such as ‘various aerosol, paint, 

adhesive and/or automotive products, including but not limited to,’ ” that are 

“inadequate to describe the nature of the violation that is claimed.” 

(OEHHA, Final Statement of Reasons, Adopt Section 12908, Notices of 

Violation, title 22, Division 2, California Code of Regulations, p. 10.) On the 

other hand, the agency stated, “[c]learly it would be sufficient simply to say 

‘aerosol spray paint,’ ‘car wax’ or ‘paint thinner.’ Such a description would at 

least identify the category of products that will be the subject of the action, 

and would enable the public agency to focus the investigation.” (Ibid.)

Lee’s notice of violation satisfied these parameters. The notice of 

violation informed Amazon that a category of products—“skin-lightening 

creams”—allegedly caused exposure to mercury and specifically named one 

such product. Although the product Lee had tested was identified with a 

slightly different name on the Amazon Web site, the notice, Web site listing,

and product packaging all used the distinctive “Monsepa Express Peeling”

identifier. In our view, this constituted notice that the Monsepa skin-
51

lightening cream Lee put at issue here was alleged to contain mercury and, 

thus, was evidence of actual knowledge. 

In arguing Amazon had actual knowledge that the Faiza and Face 

Fresh creams contained mercury from the RAPEX notices for these products, 

Lee relies on Kosnoff’s testimony that Amazon employees in Europe review 

RAPEX notices; Amazon would have been aware of the 2013 RAPEX notice 

for Faiza Beauty Cream; and he was aware a “very similar” product was 

listed on the American Web site. This testimony is less definitive proof of 

actual knowledge than the evidence regarding the Monsepa cream: Kosnoff 

described a general business practice that would be expected to result in 

Amazon’s awareness of the RAPEX notices, but his testimony also raised

questions about the relationship between and management of Amazon’s 

European and American Web sites which are not addressed by any evidence 

in the record. The RAPEX notices may well provide persuasive evidence of 

constructive knowledge, but we cannot find them sufficient to establish 

actual knowledge as a matter of law so as to overturn the trial court’s finding 

of no actual knowledge.

Because the trial court precluded evidence of constructive knowledge, 

we have no means of evaluating whether Lee will be able to make a showing 

sufficient to alter the ultimate outcome of this case.32 Evidence of 

32 In finding Amazon did not have actual knowledge that the skinlightening creams contained mercury, the trial court noted that mercury was 

not identified as an ingredient on the packaging or product detail pages. Lee 

argues the absence of information on a product’s label cannot be the basis for 

finding an absence of actual knowledge, an argument also maintained by the 

Attorney General in his amicus brief; otherwise, Amazon could avoid liability 

even if it was informed by the third-party seller or any other reliable source 

that the product contained mercury. We do not read the trial court as having 

held the absence of information on the products’ packaging or product detail 

pages was dispositive of the actual knowledge issue; the court went on to say 
52

constructive knowledge must be evaluated in the context of all relevant 

circumstances bearing on what Amazon had reason to know or reasonably 

should have known. This will presumably include facts related to Amazon’s 

business operations and role in bringing the products to customers as well as 

the statutory context. 

With regard to the latter, Health and Safety Code section 25249.11, 

subdivision (f), makes clear that the Legislature did not intend all parties 

involved in bringing a consumer product into the hands of the consumer to

bear the same responsibility for providing the warnings required by 

Proposition 65 and, specifically, intended to minimize the burden on retail 

sellers in most cases. Amazon’s assertion that it is not a retail seller is part 

of its broader argument that it is not a part of the chain of distribution at all, 

and therefore not subject to section 25249.6. As we have said, this broader 

argument unsustainable. But Amazon’s fallback position—that if it is part of 

the chain of distribution, the only thing it can be considered is a retail 

seller—is not unreasonable. There is no evidence to support characterizing 

Amazon as a manufacturer, producer, packager, importer, or distributor of 

the products at issue. Regardless of whether it comes within ordinary 

definitions of “retail seller” or can be considered a “seller” if it does not take 

title of the product in question (see Milo & Gabby LLC v. Amazon.com, Inc. 

(Fed. Cir. 2017) 693 Fed. Appx. 879, 890 [Amazon not a “seller” for purposes 

of copyright infringement claim]), Amazon’s role in the present case was 

that Lee failed to establish Amazon had actual knowledge “at any earlier 

time,” perhaps a reference to evidence such as the RAPEX notices and CDPH 

notice. It should be obvious that while packaging indicating a listed toxin is 

an ingredient would supply actual knowledge, absence of such information on 

product labeling, in and of itself, is far too limited a basis for finding an 

absence of knowledge, actual or otherwise.
53

analogous to a retail seller’s for purposes of Health and Safety Code section 

25249.6 in that Amazon had nothing to do with determining the contents, 

manufacturing or labelling of the skin-lightening products. As OEHHA noted

regarding the 2016 regulations, entities such as manufacturers, producers 

and packagers “usually will have greater knowledge than retailers of a 

product’s chemical content and whether it causes chemical exposures that 

require a warning.” (2016 FSOR, supra, p. 35.) Still, Amazon made the 

products available for purchase by the ultimate consumer and, at a 

minimum, facilitated the sale by providing a forum for it to take place, 

handling the finances of the transaction and controlling communications 

between the customer and the third-party sellers. All these facts may be

relevant considerations with respect to what knowledge can be attributed to 

Amazon.

III.

The trial court found Lee failed to prove that Amazon exposed 

consumers to mercury because he did not prove anyone actually used the 

skin-lightening products at issue. The trial court noted that Lee “did not 

present any evidence of exposure related to any of the product purchasers, 

despite obtaining those purchasers’ contact information from Amazon during 

discovery”; the evidence established “there has been a public campaign to 

discourage the use of skin-lightening creams that may contain mercury, 

including a buy-back program for new and used products”; and “[t]here was 

no evidence that anyone was exposed to mercury in connection with any of 

the four units that were actually purchased by plaintiff’s counsel through 

Amazon’s marketplace.” 

Lee maintains the trial court’s interpretation of “expose” improperly 

narrowed the scope of Proposition 65, imposing a burden that would make it 
54

all but impossible to enforce the law with respect to consumer products due to 

the expense of obtaining evidence that more than a minimal number of 

people opened and used a product they purchased. Lee points out that 

consumer products may be sold to millions of customers, many of whom may 

remain anonymous if the products were purchased in stores that do not keep 

records of individual purchasers or, if identifiable, may be unwilling to

participate in litigation. 

Moreover, Lee argues, proof of individual consumers’ use of the 

products is unnecessary because common sense dictates a conclusion that 

people purchase products in order to use them. Lee and the Attorney General 

both point to the statutory maxim that “[t]hings happen according to the 

ordinary course of nature and the ordinary habits of life.” (Civ. Code, § 3546.) 

