US California Proposition 65 (Safe Drinking Water and Toxic Enforcement Act)

California's Proposition 65 (the Safe Drinking Water and Toxic Enforcement Act) requires warning labels on products containing any of roughly 900-plus chemicals known to cause cancer or reproductive harm. This proposed revision tightens the requirements for the "short-form warning" that has been widely used on product packaging. Under the current rule, a warning can be given without naming a specific chemical; the revision would require that at least one listed chemical be named to improve transparency. It would also tighten consistency requirements for warnings shown in online and catalog sales.

Under California's Proposition 65 (the Safe Drinking Water and Toxic Enforcement Act), "carbon black (airborne, unbound particles of respirable size)" is listed as a carcinogen. Carbon black that is fully bound within a product matrix — such as rubber, plastic, or paint — is not covered, but products involving fine powder toner, 3D-printing powder, or sanding and machining that can release airborne particles fall within scope and require a consumer warning.

California's Proposition 65 (the Safe Drinking Water and Toxic Enforcement Act of 1986) requires businesses to provide a "clear and reasonable warning" for chemicals listed on the state's own official list of carcinogens and reproductive toxicants when they may result in significant consumer exposure. Enacted by voter initiative in 1986, the law has operated continuously and consistently for nearly four decades, giving it a robust legal framework that is not directly affected by changes in federal administration. The list of covered substances is updated on an ongoing basis by the state's Office of Environmental Health Hazard Assessment (OEHHA); in addition to more than roughly 900 already-listed chemicals, recent years have seen continued additions and standard revisions covering PFAS-related substances (PFOA, PFOS, PFHxS, PFNA, etc.), certain flame retardants, and plasticizers (phthalate esters). The law's most distinctive enforcement feature is that, in addition to public enforcement by the state Attorney General and district attorneys, private citizen suits brought by individuals and law firms acting "in the public interest" (the so-called 60-day notice and bounty-hunter litigation mechanism) are extensively and actively pursued. Several thousand 60-day notices are issued annually, generating a structure of high-value settlements (covering attorneys' fees and civil penalties), and due diligence on chemicals contained in products, together with warning-label compliance practice, remains one of the most critical risk management items for global companies entering the California market.