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Assessing Risk

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Assessing Risk: Proposition 65 Educational Information

What Is Proposition 65?

The Safe Drinking Water and Toxic Enforcement Act of 1986, also known as Proposition 65, requires the Governor of California to publish a list of chemicals known to cause cancer, birth defects, or other reproductive harms. The Office of Environmental Health Hazard Assessment (OEHHA) coordinates research related to the listing of chemicals, as a division of the California Environmental Protection Agency (CalEPA). Prop. 65 imposes controls on listed substances to help protect the California public from exposure via drinking water, in the workplace, and from consumer products generally.

In addition to prohibiting businesses from knowingly discharging listed chemicals into drinking water sources, Prop. 65 requires businesses to post a "clear and reasonable" warning that consumers may be exposed to a listed chemical.

For the listing of a carcinogen, OEHHA uses a 1 in 100,000 risk level as a benchmark for determination of an appropriate exposure value that will protect public health. This exposure value termed a No Significant Risk Level (NSRL) is the level of exposure to the substance (generally in micrograms) per day over a lifetime that will not result in an elevated cancer risk. In other words, if 100,000 individuals were exposed to a substance at the NSRL for their lifetimes, only one individual would be expected to have a cancer attributable to that substance.

For the listing of chemicals as reproductive or developmental toxicants, OEHHA uses a Maximum Allowable Daily Level (MADL) representing the No Observable Adverse Effect Level (NOAEL) times a factor of 1,000 for added protection. The NOAEL is the level (generally in micrograms) per day of the substance, which has been shown either through animal or human studies to present no adverse reproductive or developmental effects.

How it Works

Any individual or organization in California may contribute to the listing of a substance under Prop. 65. This can be accomplished through written or verbal comments to OEHHA during designated periods of public comment on considered substances. In addition, the public may sue private companies to provide warning labels on products containing a listed substance, or on the site where exposure may occur.

If a company can prove that their facility or product does not expose the public to a listed substance in excess of the NSRL or MADL, no warning statements are required. However, if a product or facility is found to expose the public to a listed substance at a level exceeding the NSRL or MADL, they may face severe financial penalties. These fines offset the legal costs for plaintiffs, and are distributed to public interest organizations (such as CETOS) that are working to better protect public health from exposure to substances that may cause cancer or adverse reproductive/developmental effects.

What CETOS does

Our organization consults with members of the public, other public interest organizations, and plaintiff attorneys (generally representing the People of California) involved with Prop. 65 related litigation. CETOS conducts risk assessments, and offers scientifically credible evaluations of the public health threat posed by listed and yet to be listed substances. Additionally, through independent risk evaluations, CETOS works to identify products that have yet to be recognized as posing a significant hazard.

Some of the cases we have worked on:

  • Southern California fish contaminated with Mercury, PCBs & DDT
  • Lawn & garden fertilizers/supplements containing Arsenic, Lead & Cadmium
  • Public & private drinking water systems contaminated with MTBE, Malathion & Diesel
  • Lead contamination of water pipes, light bulbs, crystal ware, stained glass, roofing tiles & car batteries
  • Herbal and dietary supplements containing Mercury, Cadmium, Arsenic & Lead
  • Tobacco Smoke contamination of hotel facilities
  • Asphalt & Creosote release from road paving operations
  • Plastic water pipes leaching DEHP

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