California’s Proposition 65 – formally known as the California Safe Drinking Water and Toxic Enforcement Act – has been around since 1986, and it is still critically important when it comes to warning labels for products sold in California.

The proposition protects the state's drinking water sources from being contaminated with chemicals known to cause cancer, birth defects or other reproductive harm, and requires businesses to inform Californians about exposures to such chemicals. Proposition 65 requires the state to maintain and update a list of chemicals known to the state to cause cancer or reproductive toxicity.