Editor’s Note: This post has been updated to reflect 2018 revisions to the Prop 65 regulations, which for the first time allocated responsibility for compliance within the supply chain. These revisions place the primary responsibility for compliance on manufacturers, distributors, and importers, while limiting the circumstances in which retail sellers are responsible for providing consumer product warnings.

To the average person in California, if they know anything about Proposition 65 at all, it is usually because they have a seen a warning sign in a bar or at a store. In most instances, after seeing the sign, they likely kept drinking or kept shopping.

Back in 1986, however, Californians’ concern over toxic chemicals in the environment, workplaces, and consumer products was a hot button issue because it was much more difficult to get information about everyday exposure to chemicals. As a result, 63% of California voters approved Proposition 65, and shortly thereafter, the ballot initiative became codified in the California Health & Safety Code as the Safe Drinking Water and Toxic Enforcement Act of 1986 (Health and Safety Code § 25249.5 et seq). The following sections provide an overview of Proposition 65. Detailed discussions will follow in upcoming posts.


Prop. 65 prohibits a person from knowingly discharging chemicals known to cause cancer (carcinogens) or reproductive harm in a place where those chemicals are likely to end up in drinking water. We will skip the drinking water part, as it is relatively straightforward and not controversial.

The statute also prohibits a person from knowingly and intentionally exposing any person to carcinogens or reproductive toxins without first providing a warning, if the exposure is significant. This is the key provision of Proposition 65 that gives retailers, manufacturers, and vendors of consumer products heartburn, and on which we will focus this series.


Prop 65 authorizes both public and private enforcers to bring enforcement actions against parties alleged to have failed to provide required warnings to the tune of up to $2,500 per day per violation in civil penalties. Under California’s Private Attorney General Statute (Code of Civ. Proc. § 1021.5), private enforcers may also seek attorney fees for “enforcement of an important right affecting the public interest” if the action results in a “significant benefit” to the public.

Procedural requirements

The statute contains a number of procedural requirements that public and private enforcers must follow in bringing an enforcement, including the infamous 60-day Notice requirement and settlement procedures, which we will discuss in upcoming posts.

The list of chemicals

The statute directs the Governor to publish the list of carcinogens and reproductive toxins that require a warning if causing a significant exposure, and to revise it at least once per year. Chemicals can get on the list four ways, including (1) determination by designated scientists and health professionals, (2) identification by specified “authoritative bodies,” such as the US EPA, (3) identification by a federal or state agency as requiring warning labels (e.g., FDA drug labeling requirements); and (4) identification as a hazardous substance under the California Labor Code.


Proposition 65 provides three exemptions for the warning requirements. First, it exempts any exposure that is already governed by a federal warning law that preempts Prop 65. Second, it exempts exposures that take place within 12 months of a chemical being added to the list. Third, it exempts exposures that are not significant (no significant risk assuming lifetime exposure at the level in question for substances known to the state to cause cancer and no observable effect assuming exposure at one thousand (1000) times the level in question for substances known to the state to cause reproductive toxicity).

In addition, Prop 65 excludes “any person employing fewer than 10 employees” from the warning requirement.

Allocation of responsibility

Prior to August 2018, any party in the supply chain could be held liable for failing to provide a warning. But revisions to the warning regulations, effective August 2018, allocate responsibility for warnings primarily to manufacturers, distributors, and importers (together, suppliers), with retailers responsible only in specified circumstances.

Suppliers can meet their warning obligation “either by affixing a label to the product bearing a warning…, or by providing a written notice directly to the authorized agent for a retail seller.”  27 Cal. Code Regs. § 25600.2.

Retailers are responsible for providing a warning (i.e., may be liable in an enforcement action) when:

  • The retailer sells the product under its private label or a brand or trademark owned by the retailer.
  • The retailer has knowingly and intentionally introduced a listed chemical into the product, or caused a listed chemical to be created in the product.
  • The retailer has covered, obscured, or altered a warning label.
  • The retailer has received warning information and materials from the supplier and does not post them—note that consent for the warnings from the retailer is not required; the supplier need only send the information to the retailer’s authorized agent.
  • The retailer has actual knowledge of the potential product exposure requiring the warning, and the suppliers are exempt and have no place of business in California or agent for service of process in California.

A retailer can modify this allocation by contract, requiring its suppliers and other vendors to provide a warning, as long as a required warning is ultimately provided.


The statute directs the Governor to appoint an agency to implement Proposition 65. The California Office of Environmental Health Hazard Assessment (OEHHA – pronounced “o-wee-ha” or “o-hee-ya”), part of CalEPA, is tasked with implementing Prop 65. To do so, it has promulgated a series of regulations and issued various guidance documents that more fully explain Proposition 65 compliance. OEHHA also publishes the list of chemicals.