We are assessing the effectiveness of California's Proposition 65 law in lowering exposures to chemicals that cause breast cancer and what actions policymakers can take to protect public health.
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California’s Safe Drinking Water and Toxic Enforcement Act of 1986 (commonly known as Proposition 65) requires the state of California to publish a list of chemicals that cause cancer, birth defects, or reproductive harm. The law also requires businesses to notify California consumers, and in some cases workers, if products contain significant amounts of one or more of the chemicals that appear on the Proposition 65 list. We are investigating whether the law has resulted in lower exposures to these chemicals and identifying further actions that policymakers can take to protect public health under the law.

Our project addresses the following questions: 1) Have levels of breast cancer-related chemicals in Californians’ bodies changed since the chemicals were included in Proposition 65?; 2) How have consumers and workers responded to Proposition 65 warnings?; and 3) How have businesses changed their products or manufacturing practices in response to Proposition 65?

News & Updates


New study by Silent Spring Institute and UC Berkeley shows people exposed to multiple chemicals that can cause cancer, birth defects, or reproductive harm.