Thus, the Attorney General, drawing on his experience in enforcing 

Proposition 65, states he “always assumed that people who buy cookies eat 

them; people who buy sodas drink them; and people who buy skin creams 

apply them to their skin.” The Attorney General states, “companies do not 

sell products that their customers will not use, and consumers do not buy 

skin creams unless they intend to apply them to their skin. Accordingly, in 

his cases, the Attorney General has not provided declarations from 

consumers that they ate the lead-containing cookies, took the vitamins, or 

used the anti-diarrheal medicine that have been the subject of his Proposition 

65 claims” and no court has “ever even suggested that such evidence was 

necessary.” Indeed, as Lee points out, when Lee sought a preliminary 

injunction in this case, one of Amazon’s arguments in opposition was that the 

request was made two years after the complaint was filed and, “[b]ecause 

Amazon blocked the sale of the relevant Products long ago, the only 
55

reasonable inference is that the Products have been completely used since 

they were last purchased.” 

The Proposition 65 regulations define “expose” as meaning “to cause to 

ingest, inhale, contact via body surfaces or otherwise come into contact with a 

listed chemical. An individual may come into contact with a listed chemical 

through water, air, food, consumer products and any other environmental 

exposure as well as occupational exposures.” (Regs., § 25102, subd. (i).) In 

article 6, “Clear and Reasonable Warnings,” “[c]onsumer product exposure” is 

defined as “an exposure that results from a person’s acquisition, purchase, 

storage, consumption, or any reasonably foreseeable use of a consumer 

product, including consumption of a food. (Regs., § 25600.1, subd. (e).) When 

this regulation was adopted in 2016, OEHHA’s FSOR included the statement, 

“If a person’s use of a product is ‘reasonably foreseeable’ even if it is not 

entirely consistent with label recommendations, any resulting exposures to 

listed chemicals can properly be considered to be ‘knowing and intentional’ on 

the part of the product manufacturer, and are therefore subject to Proposition 

65.” (2016 FSOR, supra, p. 31.) 

The trial court viewed the definition of “consumer product exposure” as 

requiring proof of an “actual ‘exposure’ ” and the agency’s explanatory 

statement as confirming that “foreseeability may impact knowledge and 

intent, but it does not eliminate the requirement of exposure.” In our view, 

however, the regulatory definition of “consumer product exposure” provides 

less insight into the meaning of “expose” as used in Health and Safety Code 

section 25249.6 than the trial court attributed to it. The explanatory 

statement the trial court noted was in response to a comment seeking to alter 

the definition of “consumer product exposure” by replacing the phrase “any 

reasonably foreseeable use of a product” with “use of a product in accordance 
56

with recommendations made in the product’s labels or labeling or with other 

actual and accepted uses of the product” or “use of the product in accordance 

with the product labeling recommendations or ordinary conditions of use.” 

(2016 FSOR, supra, p. 31.) OEHHA rejected the proposed revision because it 

would “unnecessarily limit the potential exposure scenarios to listed 

chemicals” and “[l]imiting the scope of the definition would not be consistent 

with the Act.” (Ibid.) The foreseeability issue addressed in the agency’s 

statement pertained only to the “use” component of the provision defining 

“consumer product exposure,” serving to limit the extent to which a business 

subject to Proposition 65 is required to anticipate the ways its product might 

be used. No such clarification was necessary for the other sources of exposure 

listed in the regulation (purchase, acquisition, storage). 

The regulation defines “consumer product exposure” by describing the 

sources from which an exposure can result, but it does not define what 

“exposure” actually consists of. The phrase “consumer product exposure” 

appears in article 6 of the Act (“Clear and Reasonable Warnings”), in 

regulations describing the required contents of Proposition 65 warnings and 

methods by which they may be provided. (Regs., §§ 25601, 25602, 25603.) 

Regulations section 25600, subdivision (a), provides that “[n]othing in Article 

6 shall be interpreted to determine whether a warning is required for a given 

exposure under Section 25249.6 of the Act.” The original lead agency also 

distinguished between the definition of “consumer product exposure” and the 

definition of “expose” for purposes of Health and Safety Code section 25249.6. 

Responding to a comment that “consumer exposures are triggered by the 

purchase of a product, rather than by consumption,” the agency stated: “The 

definition of ‘consumer products exposure,’ however, is not intended to 

establish when an exposure occurs.· It is intended to address the availability 
57

of the ‘safe harbor’ warning. The term ‘expose’ is defined elsewhere as 

meaning ‘to cause to ingest, inhale, contact via body surfaces or otherwise 

come into contact with a chemical.’ ” (Former Cal. Code Regs., tit. 22,

§ 12201, subd. (f) [now tit. 27, § 25102, subd. (i)].) “This could include the 

purchase by an individual of a product, not just the consumption of that 

product.” (1988 FSOR, supra, p. 10.)33

33 Arguing that this agency explanation “does not establish that an 

exposure necessarily occurs only from a purchase,” Amazon points to 

statements in the 2016 FSOR which it says explain that “a person who 

purchases a product is not necessarily exposed” and “[i]n some cases, 

exposure will not occur until the product packaging is opened.” 

The first of these statements (italicized below) is part of a comment 

submitted to OEHHA regarding its proposed regulation defining “retail 

seller” (Regs., § 25600, subd. (l)): “In the definition for ‘retail seller,’ the term, 

‘purchasers’ should be changed to ‘consumers,’ both for consistency and to 

avoid inadvertently including wholesale distributors. Often, the consumer of 

the product, and thus the individual who is exposed, is not the purchaser.” 

(2016 FSOR, supra, p. 33.) OEHHA responded that it agreed and had 

replaced the term “purchasers” with “consumers.” (Ibid.) Read in context, it 

is apparent that the point was to avoid language that might be taken as 

extending the regulation restricting circumstances in which retail sellers are 

required to provide Proposition 65 warnings to sellers that do not sell directly 

to consumers, not to suggest that sale to a consumer does not expose the 

consumer to a listed chemical in the product. 

The second statement (italicized below) is from the OEHHA’s response 

to a comment that a proposed regulation specifying methods for providing 

safe harbor consumer product exposure warnings (Regs., § 25602, subd. (a)) 

was unclear as to “whether a warning is required on both the immediate 

container and the outer packaging of a product.” (2016 FSOR, supra, p. 87.) 

OEHHA responded in the negative, explained that the regulations provided 

several options for warnings, then stated, “[t]he warning should be placed in 

such a manner as to ensure that it is seen and understood prior to exposure. 

For example, . . . if a person will be exposed to a listed chemical immediately 

upon opening a product’s outer packaging through contact with the product, 

the warning should be placed on the outer container or wrapper.” (Ibid.) This 

guidance is obviously directed at those in a position to provide warnings on 
58

Lee’s claim in the present case is that Amazon violated the requirement 

of Health and Safety Code section 25249.6 that a business shall not 

knowingly and intentionally “expose” any individual to a listed chemical 

without first providing clear and reasonable warning. The ordinary 

definition of “expose” is “[t]o lay open (to danger, ridicule, censure, etc.).” 

