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Special Focus

Proposition 65 Actions that May Affect Plastics

Author: Devon Wm. Hill
First Published in: Thermoforming Quarterly

Over twenty-five years ago, California voters approved the ballot initiative known as Proposition 65 ("Prop 65"). Formally known as The Safe Drinking Water and Toxic Enforcement Act of 1986 ,[1] this law requires California to publish a list of chemicals "known to the State to cause cancer or reproductive toxicity." For chemicals that are listed under Prop 65, the law prohibits the knowing discharge or release into water or into or onto land where the substance will pass into a source of drinking water, and the knowing exposure of any individual to a significant amount of the substance without first providing a "clear and reasonable warning." It is the warning requirement that is relevant to the plastics supply chain, as it applies to potential consumer product, workplace, and environmental exposures. We focus here on the consumer product angle.

The intent of Proposition 65 was to establish a right-to-know law that would notify Californians regarding their potential exposure to listed chemicals. In practice, Proposition 65 is a chemical deselection initiative that encourages consumer abandonment of products that have a warning. [2] It is the responsibility of the manufacturer of the finished consumer product to determine whether its products can reasonably be expected to result in a significant exposure; fear of product deselection has resulted in downstream businesses often being more sensitive than individual consumers, and suppliers are often asked whether their products contain any chemicals listed under Prop 65. For upstream suppliers that sell intermediates for use in California, an evaluation of these products and the full range of their potential downstream uses is required to determine whether a warning under Proposition 65 would be required.

The statute contains an exemption from the requirement to warn if the potential exposure to a listed carcinogen "poses no significant risk" or to a listed reproductive toxicant will have "no observable effect." Notably, the statute does not define the key phrases "no significant risk" or "no observable effect." However, the implementing regulations establish "safe harbor" levels in the form of "no significant risk levels" (NSRL) for carcinogens and "maximum allowable daily levels" (MADLs) for reproductive toxicants. When the use of a listed chemical will result in exposures below the safe harbor, no warning label is required. The Office of Environmental Health Hazard Assessment (OEHHA) within the California Environmental Protection Agency, which administers Prop 65, has established over 300 official safe harbor levels for listed substances. Even in the absence of a safe harbor level, companies can use risk assessment techniques to develop their own NSRL or MADL and determine whether the potential exposure from the intended use of the product would exceed those amounts, thereby requiring a warning. OEHHA also may issue Safe Use Determinations (SUDs) confirming that no warning is required for a particular application or category based on a showing that exposures from a specific use will not present a significant risk.

Two chemicals have faced significant Prop 65 activity: bisphenol A (BPA) and styrene. Because these substances are widely used in the manufacture of plastics—BPA in the manufacture of polycarbonate and epoxy resins, and styrene as a building block for other thermoformable polymers— we briefly describe their Prop 65 history.


OEHHA has (to date) twice unsuccessfully sought to list BPA under Proposition 65. The first attempt occurred in 2009, when OEHHA's Developmental and Reproductive Toxicant Identification Committee (DARTIC), which is an advisory panel that helps OEHHA determine whether a chemical is a reproductive toxicant, evaluated whether BPA had been "clearly shown through scientifically valid testing according to generally accepted principles to cause reproductive toxicity." In July 2009, the DARTIC voted against the listing, but left open the possibility for reconsideration if additional relevant data became available. The second attempt took place in 2013, when in January of that year OEHHA released a Notice of Intent to List (NOIL) BPA on Prop 65 as a reproductive toxicant (developmental endpoint), and concurrently proposed to set a MADL for exposures to BPA of 290 micrograms (µg) per day. Although OEHHA finalized the listing in April 2013, a California court required the delisting of BPA pending resolution of still on-going litigation brought by the American Chemistry Council against OEHHA.

This February, OEHHA announced that the DARTIC will again be considering whether to list BPA on Prop 65. There has been a significant amount of new scientific data generated on BPA, including by the U.S. Food and Drug Administration (FDA). The DARTIC will evaluate the data and vote on the listing at its scheduled May 7, 2015 meeting. Although the current exposures to BPA have been repeatedly affirmed as safe by FDA, we consider it possible that BPA will be listed on Prop 65.


OEHHA issued a NOIL for styrene in 2009, but the proposal was later withdrawn based on successful industry litigation in California state courts. In January 2013, OEHHA again proposed the listing of styrene on the basis of the 2011 National Toxicology Program (NTP) listing of styrene in the 12th Report on Carcinogens (RoC) as a substance that is "reasonably anticipated to be a human carcinogen." This notice was withdrawn in March 2013, pending the results of federal litigation and additional peer review of the underlying studies. In February 2015, OEHHA released a second NOIL for styrene, again referencing the NTP RoC. Industry is opposing the listing, and it remains to be seen whether the NTP RoC listing can serve as an adequate basis upon which OEHHA can list styrene.


Until either styrene or BPA is listed on Prop 65, manufacturers need do nothing but continue to monitor the regulatory status of these substances. If a listing does occur, however, we would expect manufacturers to receive many inquiries regarding whether BPA or styrene are present in their products and would require a warning or whether they comply with the safe harbor levels.

Products that require a warning may be considered for deselection by retailers and brand owners. Moreover, the importance of compliance with Prop 65 must be considered in light of how the law is generally enforced. Prop 65 is rather unusual in that it is not enforced by OEHHA, the relevant regulatory authority. Instead, public prosecutors, like the California Attorney General or county District Attorneys, can bring suit. If the prosecutor declines to enforce against an alleged violation, Prop 65 permits private citizens to initiate enforcement actions. Because 25% of any assessed penalty goes to a successful plaintiff, there is a substantial incentive to bring these suits. A number of public interest groups and law firms have systematically engaged in these so-called "bounty-hunter" suits, targeting industries that use a particular chemical in their products for alleged violations. These suits have become a significant nuisance for industry and often force companies into settlement simply to avoid the cost of litigation.

Changes to Prop 65

Having spent some time describing Prop 65, we would be remiss to not point out potential upcoming changes to the law. On January 12, 2015, OEHHA published a Notice of Proposed Rulemaking that would repeal and replace the current Prop 65 implementing regulations. The proposal would make significant changes to the regulations, such as what is considered a "clear and reasonable" warning, requiring certain chemicals to be named in the warning, and establishing a website where OEHHA would post information about products subject to Prop 65 warnings. The comment period for the proposal closes on April 8, 2015, and we would expect additional rounds of revision and comment for the proposed regulations. In the meantime, manufacturers should be aware of further activity regarding the potential listings of BPA and styrene, while tracking these potential major changes to the implementing regulations.

This article was first published in the 2015 second quarter issue of Thermoforming Quarterly, a journal of the Thermoforming Division of the Society of Plastics Engineers. It is reprinted with the permission of the Society of Plastic Engineers.

[1] Codified at § 25249.5 et seq. of the California Health and Safety Code.

[2] Indeed, OEHHA has stated that Proposition 65 "provides a market-based incentive for manufacturers to remove listed chemicals from their products."