California Prop 65



Proposition 65 – Safe Drinking Water and Toxic Enforcement Act – is a California state regulation enacted in November 1986.

The regulation requires businesses to provide warnings on products or in establishments about significant exposures to chemicals, listed under Proposition 65, that cause cancer, birth defects, or other reproductive harm. The intent is that the public can make informed decisions about their exposure to these chemicals.

In addition, proposition 65 prohibits California businesses from knowingly discharging significant amounts of listed chemicals into sources of drinking water. 

Prop 65 Frequently Asked Questions

What does a Proposition 65 Warning Mean?

You may see a warning placed on a product label or posted or distributed at a workplace, business, or in rental housing. If a warning is provided, the business issuing the warning is aware or believes that it is exposing individuals to one or more Proposition 65-listed chemicals.

What Chemicals are included in the Proposition 65 List?

The California Office of Environmental and Health Hazard Assessment (OEHHA) publishes the Proposition 65 list of chemicals known to cause cancer, birth defects or other reproductive harm. Since the regulation’s inception in 1986, the list has grown to include approximately 900 chemicals.

There is a wide range of naturally occurring and synthetic chemicals including additives or ingredients in pesticides, common health products, food, drugs, dyes, or solvents. These may also be used in manufacturing, construction, or they may be byproducts or chemical processes, such as motor vehicle exhaust. OEHHA Prop 65 Chemicals List

Who is Responsible for Deciding if a Warning is Necessary?

The Proposition 65 regulation leaves the determination of providing a warning to the business. The warning regulation does not explain how a business can assess if a warning is appropriate and it does not mandate businesses to perform testing. Testing for all, approximately 900, chemicals under Proposition 65 would not be obtainable.

To try and provide further guidance, the OEHHA sets safe harbor levels and safe use determinations on Proposition 65 exceptions.

Safe Harbor Levels include No Significant Risk Levels for cancer-causing chemicals and Maximum Allowable Dose Levels for chemicals causing reproductive toxicity. Several Proposition 65 chemicals have Safe Harbor Levels. Exposure levels and discharges to drinking water sources below the safe harbor levels are exempt from requirement of Proposition 65. There is no regulatory guidance on assessing safe harbor levels. The responsibility to determine if the exposure level falls below the safe harbor levels lies with the business.


OEHHA Prop 65 Chemicals List
OEHHA Notice of Adoption of Article 6 
OEHHA Modified Article 6 Q&A for Businesses
WQA Proposition 65 Factsheet
WQA Radio Episode 71 (05/31/2018) – Interview with CA Lobbyist Randy Pollack on Proposition 65
WQA Radio Episode 77 (07/11/2018) –  Regulatory Update with Kathleen Fultz on Proposition 65 (at 9:42 mark)