(OED, “expose” OED Online 

<https://www.oed.com/search?searchType=dictionary&q=expose&_searchBtn

=Search> [as of Mar. 11, 2022]; Merriam-Webster Dict. Online, “expose” [“to 

lay open (as to attack, danger, trial, or test)”] <https://unabridged.merriamwebster.com/unabridged/expose> [as of Mar. 11, 2022].) The original lead 

agency expressly relied upon this general definition of “expose” in explaining

the rule it adopted for calculating whether a business employs 10 or fewer 

employees (and therefore is not subject to the requirements of Proposition 

65). (1988 FSOR, supra, pp. 19, 26

<https://oehha.ca.gov/media/downloads/crnr/art13fsorjan1988.pdf> [as of 

Mar. 11, 2022].) The rule requires counting all full- and part-time employees 

“on the date on which the discharge, release or exposure occurs.” (Former 

Cal. Code Regs., tit. 22, § 12102; now tit. 27, § 25102, subd. (h).) Discussing 

the rule in the context of exposure to agricultural products, the agency 

rejected the assumption that exposure occurs on the date the product is 

consumed: “In fact, nothing provides that exposure occurs only at the time a 

particular consumer good is consumed. The term ‘expose’ generally means ‘to 

lay open,’ as to something which is injurious or dangerous. Laying an 

individual open to a chemical hazard through a consumer product could 

products and their packaging, such as manufacturers and packagers, to 

ensure such warnings are not placed where they may be overlooked by the 

consumer. It does not address the meaning of “expose” with respect to a 

business that sells a product to the consumer.
59

result from any act which propels the product toward the individual.” (1988 

FSOR, p. 19.)

This interpretation makes clear that the original lead agency 

understood its definition of “expose” to refer to any act that brings the 

product containing a listed chemical into contact with an individual, 

regardless of the individual’s actual use. “Expose,” in other words, refers to 

potential exposure as well as realized exposure. The regulatory definition of 

“expose” has not changed in any meaningful way, and we are not aware of 

any departure from the lead agency’s original interpretation. That 

interpretation is consistent with the statutory requirement that Proposition 

65 warnings be provided before an individual is exposed to a listed chemical. 

(Health & Saf. Code, § 25249.6.) Necessarily, consumer product exposure 

warnings must be provided prior to or concurrent with sale to the retail 

consumer; once the product has reached the consumer, the seller, 

manufacturer or other party in the chain of distribution would have no means 

of providing a warning. The regulations’ safe harbor warning requirements 

for consumer products specify that the warning must be provided by one or 

more of four means, all of which entail visibility to the consumer prior to or 

during a purchase;34 for Internet purchases, warnings must be provided prior 

to completion of the purchase. (Regs., § 25602, subds. (a) & (b).) 

34 These means are: “A product-specific warning provided on a posted 

sign, shelf tag, or shelf sign, for the consumer product at each point of display 

of the product”; “A product-specific warning provided via any electronic device 

or process that automatically provides the warning to the purchaser prior to 

or during the purchase of the consumer product, without requiring the 

purchaser to seek out the warning”; “A warning on the label that complies 

with the content requirements in Section 25603(a)”; and/or “A short-form 

warning on the label that complies with the content requirements in Section 

25603(b)” and is in a specified type size. (Regs., § 25602, subd. (a)(2)-(4).)
60

Interpreting “expose” by its ordinary meaning is also consistent with 

Proposition 65’s protective purpose. As we have said, the preamble to 

Proposition 65 expressly invoked the voters’ “rights” to “be informed about 

exposures to chemicals that cause cancer, birth defects, or other reproductive 

harm[,]” and to “secure strict enforcement of the laws controlling hazardous 

chemicals and deter actions that threaten public health and safety.” (Ballot 

Pamp., supra, p. 53.) Proposition 65 is not primarily about punishment for 

harm that has been inflicted; it is about protection from harmful chemicals, 

the ability to make informed choices about coming into contact with such 

chemicals, and deterrence of conduct that undermines these purposes. The 

interpretation of Health and Safety Code section 25249.6 advanced by 

Amazon and adopted by the trial court would absolve a business that 

knowingly and intentionally, without warnings, sold a product whose 

intended use would necessarily cause the consumer to ingest, inhale or 

otherwise come into bodily contact with a listed chemical, if the consumer 

happened not to use the product he or she purchased. This cannot be what 

the voters who enacted Proposition 65 intended. 

The trial court cited Consumer Cause v. Weider Nutrition Internat. 

(2001) 92 Cal.App.4th 363, 370, for its statement that “[former section] 

12201, subdivision (f) [now Cal. Code Regs., tit. 27, § 25102, subd. (i)] defines 

exposure in terms of a chemical . . . coming into contact with a person.” 

Consumer Cause did not consider whether selling or otherwise providing a 

product containing a listed chemical to a consumer constitutes exposing the 

consumer to the chemical. The issue in that case was whether the 

defendants exposed consumers to cancer-causing chemicals through products 

that did not contain any listed chemical but, when ingested, caused a 

chemical reaction in the body that increased natural levels of testosterone, 
61

which can cause cancer. Holding the defendants’ products did not expose 

consumers to cancer-causing chemicals within the meaning of Proposition 65, 

the Consumer Cause court explained that “ ‘[t]he Act prohibits all means of 

directly bringing individuals into contact with chemicals known to the state 

to cause cancer . . .’ ” and the products at issue did not do so, since the 

increase in testosterone occurred only as a result of a reaction inside the 

body. (Consumer Cause, at p. 369.) The court further emphasized that ballot 

materials for Proposition 65 “focus[ed] on exposure to carcinogenic chemicals” 

and did not suggest Proposition 65 “was intended to apply when a person is 

exposed to a noncarcinogenic chemical which then causes a substance 

naturally occurring in the body to become carcinogenic.” (Consumer Cause,

at p. 370.) 

Amazon argues that the need for evidence of “actual exposure” was 

particularly important in the present case because the total number of sales 

at issue was relatively small and there was a public health campaign to 

discourage use of skin-lightening creams, including a buy-back program that 

recovered some products before they were used. Aside from factual questions 

such as whether consumers who purchased the products at issue were aware 

of the public health notices or participated in the buy-back program, this 

argument begs the relevant question. The argument is premised on the 

assumption that Amazon cannot be said to have exposed a consumer to 

mercury in a skin-lightening cream unless and until the consumer has 

actually applied the cream to his or her skin. As we have explained, however, 

we understand “expose” as used in Health and Safety Code section 25249.6 as 

referring to potential as well as realized exposure from a product being used 

in the intended manner—“[l]aying an individual open to a chemical hazard” 
62

by an “act which propels the product toward the individual.” (1988 FSOR, 

supra, p. 19.) 

Amazon certainly meets this definition. As described by the court in 

Bolger, supra, 53 Cal.App.5th at page 438, “Amazon placed itself between 

[the third-party seller and customer] in the chain of distribution of the 

product at issue here” by attracting customers to the Amazon Web site, 

providing product listings for the skin-lightening creams, receiving payment 

for the products, requiring communication between third-party sellers and 

customers to go through the Amazon Web site, demanding indemnification 

and fees for each purchase, and, for products using the FBA program,

accepting possession of the product, storing it in an Amazon warehouse, and 

shipping it to the customer. “Whatever term we use to describe Amazon’s 

role, be it ‘retailer,’ ‘distributor,’ or merely ‘facilitator,’ it was pivotal in 

bringing the product here to the consumer.” (Ibid.)

