California’s Proposition 65 law benefits all Californians by reducing their exposure to chemicals that are on the Proposition 65 list for cancer, birth defects or other reproductive harm.
Proposition 65 encourages businesses to reformulate their products to remove listed chemicals. In some cases, businesses proactively make these changes. In other cases, the change results from an enforcement action brought under Proposition 65.
Studies published in 2024 and 2025 confirm Proposition 65’s ongoing, positive impact in encouraging businesses to reformulate their products to remove toxic chemicals on the Proposition 65 list. One study found that Proposition 65 “prompted manufacturers to deselect specific toxic chemicals, whether by substituting other chemicals, reducing the concentration of the listed chemical, or redesigning products to obviate the need for the toxic chemical’s function.” This change was most pronounced for the Proposition 65-listed chemicals Bisphenol A, chloroform, toluene, and three phthalates. Another study confirmed these findings in interviews with manufacturers across many business sectors.
In sectors from electronics to healthcare, our in-depth interviews confirmed that companies frequently reformulate products to remove Proposition 65-listed chemicals or request alternatives from suppliers.
The removal of toxic chemicals from consumer products has far-reaching effects. Journalists from the Oakland-based 99% Invisible radio podcast team who investigated Proposition 65’s history and impact found it plays an important role in protecting consumers in the United States. “When companies remove dangerous chemicals to meet Prop[osition] 65 guidelines,” the team concluded, “it’s not just Californians who benefit from that. The same products are made safer for the rest of the country as well. And because the state of California has the 5th biggest economy in the world, producers globally are pushed to do the same.” Indeed, in one study, researchers found that more than half the manufacturers they interviewed who reformulated their products for sale in California also sold the reformulated products in other states.
By encouraging this kind of reformulation, Proposition 65 contributes to a broader reduction in consumer exposure to a number of listed chemicals, often in ways that the average consumer may not easily recognize.
Curious about how Proposition 65 has affected you? Proposition 65 enforcement actions have led to the removal of toxic chemicals from familiar consumer goods, including food and beverages, dietary supplements, personal care products, and children’s products. The law has also spurred significant reductions in air emissions of listed chemicals in California’s neighborhoods.
Interested in further reading about the impacts that Proposition 65 has had on Californians? Consider reading the following articles, some of which are quoted above:
- California Told Companies to Label Toxic Chemicals. Instead They’re Quietly Dropping Them – Scientific American (May 2025)
- California’s Scary Product Warning Labels Might Be Working, Study Says – The New York Times (February 2025)
- Prop 65 gives toxic ingredients the boot – UC Berkeley Press (February 2025)
- California disclosure law prompting manufacturers to shift away from toxic compounds: Study – The Hill (February 2025)
- How a Right-to-Know Law Shifts Industry away from Chemicals of Concern: The Case of California’s Proposition 65 – American Chemical Society (February 2025)
- A Wide Reach: California’s Prop 65 and Reduced Chemical Exposures Across the United States – Environmental Health Perspectives (December 2024)
- Controversial Prop. 65 warning labels about toxic chemicals are effective, study says – LA Times (November 2024)
- Trends in NHANES Biomonitored Exposures in California and the United States following Enactment of California’s Proposition 65 – Environmental Health Perspectives (October 2024)
- WARNING: This Podcast Contains Chemicals Known to the State of California to Cause Cancer or Other Reproductive Harm – 99% Invisible (March 2024)
- The Hidden Success of a Conspicuous Law: Proposition 65 and the Reduction of Toxic Chemical Exposures – SSRN (December 2020)