Businesses are required to provide a "clear and reasonable" warning before knowingly and intentionally exposing anyone to a listed chemical, unless the business can show that the anticipated exposure level will not pose a significant risk of cancer or is significantly below levels observed to cause birth defects or other reproductive harm.
This warning can be given in several ways, such as by labeling a consumer product, posting signs at the workplace, distributing notices at a rental housing complex, or publishing notices in a newspaper. The requirement to provide warnings takes effect one year after a chemical is added to the list.
Proposition 65 also prohibits companies that do business within California from knowingly discharging listed chemicals into sources of drinking water. Once a chemical is listed, businesses have 20 months to comply with the discharge prohibition.
Businesses with less than 10 employees and government agencies are exempt from Proposition 65’s warning requirements and prohibition on discharges into drinking water sources.
Businesses are also exempt from the warning requirement and discharge prohibition if the exposures they cause are so low as to create no significant risk of cancer or are significantly below levels observed to cause birth defects or other reproductive harm.
Using its knowledge of its business operations and the chemicals it uses, a business can review the Proposition 65 list to determine whether its operations or products are likely to expose people in California to any listed chemicals. Depending on the level of exposure, the business may be required to provide a warning for those exposures. A business that determines it is causing exposures to a listed chemical may be able to use OEHHA’s safe harbor numbers to determine if it needs to provide a warning.
To guide businesses in determining whether a warning is necessary or whether discharges of a chemical into drinking water sources are prohibited, OEHHA has developed safe harbor levels. A business has “safe harbor” from Proposition 65 warning requirements or discharge prohibitions if exposure to a chemical occurs at or below these levels.
These safe harbor levels consist of No Significant Risk Levels for chemicals listed as causing cancer and Maximum Allowable Dose Levels for chemicals listed as causing birth defects or other reproductive harm. OEHHA has established over 300 safe harbor levels to date and continues to develop more levels for listed chemicals.
If OEHHA has not established a safe harbor level for a chemical, businesses that expose individuals to that chemical would be required to provide a Proposition 65 warning, unless the business can show that the anticipated exposure level will not pose a significant risk of cancer or reproductive harm. OEHHA has adopted regulations that provide guidance for businesses in calculating their own level in the absence of a safe harbor level. Regulations are available at Article 7 and Article 8 of Title 27, California Code of Regulations.
Determining anticipated levels of exposure to listed chemicals can be very complex. Although a business has the burden of proving a warning is not required, a business is discouraged from providing a warning that is not necessary and instead should consider consulting a qualified professional if it believes an exposure to a listed chemical may not require a Proposition 65 warning.