Finally, Amazon argues we should infer Lee attempted but was unable 

to discover any evidence of “actual exposure” from the fact that Lee obtained 

an order from the trial court compelling Amazon to provide contact 

information for purchasers of the products at issue, but did not present any 

evidence of actual use of the products. Lee’s motion to compel argued the 

contact information was “primarily relevant because it relates to Amazon’s 

defense that it should not be required to send warnings to purchasers ‘who 

have since used all the products,”35 as Amazon had not offered any evidence 

35 When Lee sought a preliminary injunction, one of Amazon’s 

arguments in opposition was that “[i]f the injunction is entered, Amazon will 

be required to email purchasers of third-party products who have since used 

all the Products—informing them that products they used might have 

contained mercury . . . ,” which would not prevent further violations of 

Proposition 65, but “simply upset Amazon’s customers, over products Amazon 

didn’t even sell.” The trial court denied the request for this emailed notice. 
63

that customers were no longer using the creams they purchased. Lee also 

argued the customer contact information would lead to discovery of percipient 

witnesses and material relevant to Amazon’s liability, with respect to both 

exposure and Amazon’s operations and knowledge. In granting the motion to 

compel, the trial court found Lee had “sufficiently shown that the contact 

information of consumers who purchased the skin creams may well lead to 

relevant and/or admissible information, including as to: (1) the nature of the 

transactions and Amazon’s role in them; (2) the extent to which a Proposition 

65 warning was available or known to the consumer; (3) the extent to which 

the consumers (or their family members) were exposed to the product; (4) the 

extent to which exposures continue; and (5) whether there was any 

communication with Amazon about the mercury or other content.” Amazon 

provided access to the customer contact information. 

Neither the record nor Lee’s briefs explain why he did not present 

evidence of individual consumers’ use of the skin-lightening products. But we 

see no reason to infer customers who purchased skin-lightening creams 

through the Amazon Web site did not use them. “Things happen according to 

the ordinary course of nature and the ordinary habits of life.” (Civ. Code, 

§ 3546.) It is at least as likely Lee was unable to locate purchasers of the 

products willing to participate in this litigation, or decided not to pursue this 

source of potential evidence. Regardless, in light of our interpretation of 

Health and Safety Code section 25249.6, evidence of actual use was not 

necessary to establish the “expose” element of Lee’s claims.36

36 We are not persuaded by Lee’s argument that the trial court 

precluded him from presenting the evidence of use it then found he failed to 

present. Lee points out that when his attorney asked Copan what evidence 

the CDPH found that skin-whitening cream was responsible for mercury 

contamination in homes, the trial court sustained Amazon’s objection that 
64

IV.

Lee contends the trial court erred in finding Amazon immune from 

liability for violating Proposition 65 under section 230 of the federal CDA. 

(§ 230(c)(1).) In relevant part, that section states, “No provider or user of an 

interactive computer service shall be treated as the publisher or speaker of 

any information provided by another information content provider.” (Ibid.) 

The statute expressly preempts state laws that are inconsistent with its 

terms: “Nothing in this section shall be construed to prevent any State from 

enforcing any State law that is consistent with this section. No cause of 

action may be brought and no liability may be imposed under any State or 

local law that is inconsistent with this section.” (§ 230(e)(3).)

“ ‘Taken together, these provisions bar state-law plaintiffs from holding 

interactive computer service providers legally responsible for information 

created and developed by third parties. [Citation.] Congress thus 

established a general rule that providers of interactive computer services are 

liable only for speech that is properly attributable to them. [Citation.] Statethese investigations had no connection to products sold through Amazon. 

Lee’s attorney stated that Amazon’s brief had “argued there was no way to 

prove exposure from people purchasing skin-lightening creams” and “[w]hile 

it may seem rather obvious, I feel we now need to prove that people who use 

products that they purchase, and Ms. Copan has personal knowledge of how 

people have used other skin-lightening creams.” The court responded, “I 

don’t think the Judge needs a witness on that. I’m going to have to make a 

decision as to the application of the regs and the statue, as to whether ‘ingest’ 

means to physically ingest or whether it’s reasonably foreseeable a product 

will be used in the manner anticipated. . . . I don’t need Ms. Copan for that. 

[¶] As my father would say, that’s common sense. The issue is what the law 

is.” What the court precluded was testimony about how skin-lightening 

creams are used in general; what the court subsequently found lacking in 

Lee’s case was evidence that the specific products at issue in this case were in 

fact used by a consumer after being purchased through Amazon’s Web site.
65

law plaintiffs may hold liable the person who creates or develops unlawful 

content, but not the interactive computer service provider who merely 

enables that content to be posted online.’ (Nemet Chevrolet, Ltd. v. 

Consumeraffairs.com, Inc. (4th Cir. 2009) 591 F.3d 250, 254.)” (Bolger, supra, 

53 Cal.App.5th at p. 463.)

“ “[S]ection 230(c)(1) precludes liability that treats a website as the 

publisher or speaker of information users provide on the website. In general, 

this section protects websites from liability for material posted on the website 

by someone else.” (Doe v. Internet Brands, Inc. (9th Cir. 2016) 824 F.3d 846, 

850 (Internet Brands, Inc.).) “Immunity under section 230 extends to ‘ “(1) a 

provider or user of an interactive computer service (2) whom a plaintiff seeks 

to treat, under a state law cause of action, as a publisher or speaker (3) of 

information provided by another information content provider.” ’ 

(HomeAway.com, Inc. v. City of Santa Monica (9th Cir. 2019) 918 F.3d 676, 

681 (HomeAway.com).)” (Bolger, supra, 53 Cal.App.5th at p. 463.) 

“[P]ublication involves reviewing, editing, and deciding whether to publish or 

to withdraw from publication third-party content . . . . [A] publisher reviews 

material submitted for publication, perhaps edits it for style or technical 

fluency, and then decides whether to publish it.” (Barnes v. Yahoo!, Inc. (9th 

Cir. 2009) 570 F.3d 1096, 1102–1103 (Barnes).) 

The trial court concluded all the elements of CDA immunity were 

satisfied in the present case, finding Amazon is an interactive computer 

service provider, Lee’s claim is “predicated on information provided by 

another information content provider (i.e., the third-party sellers that 

provided the product descriptions without a Proposition 65 warning),”37 and 

37 The trial court quoted Oberdorf v. Amazon.com Inc. (M.D.Pa. 2017) 

295 F.Supp.3d 496, 501, a products liability case in which the district court 
66

Lee “seeks to treat Amazon as the publisher or speaker of that information.” 

The trial court viewed Lee’s claims as seeking to impose liability on Amazon 

for “allowing third parties to list products for sale on its website without 

altering the disclosures and other content supplied by those third parties as 

to their own manufactured products.” 

