In 1977, an expert panel convened by the FDA issued urgently worded advice, saying it was “obligatory” to put a warning on the drug’s label that it could cause “severe liver damage.” After much debate, the FDA added the warning 32 years later. The panel’s recommendation was part of a broader review to set safety rules for acetaminophen, which is still not finished. Four years ago, another FDA panel backed a sweeping new set of proposals  to bolster the safety of over-the-counter acetaminophen. The agency hasn’t implemented them. Just last month, the FDA blew through another deadline.