As part of the law, businesses selling products to people in California must provide “clear and reasonable warnings” before knowingly exposing people to any chemical on the list, unless the expected level of exposure would pose no significant cancer risk. This warning is often in the form of a label on the product or its packaging.

The law defines “no significant risk” as a level of exposure that would cause no more than 1 extra case of cancer in 100,000 people over a 70-year lifetime. So a compound can be unlabeled if a person exposed to the substance at the expected level for 70 years is estimated to have a 1 in 100,000 chance or less of getting cancer due to that exposure. The law also has similar strict cutoff levels for birth defects and reproductive harm.

Businesses decide whether to put warning labels on their products based on their knowledge of the types of chemicals in them. Manufacturers are not required to provide the OEHHA with any information about the products. That means the OEHHA doesn’t know which chemical the warning refers to, how exposure could occur, or how much of the chemical a consumer is likely to be exposed to. All of these factors are critical when determining how much risk it might pose. The OEHHA cannot offer information to help consumers figure out what the potential risk is and how to avoid it. These kinds of details can only come from the product’s manufacturer.