Lee does not suggest Amazon is not an interactive computer service 

provider within the meaning of section 230, and does not dispute that the 

product descriptions for products sold on the Web site by third parties are 

provided by those parties.38 He argues, however, that his claims are not 

precluded by section 230 because they do not seek to treat Amazon as the 

publisher or speaker of information provided by the third-party sellers, but 

stated, “ ‘Like an auctioneer, Amazon is merely a third-party vendor’s “means 

of marketing,” since third-party vendors—not Amazon—“cho[o]se the 

products and expose[]” them for sale by means of: the Marketplace.’ ” The 

same day the trial court entered judgment, Oberdorf was affirmed in part 

and vacated in part (Oberdorf v. Amazon.com Inc. (3d Cir. 2019) 930 F.3d 

136, 153–154) in a decision which was then vacated when a petition for 

rehearing en banc was granted (Oberdorf v. Amazon.com Inc. (3d Cir. 2019) 

936 F.3d 182). The Third Circuit has since certified for review by the 

Pennsylvania Supreme Court the question whether, under Pennsylvania law, 

an “e-commerce business, like Amazon” is strictly liable for a defective 

product in the circumstances of that case. (Oberdorf v. Amazon.com, Inc. (3d 

Cir. 2020) 818 Fed. Appx. 138, 143.)

38 “Section 230 defines an ‘ “interactive computer service” ’ as ‘any 

information service, system, or access software provider that provides or 

enables computer access by multiple users to a computer server, including 

specifically a service or system that provides access to the Internet and such 

systems operated or services offered by libraries or educational institutions.’ 

(§ 230(f)(2).) The term ‘ “information content provider,” ’ meanwhile, ‘means 

any person or entity that is responsible, in whole or in part, for the creation 

or development of information provided through the Internet or any other 

interactive computer service.’ (§ 230(f)(3).)” (Hassell, supra, 5 Cal.5th at 

p. 535.)
67

rather to hold Amazon accountable for violation of its own independent 

obligations under Proposition 65.

“Congress enacted section 230 ‘for two basic policy reasons: to promote 

the free exchange of information and ideas over the Internet and to 

encourage voluntary monitoring for offensive or obscene material.’ ” (Hassell 

v. Bird (2018) 5 Cal.5th 522, 534 (Hassell), quoting Carafano v. 

Metrosplash.com, Inc. (9th Cir. 2003) 339 F.3d 1119, 1122.) The Ninth 

Circuit has explained: “As the heading to section 230(c) indicates, the 

purpose of that section is to provide ‘[p]rotection for “Good Samaritan”

blocking and screening of offensive material.’ That means a website should 

be able to act as a ‘Good Samaritan’ to self-regulate offensive third party 

content without fear of liability.” (Internet Brands, Inc., supra, 824 F.3d at 

pp. 851–852.) 

Section 230 was enacted in part in reaction to an unpublished state 

court decision39 holding that “an internet service provider became a 

‘publisher’ of offensive content on its message boards because it deleted some 

offensive posts but not others.” (Internet Brands, Inc., supra, 824 F.3d at 

p. 852.) Under the state court’s reasoning “a website had to choose between 

voluntarily removing some offensive third party content, which would expose 

the site to liability for the content it did not remove, or filtering nothing, 

which would prevent liability for all third party content. [Citation.] ‘In 

passing section 230, Congress sought to spare interactive computer services 

this grim choice by allowing them to perform some editing on user-generated 

content without thereby becoming liable for all defamatory or otherwise 

unlawful messages that they didn’t edit or delete.’ ” (Ibid., quoting Fair 

39 Stratton Oakmont, Inc. v. Prodigy Servs. Co., 1995 WL 323710 (N.Y. 

Sup. Ct. May 24, 1995)
68

Hous. Council v. Roommates.Com, LLC (2008) 521 F.3d 1157, 1163

(Roommates.Com).) “Simply put, the immunity provision was “ ‘enacted to 

protect websites against the evil of liability for failure to remove offensive 

content.’ ” (Internet Brands, Inc., at p. 852.)

Congress intended section 230 “ ‘ “to promote the continued 

development of the Internet and other interactive computer services . . . [and] 

to preserve the vibrant and competitive free market that presently exists for 

the Internet and other interactive computer services, unfettered by Federal 

or State regulation.” [Citations.] To that end, CDA immunity is to be 

construed broadly, “to protect websites not merely from ultimate liability, but 

from having to fight costly and protracted legal battles. ” ’ (Cross v. Facebook, 

Inc. (2017) 14 Cal.App.5th 190, 206, 222.)” (Bolger, supra, 53 Cal.App.5th at 

p. 463.)

Quoting Gentry v. eBay, Inc. (2002) 99 Cal.App.4th 816, 828 (Gentry), 

the trial court stated that section 230(c)(1) “preempts state law and ‘by its 

“plain language,” created a federal immunity to any cause of action that 

would make interactive service providers liable for any information 

originating with a third-party user of this service.’ ” In the trial court’s view, 

“all of the content at issue was provided by third-party sellers, not Amazon,” 

the third-party sellers did not provide Proposition 65 warnings and “[t]hus, if 

there is liability here, it is predicated entirely on the deficiencies in thirdparty content on Amazon’s online marketplace.” The trial court described 

Lee’s claim as seeking to “treat Amazon as the publisher or speaker” of 

“information provided by another information content provider (i.e., the 

third-party sellers that provided the product descriptions without a 

Proposition 65 warning)” and held it would be inconsistent with section 

230(c)(1) to impose liability on Amazon for “failing to include a warning on 
69

products sold on its website by third parties, based on product content 

developed by those third parties without any encouragement, assistance or 

direction from Amazon, and without evidence that Amazon was aware of the 

chemical content of those products before allowing the third parties to list 

them on its website.” The court viewed Lee’s claims as based on Amazon 

“allowing third parties to list products for sale on its website without altering 

the disclosures and other content supplied by those third parties as to their 

own manufactured products.” 

Amazon views Gentry as “determinative precedent.” In that case, 

purchasers of what turned out to be forged autographed sports memorabilia 

alleged eBay violated Civil Code section 1739.7, which requires dealers of 

collectibles to furnish a certificate of authenticity to purchasers of 

autographed sports collectibles. (Gentry, supra, 99 Cal.App.4th at p. 820.) 

Although the plaintiffs argued they were attempting to enforce eBay’s 

independent duty to furnish a warranty under Civil Code section 1739.7, the 

Gentry court held section 230 barred the claims because imposing liability on 

eBay would hold it responsible, as publisher, for content originating with 

other parties, as it was the individual sellers who falsely identified the 

product as authentically autographed in order to sell it on eBay. (Gentry, at 

pp. 831–832.) Other causes of action were similarly barred because they 

sought to hold eBay responsible for having notice of illegal conduct by third 

parties and failing to take action such as withdrawing or altering the content 

provided by those parties that would amount to “exercise of a publisher’s 

traditional editorial functions.” (Id. at p. 835.)

We do not see Gentry as dispositive of the issues in the present case. 

