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On Behalf of | Nov 21, 2016 | Wang IP Law Blog

Proposition 65 is officially known as the Safe Drinking Water and Toxic Enforcement Act of 1986 (“Prop 65”). The purpose of Prop 65 is to protect the state’s drinking water sources from being contaminated with chemicals known to cause cancer, birth defects, or other reproductive harm. Also, Prop 65 requires businesses to inform Californians about exposures to such chemicals.

The language of Prop 65 reads:

“No person in the course of doing business shall knowingly discharge or release a chemical known to the state to cause cancer or reproductive toxicity into water or onto or into land where such chemical passes or probably will pass into any source of drinking water…” See CA Health and Safety Code § 25249.5.

“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 a clear and reasonable warning…” See CA Health and Safety Code §25249.6.

Warning Requirements

A business subject to the provisions of Prop 65 is required to warn a person before “knowingly and intentionally” exposing that person to a listed chemical. The warning must be clear and reasonable. This means that it must: (1) clearly communicate that the chemical is known to cause cancer, and/or birth defects or other reproductive harm; and (2) effectively reach the person before exposure. Warning requirements take effect 12 months after the date that a chemical is added to the Prop 65 list.

Pre-approved (“safe harbor”) warnings include the following:

WARNING: This product contains a chemical known to the State of California to cause cancer, birth defects or other reproductive harm.

A business may alter the “safe harbor” language, and add language to explain the warning and inform consumers about how to lessen or avoid the exposure. However, businesses cannot include language that contradicts or dilutes the force of the warning.

Please note that a Prop 65 warning does not necessarily mean a product is in violation of any product-safety standards or requirements. Instead, it serves as a caution sign to California consumers of possible risks associated with the product.


Prop 65 contains the following 6 exemptions:

  1. All federal, state, and local government agencies, as well as entities operating public water systems, are exempt.
  2. Businesses with nine or fewer employees are exempt. Employees are people who provide services for remuneration, including both full-time and part-time employees.
  3. No warning regarding cancer is required if the business can demonstrate that the exposure occurs at a level that poses “no significant risk.” This means the exposure is calculated to result in not more than one excess case of cancer in 100,000 individuals exposed over a 70-year lifetime.
  4. No warning regarding reproductive harm is required if the business can demonstrate that the exposure will produce no observable effect, even at exposures 1,000 times the level in question.
  5. There is an exemption for listed chemicals in food that a business proves to be “naturally occurring” and reduced to the “lowest level currently feasible.” This exemption is to avoid excessive warnings on common food items.
  6. There is an exemption for businesses that can demonstrate that the discharge will not cause a “significant amount” of the listed chemicals to enter any drinking water source, and complies with all other applicable laws, regulations, permits, requirements, or orders.


Enforcement is carried out through civil lawsuits brought by the CA Attorney General, or by a district attorney or city attorney of a city with a population exceeding 750,000. The Attorney General decides whether to file suit on a case-by-case basis. Among the factors considered are the seriousness of the violation and whether it presents a risk to public health; how widespread the violation is; and whether the case presents new issues of law or science that should be resolved on a statewide basis.

Private parties acting in the public interest can also bring Prop 65 lawsuits, but only if they provide at least 60 days notice of the alleged violation to the business, as well as to the Attorney General and the appropriate district attorney and city attorney. The notice must provide adequate information about the alleged violation and comply with the requirements specified in the regulations.

If a business is found to be in violation of Prop 65, a court may order the business to stop committing the violation. The business is also subject to civil penalties of up to $2,500.00 per day for each violation.

Response To Notice

Businesses are allowed to reformulate a product rather than provide a warning. Businesses often reformulate by removing a listed chemical or reducing its concentration so that any exposure is below the threshold.

Once a business receives a notice, the business should consider taking the following steps: (1) promptly contact the noticing party to discuss the claims of violation and obtain any testing or data the noticing party is willing to provide to evaluate whether the claim is justified; (2) conduct laboratory product testing and/or obtain an exposure assessment to assess the validity of the plaintiff’s claim; and (3) if the business believes the claim may be valid, cease sale of the product, instruct retail customers to stop selling the product, recall the product, and/or provide proper warnings for the product.