Proposition 65: Legal and Technical Implications of Listing PFOA as a Carcinogen

April 21, 2021


Authors: Brett Winters, PhD and Graham Ansell, PhD, GSI Environmental Inc.; Patrick Veasy and Sophia Castillo, Downey Brand LLP

On March 19, 2021, California’s Office of Environmental Health Hazard Assessment (OEHHA) released a Notice of Intent (NOI) to list perfluorooctanoic acid (PFOA) as a carcinogen under Proposition 65 via the Authoritative Bodies mechanism.[i] PFOA belongs to a broad class of chemicals known as per- and polyfluoroalkyl substances (PFAS), which are fluorinated man-made chemicals.

Proposition 65, also known as the Safe Drinking Water and Toxic Enforcement Act of 1986—or “Prop 65”—prohibits businesses from releasing chemicals “known to the state to cause cancer or reproductive toxicity” into drinking water sources, and from exposing people to chemicals on the Proposition 65 List without providing “clear and reasonable” warnings.

It is important to note that while PFOA was used in various manufacturing processes dating back to the 1940s, its manufacture and use in the United States has ceased in recent years. However, due to PFOA’s historical use and persistence in the environment, PFOA concerns may still remain for certain consumer products. Additionally, PFOA may still be used in operations outside the United States and, therefore, may be found in some imported products.

While PFOA has been listed under Proposition 65 as a developmental toxicant since 2017, OEHHA’s NOI to list PFOA as a carcinogen is noteworthy because it will modify warning requirements and increase litigation risk in California, especially in light of active Proposition 65 plaintiffs, who will have yet another basis to initiate Proposition 65 claims. In this article, we provide additional insight on the legal and technical implications tied to OEHHA’s PFOA NOI. Businesses interested in submitting public comments to OEHHA regarding the NOI can do so through May 3, 2021.

PFOA Proposed for Listing as a Carcinogen

As described above, last month OEHHA released a NOI to list PFOA as a carcinogen under Proposition 65 via the Authoritative Bodies mechanism. OEHHA’s NOI is one of the final steps in the process for listing PFOA as a carcinogen under Proposition 65.[ii] Previously, PFOA, as well as PFOA precursors (PFAS that may degrade to form PFOA) were placed in the “High Priority” group for consideration for listing as a carcinogen at a 2009 State’s Qualified Expert Cancer Identification Committee meeting.[iii] OEHHA’s NOI only proposes to list PFOA, however, and does not include PFOA precursors.

OEHHA cited the peer-reviewed 2020 National Toxicology Program (NTP) report titled NTP Technical Report on the Toxicology and Carcinogenesis Studies of Perfluorooctanoic Acid (CASRN 335-67-1) Administered in Feed to Sprague Dawley (Hsd: Sprague Dawley® SD®) Rats as the basis for the PFOA NOI.[iv] NTP is one of five institutions considered by OEHHA as an Authoritative Body for the identification of carcinogens under Proposition 65.[v] The 2020 NTP report identified dose-related increased incidences of liver and pancreatic tumors in male rats and an increased incidence of pancreatic tumors in female rats given PFOA in diet over a two-year period. NTP determined these findings were sufficient to conclude there was clear evidence of carcinogenic activity of PFOA in male rats and some evidence of carcinogenic activity of PFOA in female rats.

While NTP’s conclusions are used as the basis for the NOI, California regulations state that the identification of a chemical as a carcinogen by an Authoritative Body alone is not sufficient for listing under Proposition 65.[vi] OEHHA notes that carcinogenic evidence considered by the Authoritative Body must meet the “sufficiency criteria” as defined under California law (27 California Code of Regulations (CCR) § 25306(e)), which considers sufficient evidence of carcinogenicity in animal studies as:

[A]n increased incidence of malignant tumors or combined malignant and benign tumors in multiple species or strains, in multiple experiments (e.g., with different routes of administration or using different dose levels), or, to an unusual degree, in a single experiment with regard to high incidence, site or type of tumor, or age at onset.[vii]

In light of this, OEHHA is currently accepting public comments through May 3, 2021 on whether PFOA meets the Proposition 65 criteria for listing under the Authoritative Bodies mechanism.