Lee does not suggest Amazon had any obligation to alter the content of the 

product descriptions provided by the third-party sellers or even to remove the 
70

listings altogether. Instead, Lee maintains Amazon should have added its 

own Proposition 65 warning, pursuant to its independent obligation under 

Proposition 65, based on its conduct in providing a mercury-containing 

product to consumers. In Gentry, the plaintiffs’ argument that they were 

seeking to enforce eBay’s independent duty to provide the warranty of 

authenticity was unpersuasive because the statutory duty applied only to 

dealers in sports collectibles, and the plaintiffs’ “specific allegations reveal 

eBay is not in the business of selling or offering to sell the collectibles at 

issue; rather, it is the individual defendants who sold the items to plaintiffs, 

using eBay as a venue.” (Gentry, supra, 99 Cal.App.4th at p. 827.) Here, 

Proposition 65 imposes a duty to warn on every business that “exposes” an 

individual to a listed chemical. As we have said, Amazon did so by its 

“pivotal” role in “bringing the product here to the consumer.” (Bolger, supra, 

53 Cal.App.5th at p. 438; 1988 FSOR, p. 19 [“propel[ling] the product toward 

the individual”].) Lee’s claims are based on Amazon’s conduct in exposing 

consumers to mercury-containing products without providing Proposition 65 

warnings, not its failure to monitor, modify or remove third parties’ listings 

for the products, and thus do not require treating Amazon as speaker or 

publisher of third-party content.40

40 Like Gentry, other cases Amazon cites involved claims that 

necessarily based the defendants’ alleged liability on actions traditionally 

within a publisher’s role. In Cross v. Facebook, supra, 14 Cal.App.5th at 

pages 194 and 207, we held CDA immunity barred claims seeking to impose 

liability for Facebook’s failure to remove posts by users that allegedly incited 

violence and generated death threats against the plaintiffs. Chicago 

Lawyers’ Committee for Civil Rights Under Law, Inc. v. Craigslist, Inc. (7th 

Cir. 2008) 519 F.3d 666, 668, 672, held section 230 barred claims that 

Craigslist.com violated laws against housing discrimination by hosting user 

posts advertising, for example, “no minorities” or “no children.” Eberhart v. 

Amazon.com, Inc. (S.D.N.Y. 2018) 325 F.Supp.3d 393, 400, footnote. 5, which 
71

Contrary to Amazon’s characterization, enforcing its obligations under 

Proposition 65 does not require it to “monitor, review, and revise” product 

listings. As both Lee and the Attorney General point out, the “knowingly and 

intentionally” requirement in Health and Safety Code section 25249.6 means 

Amazon is required to provide a warning where it has knowledge a product 

contains a listed chemical—for example, from public health alerts or direct 

notice. We recognize that any responsibility to provide warnings Amazon 

might have under section 25249.6 would not result in liability if the thirdparty seller of a skin-lightening product itself provided a Proposition 65 

warning,41 and that Amazon would have to review the product’s packaging 

and/or listing on the Web site to determine whether a warning was provided 

by the third-party seller. These facts do not mean Lee’s claims necessarily 

treats Amazon as a speaker or publisher of information provided by the thirdparty sellers. If Amazon has actual or constructive knowledge that a product 

contains mercury, it might choose to review the product listing to determine 

held Amazon could not be held liable for injuries due to a defective product 

sold by a third-party seller, noted in passing that section 230 would bar any 

claim against Amazon “for the content it permitted [the seller] to post” on the 

Web site. La Park La Brea A LLC v. Airbnb, Inc. (C.D.Cal. 2017) 285 

F.Supp.3d 1097, 1106, held section 230 barred a suit by the owner of 

apartments listed for rent on Airbnb.com in violation of the tenants’ lease 

prohibition against subletting. Doe v. Backpage.Com, LLC (1st Cir. 2016) 

817 F.3d 12, 22, applied section 230 immunity to claims that the Web site

facilitated sex trafficking by enabling sex traffickers to advertise their 

victims for “escort” services. Daniel v. Armslist, LLC (Wis. 2019) 926 N.W.2d 

710, held section 230 barred claims against a Web site that hosts ads by 

prospective sellers and purchasers of firearms for facilitating the illegal 

purchase of the weapon used in a mass shooting.

41 Regulations section 25600.2, adopted in 2016, makes clear that the 

essential requirement is provision of a warning to the consumer, and 

expressly permits the parties in the chain of distribution to determine which 

one will be responsible for providing it.
72

whether the third-party seller had provided a Proposition 65 warning before

providing the warning itself or removing the listing. But nothing inherently 

requires Amazon to do so. It could choose, instead, to act on its knowledge by 

providing the warning regardless, pursuant to its own obligations under 

Proposition 65. 

HomeAway.com provides an example, albeit in different factual 

circumstances. HomeAway and another company whose Web site similarly 

allows individuals seeking rental accommodations to connect with hosts 

offering such rentals, challenged a city ordinance prohibiting short-term 

home rentals except for licensed home-shares in which residents remain on 

site with guests. (HomeAway.com, supra, 918 F.3d at p. 679.) The plaintiffs 

argued the ordinance was preempted by section 230 because it required them 

to monitor and remove third-party content—listings not in compliance with 

the ordinance. (Id. at p. 682.) The court explained that while the plaintiffs 

might choose to monitor or remove listings, the ordinance did not require 

them to do so, only to cross-reference the city’s registry of licensed rentals 

before processing a requested booking. (Id. at pp. 682–683.) 

As our Supreme Court has observed, “not all legal duties owed by 

Internet intermediaries necessarily treat them as the publishers of thirdparty content, even when these obligations are in some way associated with 

their publication of this material. (See, e.g., Barnes, supra, 570 F.3d at 

p. 1107 [regarding § 230 immunity as inapplicable to a claim of promissory 

estoppel alleging that an Internet intermediary promised to remove offensive 

content].)” (Hassell, supra, 5 Cal.5th at pp. 542–543.) Similarly, the Ninth 

Circuit has said “[i]t is not enough that third-party content is involved” and

has “rejected use of a ‘but-for’ test that would provide immunity under the 

CDA solely because a cause of action would not otherwise have accrued but 
73

for the third-party content. [Citation.] We look instead to what the duty at 

issue actually requires[.]” (HomeAway.com, supra, 918 F.3d at p. 682.) “ ‘In 

evaluating whether a claim treats a provider as a publisher or speaker of 

user-generated content, “what matters is not the name of the cause of action”; 

instead, “what matters is whether the cause of action inherently requires the 

court to treat the defendant as the ‘publisher or speaker’ of content provided 

by another.” [Citation.] Put slightly differently, “courts must ask whether 

the duty that the plaintiff alleges the defendant violated derives from the 

defendant’s status or conduct as a ‘publisher or speaker.’ If it does, section 

230(c)(1) precludes liability.” ’ (Cross [v. Facebook], supra, 14 Cal.App.5th at 

p. 207.)” (Bolger, supra, 53 Cal.App.5th at p. 464.)

Bolger, supra, 53 Cal.App.5th at page 439, a products liability case 

involving a defective computer battery purchased from a third-party seller on 

Amazon’s Web site, held section 230 did not shield Amazon from liability 

because the plaintiff’s strict liability claims “depend on Amazon’s own 

activities, not its status as a speaker or publisher of content provided by [the 

third-party seller] for its product listing.” The court first concluded that 

Amazon’s extensive role in third-party sales, especially where the seller 

utilizes the FBA program (as in Bolger and for at least one of the products 

here), supported application of strict liability, describing that role in terms 

consistent with the evidence in this case. (Bolger, at pp. 452–453; Loomis v. 

