Accurately disclosing listed substances within sold products is the best way for companies seeking to comply with the Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65) to avoid litigation. Prosecution over Proposition 65 is usually centered on cases where exposure to substances is not accounted for with labels. Law firms seeking to monetize Proposition 65 prosecution (a.k.a. "bounty hunter law firms") typically scan retail shelves looking for products that use materials that have a high level of risk for containing listed substances (e.g. lead in brass), but lack labels. If you are disclosing instances where listed substances occur in your products, you are providing your customers with the information they need to comply with the law. Maintaining a paper trail for the information you provide to your downstream customers is important.
In cases where a product may cause exposure to multiple different listed substances, the relevant requirement is that all exposure risks for listed substances are accounted for with consumer product exposure warnings. ("Consumer product exposure warnings" usually refers to warning labels but sometimes can mean pop-up windows in e-stores or other specific warnings based on special product types.) If a product were to contain multiple substances that cause cancer and multiple substances that cause birth defects, as long as one of each is disclosed with the appropriate warning text, there should be no risk of litigation, as there is no requirement to disclose all carcinogenic substances or all birth defect-causing substances in warning labels.
Article is current as of 2019-08.