Legal Implications of Listing PFOA as a Carcinogen

Proposition 65 is a powerful regulation because it contains a “citizen attorney general” provision, and citizen plaintiffs frequently enforce it. More specifically, Proposition 65 permits citizens to bring claims against alleged violators, initiated by a document called a 60-Day Notice of Intent to Sue (“Notice”), and to recover their attorneys’ fees in so doing. Proposition 65 also authorizes monetary penalties of up to $2,500 per day for each violation. Proposition 65 “bounty hunter plaintiffs” are active and creative, and looking for new alleged violations of the regulation to enforce, which makes OEHHA’s PFOA NOI particularly relevant.

Proposition 65 prohibits businesses from exposing people to chemicals on the Proposition 65 List without providing “clear and reasonable” warnings unless specific exemptions apply. Thus, assuming that OEHHA ultimately lists PFOA on the Proposition 65 List as a carcinogen, businesses will be required to provide a warning for both developmental toxicity and carcinogenicity on products containing PFOA one year after the carcinogenicity listing by OEHHA.

The costs of compliance with Proposition 65 labeling are significant, as are the costs of defending and resolving Proposition 65 citizen lawsuits if an accurate and adequate warning is not placed on products containing a listed chemical. The defense of a Proposition 65 lawsuit requires time-intensive expert opinions that justify a defendant’s decision not to post a Proposition 65 warning. Because of the costs associated with litigating Proposition 65 claims, recipients of Proposition 65 Notices will typically settle the claims instead of litigating the matter. Settlement costs, per year, result in millions of dollars paid by defendants to citizen plaintiff groups and their attorneys, as well as penalties paid to the State of California.

Implications for Warning Requirements

Currently PFOA is listed under Proposition 65 only as a developmental toxicant. The listing of PFOA as a carcinogen would set the stage for warning label requirements on products with very low levels of PFOA. Under Proposition 65, products do not require a warning label if it can be demonstrated that the normal use of the product will result in an average daily intake less than a chemical-specific exemption level, termed a Safe Harbor Level. Safe Harbor Levels established under Proposition 65 include No Significant Risk Levels (NSRLs) for carcinogens and Maximum Allowable Dose Levels (MADLs) for chemicals causing reproductive toxicity. Proposition 65 allows for OEHHA as well as individuals to derive an NSRL and/or MADL by following methods and assumptions identified in Proposition 65 regulations (27 CCR § 25801).

OEHHA has not yet derived a Safe Harbor Level (NSRL or MADL) for PFOA or other PFAS. However, OEHHA recently derived a cancer slope factor (CSF) for PFOA using the liver and pancreatic tumor data in male rats cited as the basis for the proposed Proposition 65 carcinogenicity listing. [viii] This CSF would result in an NSRL in the low nanogram per day (ng/day) range.

PFOA Analytical Methodologies for Consumer Products

There is currently no standardized or USEPA promulgated analytical method for the identification of PFOA in consumer products. Consequently, compliance with warning label requirements for PFOA and verifying or refuting plaintiff claims will remain a considerable challenge if the compound cannot be reliably identified and quantified in a consumer product.

Promulgated analytical techniques for specific PFAS are currently limited to USEPA drinking water methods 537.1 and 533. Additionally, the Department of Defense QSM Version 5.3 serves as a standardized PFAS analytical guideline. Due to matrix interferences or extraction challenges, analytical laboratories typically must modify these standardized methods when analyzing for PFOA in complex media such as consumer products. USEPA is currently working on additional analytical methods for complex media, though it is unclear if these will include consumer products.

While no standardized analytical method for identification of PFOA in consumer products exists, certain analytical approaches have been utilized for PFAS in consumer products as a preliminary screening level tool. These screening methods, such as total organic fluorine (TOF), particle-induced gamma emission (PIGE), and total oxidizable precursors (TOP), have been used as a first pass to determine whether or not fluorine (either total or organic fluorine) or “precursors” are present in a product. However, these methods are insufficient for identifying a particular PFAS, such as PFOA, and do not quantify PFOA levels in a consumer product. Therefore, if such a screening method indicated the presence of fluorine or organic fluorine, further analysis using a modified method would still be required to determine what specific PFAS are present and at what levels. As these preliminary screening methods cannot identify or quantify a specific PFAS, businesses that receive Proposition 65 Notices based on such methods should carefully scrutinize the analytical results.

Implications and What to Watch

OEHHA’s Notice of Intent to list PFOA as a carcinogen is the latest illustration of California’s intention to expand the regulation of PFAS under Proposition 65. On March 26, 2021, OEHHA requested information on the carcinogenic hazard of perfluorooctanesulfonic acid (PFOS), its salts and transformation and degradation precursors.[ix] If PFOA is listed as a carcinogen under Proposition 65, OEHHA may incorporate this into a future evaluation of PFOS carcinogenicity by noting similarities in chemical structure and activity between the two chemicals.