Amazon.com LLC (2021) 63 Cal.App.5th 466 [agreeing with Bolger in case 

where seller did not use FBA].)42 After discussing two cases from other 

42 The Bolger court noted that “Amazon created the environment (its 

website) that allowed [the third-party seller] to offer the replacement battery 

for sale”; “attracted customers through its own activities”; “set the terms of 

[the seller’s] involvement”; “demanded fees in exchange for [the seller’s]

participation”; “required [the seller] to indemnify it”; “accepted possession of 
74

jurisdictions that declined to apply section 230 immunity to strict liability 

claims, Bolger stated: “We agree with Erie [Ins. Co. v. Amazon.com Inc. (4th 

Cir. 2019) 925 F.3d 135] and State Farm [Fire & Cas. Co. v. Amazon.com Inc.

(W.D.Wis. 2019) 390 F.Supp.3d 964] on this issue. Bolger’s strict products 

liability claims target Amazon’s role in ‘the vertical distribution of consumer 

goods’ (Bay Summit [Community Assn. v. Shell Oil Co. (1996)] 51 Cal.App.4th 

[762,] 773) as an ‘integral part of the overall producing and marketing 

enterprise’ for the [third-party seller’s] replacement laptop battery 

(Vandermark [v. Ford Motor Co. (1964)] 61 Cal.2d [256,] 262). It is based on 

Amazon’s own conduct, as described above, not the content of [the third-party 

seller’s] product listing. Bolger’s claims do not require a court to treat 

Amazon as the speaker or publisher of content provided by [the third-party 

seller]. The content of the product listing is not determinative, and it need 

not be attributed to Amazon to support strict liability. Instead, Amazon’s 

own involvement in the distribution of an allegedly defective product 

[the seller’s] products, registered them in its inventory system, and stored 

them in an Amazon warehouse awaiting sale”; “created the format for [the 

seller’s] offer for sale”; and “allowed [the seller] to use a fictitious name in its 

product listing.” (Bolger, supra, 53 Cal.App.5th at p. 452.) Additionally, the 

product listing “does not conspicuously inform the consumer of the identity of 

the third party seller or the nature of Amazon’s relationship to the sale”; the 

customer purchases the product by adding it to her Amazon cart and pays 

Amazon; under the FBA program, Amazon personnel retrieve the product 

from an Amazon warehouse and ship it to the customer in Amazon branded 

packaging (potentially together with items purchased from other sellers or 

Amazon itself); the seller is not involved in the sales transaction and “does 

not receive payment until Amazon chooses to remit the proceeds”; the 

customer sends returns to Amazon; and third-party sellers “are prohibited 

from communicating with Amazon customers except through the Amazon 

website, where such interactions are anonymized.” (Id. at pp. 452–453.)
75

supports strict liability for the reasons we have already discussed.” (Bolger, 

at p. 464.)

Other cases similarly distinguish claims that treat an interactive 

computer service provider as a publisher from claims that do not, despite 

being associated with third-party content. In Barnes, supra, 570 F.3d 1096, 

after a period of failing to respond to the plaintiff’s requests to remove 

indecent material her former boyfriend posted without her consent on 

Yahoo.com, the company expressly promised to remove the material, then did 

not do so. (Id. at pp. 1098–1099.) The Ninth Circuit concluded the plaintiff’s 

cause of action for “negligent undertaking” was barred by section 230 because 

it sought to hold Yahoo liable for failing to remove the offending material, 

which was publishing activity.

The plaintiff’s cause of action for promissory estoppel, however, was not 

barred. (Barnes, supra, 570 F.3d at p. 1109.) Although the promise 

underlying this claim involved the same conduct—removing the material 

from the Web site—the duty allegedly violated “springs from a contract—an 

enforceable promise—not from any non-contractual conduct or capacity of the 

defendant.” “Contract liability here would come not from Yahoo’s publishing 

conduct, but from Yahoo’s manifest intention to be legally obligated to do 

something, which happens to be removal of material from publication.” (Id. 

at p. 1107.) The “outwardly manifested intention to create an expectation on 

the part of another . . . generates a legal duty distinct from the conduct at 

hand, be it the conduct of a publisher, of a doctor, or of an overzealous uncle.” 

(Id. at p. 1108.)

Internet Brands, Inc., supra, 824 F.3d 846 provides another illustration 

of the same point. There, two individuals used the defendant’s Web site, a 

networking Web site for the modeling industry, to lure the plaintiff to sham 
76

auditions where she was drugged and raped. (Id. at p. 848.) The plaintiff 

alleged that the Web site owner had independent knowledge of the ongoing 

scheme but failed to warn her or other Web site users, in violation of a duty 

to warn imposed by California law, and the district court dismissed the action 

as barred by section 230. (Internet Brands, Inc., at pp. 848–850.) Reversing, 

the Ninth Circuit explained that the plaintiff did not seek to hold the Web 

site owner liable as publisher or speaker of a third party’s posted content, for 

failing to remove such content or for any conduct related to monitoring or 

failing to monitor posts on the Web site. (Id. at p. 851.) Instead, the plaintiff 

argued the defendant was liable for failure to warn her about information 

obtained from an outside source about the scheme being perpetrated on its 

Web site, which could be accomplished without altering or removing the 

third-party content, for example, by posting a warning on the Web site or 

emailing users. (Ibid.) Accordingly, the negligent failure to warn claim did

not seek to hold the Web site owner liable as the “ ‘publisher or speaker of 

any information provided by another information content provider’ ” and 

section 230 did not bar the claim. (Internet Brands, Inc., at p. 851.)

Here, Lee claims Amazon violated Proposition 65 exposing consumers 

to mercury without warnings through its own conduct. The claims do not 

attempt to hold Amazon responsible for third-party sellers’ content (except in 

the sense that Amazon would have been able to disclaim responsibility for 

providing warnings if the sellers had provided them). As we have discussed, 

the claims do not require Amazon to modify or remove third-party content

but rather to provide a warning where Amazon’s own conduct makes it 

subject to Health and Safety Code section 25249.6.

The Ninth Circuit cases make another point that is of critical 

importance here. HomeAway.com emphasized that “[l]ike their brick-and-
77

mortar counterparts, internet companies must also comply with any number 

of local regulations concerning, for example, employment, tax, or zoning” and 

“allowing internet companies to claim CDA immunity under these 

circumstances would risk exempting them from most local regulations 

and . . . ‘create a lawless no-man’s-land on the Internet.’ ” (HomeAway.com, 

supra, 918 F.3d at p. 683, quoting Roommates.com, supra, 521 F.3d at 

p. 1164.) The court explained, “We have consistently eschewed an expansive 

reading of [section 230] that would render unlawful conduct ‘magically . . .

lawful when [conducted] online,’ and therefore ‘giv[ing] online businesses an 

unfair advantage over their real-world counterparts.’ ” (HomeAway, at 

p. 683, quoting Roommates.com, at p. 1164.) In this respect, “ ‘we must be 

careful not to exceed the scope of the immunity provided by Congress.’ ” 

(Internet Brands, Inc., supra, 824 F.3d at p. 853, quoting Roommate.com, at 

p. 1164, fn. 15.) 

