system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 why do some (most) products say "this product has been known in the state of California to cause cancer?

Why just California?
gpt
California has a state law (Proposition 65) that was passed 30 years ago or so that requires companies to warn consumers if they're selling them any product that contains certain chemicals.

The intentions were good - all of these chemicals might be carcinogenic. Unfortunately, 99% of the time they're perfectly safe when used as intended.

The problem is that the law has stiff penalties for failing to warn consumers, but there's absolutely no penalty for issuing a warning that isn't needed. So most companies add the warning to *everything* that might contain even trace amounts of any of those chemicals, just to be safe.

Unfortunately it just means that those warnings are useless.