The listing of PFOA as a carcinogen under Proposition 65 would also reduce current inconsistencies in California’s regulatory approach to PFOA across different regulatory programs. For example, the California State Water Resources Control Board’s (SWRCB) PFOA Notification Level was derived by evaluating PFOA as a carcinogen. Alignment of approaches across agencies will be increasingly relevant if OEHHA’s forthcoming PFOA Public Health Goal (PHG) is also based on a carcinogenic endpoint.

While relatively few Proposition 65 Notices have been filed for PFAS, we expect this to change in the coming years as PFAS analytical methods for consumer products are developed and the number of PFAS listed as reproductive toxicants or carcinogens under Proposition 65 increases. Businesses should continue to track the issues identified above and consider submitting written comments on OEHHA’s PFOA NOI.

Authors

Dr. Brett Winters is a toxicologist and member of the Health Sciences group at GSI Environmental, Inc. He specializes in risk assessment, mechanistic toxicology, and exposure assessment. Brett can be reached at .

Dr. Graham Ansell is a principal chemist at GSI Environmental, Inc., a scientific and engineering consulting firm. He specializes in chemistry, fate and transport, and manufacturing operations and releases mechanisms.

Sophia Castillo is a partner in the San Francisco office of Downey Brand. She specializes in Proposition 65 and toxics law, and publishes an overview of Prop. 65 claims and trends each month with her colleague Patrick Veasy. Sophia can be reached at , or via her LinkedIn page.

Patrick Veasy is a senior associate in Downey Brand’s Sacramento office. Patrick routinely works on matters involving water quality, environmental site remediation issues, and toxic tort litigation, including under Proposition 65. Patrick can be reached at , or via his LinkedIn page.


[i] Cal. Env’t Prot. Agency, Office of Env’t Health Hazard Assessment, Notice of Intent to List Chemical by the Authoritative Bodies Mechanism: Perfluorooctanoic Acid (March 19, 2021), https://oehha.ca.gov/media/downloads/crnr/p65noilabpfoacancer2021p.pdf.

[ii] Cal. Env’t Prot. Agency, Office of Env’t Health Hazard Assessment, Listing via the Authoritative Bodies Mechanism 9(June 2019), https://oehha.ca.gov/media/downloads/proposition-65/policy-procedure/ldfig3.pdf.

[iii] Cal. Env’t Prot. Agency, Office of Env’t Health Hazard Assessment, Carcinogen Identification Committee Meeting (May 29, 2009), https://oehha.ca.gov/proposition-65/events/may-29-2009-carcinogen-identification-committee-meeting.

[iv] Nat’l Toxicology Program, Technical Report on the Toxicology and Carcinogenesis Studies of Perfluorooctanoic Acid (CASRN 335-67-1) Administered in Feed to Sprague Dawley (Hsd: Sprague Dawley® SD®) Rats (May 2020), https://ntp.niehs.nih.gov/ntp/htdocs/lt_rpts/tr598_508.pdf.

[v] Cal. Env’t Prot. Agency, Office of Env’t Health Hazard Assessment, How Chemicals Are Added to the Proposition 65 List, https://oehha.ca.gov/proposition-65/how-chemicals-are-added-proposition-65-list.

[vi] Cal. Env’t Prot. Agency, Office of Env’t Health Hazard Assessment, Notice of Intent to List Chemical by the Authoritative Bodies Mechanism: Perfluorooctanoic Acid (March 19, 2021), https://oehha.ca.gov/media/downloads/crnr/p65noilabpfoacancer2021p.pdf.

[vii] 27 CCR § 25306(e)(2).

[viii] Cal. Env’t Prot. Agency, Office of Env’t Health Hazard Assessment, Notification Level Recommendations, Perfluorooctanoic Acid and Perfluorooctane Sulfonate in Drinking Water (August 2019), https://oehha.ca.gov/media/downloads/water/chemicals/nl/final-pfoa-pfosnl082119.pdf.

[ix] Cal. Env’t Prot. Agency, Office of Env’t Health Hazard Assessment, Chemicals Selected for Consideration for Listing by the Developmental and Reproductive Toxicant Identification Committee (PFDA, PFHxS, PFNA, PFUnDA) (March 26, 2021), https://oehha.ca.gov/media/downloads/crnr/dartchemicalsdatacall-innotice2021.pdf.