If a skin-lightening cream is sold in a brick-and-mortar drug store that 

was aware the product contained mercury, there is no question that retail 

seller would have some obligation to provide Proposition 65 warnings—

depending, of course, on whether entities further up the distribution chain 

had provided warnings for the products and, if not, could be held to account. 

Nothing in the text or purposes of the CDA suggests it should be interpreted 

to insulate Amazon from responsibilities under Proposition 65 that would 

apply to a brick-and-mortar purveyor of the same product. 

Not only would such an interpretation give Amazon a competitive 

advantage unintended by Congress in enacting the CDA, but it would be 

inimical to the purposes of Proposition 65. Amazon makes it possible for 

sellers who might not be able to place their products in traditional retail 

stores to reach a vast audience of potential customers. (E.g., Bolger, supra, 
78

53 Cal.App.5th at p. 453 [“The Amazon website . . . enables manufacturers 

and sellers who have little presence in the United States to sell products to 

customers here”].) The evidence in this case indicates that mercurycontaining skin-lightening products are overwhelmingly likely to have been 

manufactured outside the United States—unsurprisingly, as FDA 

regulations prohibit use of mercury as a skin-lightening agent in cosmetics. 

(21 C.F.R. § 700.13.) This makes it all the more likely Amazon may be the 

only business that can readily be compelled to provide a Proposition 65 

warning for these products. (See 2016 FSOR, supra, p. 55 [discussing

impracticality of enforcing warning requirement against foreign entity 

without agent for service of process in United States]; Bolger, supra, 

53 Cal.App.5th at p. 453 [noting as first factor supporting application of strict 

liability doctrine to Amazon that it “may be the only member of the 

distribution chain reasonably available to an injured plaintiff who purchases 

a product on its website”].) Amazon is thus making available to consumers,

and profiting from sales of, products that clearly require Proposition 65 

warnings, yet are likely to have been manufactured and distributed by 

entities beyond the reach of reasonable enforcement efforts. Insulating 

Amazon from liability for its own Proposition 65 obligations in these 

circumstances would be anomalous. 

Proposition 65, as we have said, “ ‘is a remedial law, designed to protect 

the public’ ” which must be construed “ ‘broadly to accomplish that protective 

purpose.’ ” (Center for Self-Improvement & Community Development v. 

Lennar Corp., supra, 173 Cal.App.4th at pp. 1550–1551, quoting People ex rel. 

Lungren v. Superior Court, supra, 14 Cal.4th at p. 314.) Moreover, states’ 

“police powers to protect the health and safety of their citizens . . . are 

‘primarily, and historically, . . . matter[s] of local concern.’ ” (Medtronic, Inc. 
79

v. Lohr (1996) 518 U.S. 470, 485.) The United States Supreme Court has 

explained that “[w]hen addressing questions of express or implied preemption, we begin our analysis ‘with the assumption that the historic police 

powers of the States [are] not to be superseded by the Federal Act unless that 

was the clear and manifest purpose of Congress.’ [Citation].” (Altria Group, 

Inc. v. Good (2008) 555 U.S. 70, 77.) The “strong presumption against 

displacement of state law . . . applies not only to the existence, but also to the 

extent, of federal preemption. [Citation.] Because of it, ‘courts should 

narrowly interpret the scope of Congress’s “intended invalidation of state 

law” whenever possible.’ [Citation].” (Brown v. Mortensen (2011) 51 Cal.4th 

1052, 1064.) 

As the Ninth Circuit has explained, Congress intended “to preserve the 

free-flowing nature of Internet speech and commerce without unduly 

prejudicing the enforcement of other important state and federal laws. When 

Congress passed section 230 it didn’t intend to prevent the enforcement of all 

laws online; rather, it sought to encourage interactive computer services that 

provide users neutral tools to post content online to police that content 

without fear that through their ‘good samaritan . . . screening of offensive 

material,’ [citation], they would become liable for every single message posted 

by third parties on their website.” (Roommates.com, supra, 521 F.3d at 

p. 1175, quoting § 230(c).)

The text of section 230(e)(3) is clear that state laws inconsistent with 

section 230 are preempted while those consistent with section 230 are not 

preempted. Proposition 65’s warning requirement is an exercise of state 

authority to protect the public that imposes obligations on any individual who 

exposes another to a listed chemical. Proposition 65 is not inconsistent with 

the CDA because imposing liability on Amazon for failing to comply with its 
80

own, independent obligations under Proposition 65, does not require treating 

Amazon as the publisher or speaker of third-party sellers’ content. 

Accordingly, if Lee can establish all the elements of a violation of Proposition 

65, section 230 does not immunize Amazon from liability.

DISPOSITION

The judgment is reversed and the matter is remanded for further 

proceedings in accordance with the views expressed in this opinion. 

On remand, if Lee is able to establish all the elements of his claims as 

to the products purchased from Amazon and tested for mercury content, the 

trial court shall determine whether the products with different ASINs

identified in Lee’s pretrial brief as among the 11 products at issue were in 

fact the same products as the ones for which samples were tested, and shall 

determine penalties in accordance with Health and Safety Code section 

25249.7 for any violations of Proposition 65 established.
81

_________________________

Kline, J.*

We concur:

_________________________

Richman, Acting P.J.

_________________________

Stewart, J.

Lee v. Amazon (A158275)

*Assigned by the Chief Justice pursuant to article VI, section 6 of the 

California Constitution.
82

Trial Court: Alameda County Superior Court

Trial Judge: Hon. Robert McGuiness

Attorney for Plaintiff and Appellant Law Office of Jonathan Weissglass

Larry Lee: Jonathan Weissglass

Greenfire Law

Rachel S. Doughty

Jessica L. Blome

Attorneys for Amicus Curiae on behalf Rob Bonta

of Plaintiff and Appellant: Attorney General of California

Dennis A. Ragen

Roxanne Carter

Deputy Attorneys General

Attorneys for Amicus Curiae Danielle R. Fugere

As you Sow on behalf of Plaintiff Chelsea J. Linsley

Appellant:

Attorneys for Amicus Curiae Altshuler Berzon

Center For Food Safety on behalf Barbara J. Chisholm

of Plaintiff and Appellant: P. Casey Pitts

Attorneys for Amici Curiae Black Environmental Law Clinic

Women for Wellness and the Mercury Mills Legal Clinic at Stanford Law School

Policy Project/Tides Center on behalf Deborah A. Sivas

of Plaintiff and Appellant: Molly Loughney Melius

Attorneys for Defendant Doll Amir & Eley

and Respondent Amazon.com, Inc.: Gregory L. Doll

Brett H. Oberst

Jamie O. Kendall

Lloyd Vu

Attorneys for Amicus Curiae Law Office of Fred. J. Hiestand

The Civil Justice Association of Fred J. Hiestand

California on behalf of Defendant

and Respondent: