Acetaminophen, the active ingredient in Tylenol and hundreds of both prescription and over-the-counter pain relievers, has been under study as a potential cause of cancer.
State regulators have looked at 133 peer-reviewed studies, some of which found a link to some forms of cancer. Other studies found no such link.
A California law, Prop 65, requires the state to designate substances it believes can cause cancer or reproductive toxicity. Over 900 chemicals have been so labeled and a public hearing is expected to be held to discuss Acetaminophen after a public comment period ends on January 27th.
The designation would not take the pain-killer off the market and federal officials warned that California making the designation would be illegal. However, the state might still take action – under consideration since 2011 – on its own.