A potentially harmful chemical in baby bottles and other household plastics is released 55 times faster after it comes in contact with boiling water, says an alarming new study. Recent research has suggested that bisphenol A (BPA), a chemical found in such everyday items as polycarbonate baby bottles and food packaging, can mimic female sex hormones; if the chemical accumulates in the body, it may heighten the risk of cancer, birth defects, and development disorders. But it hasn’t been clear how much BPA plastic products release in normal use. University of Cincinnati researchers found that when they contained room-temperature fluids or air, plastic bottles released a tiny amount—about half a nanogram—of BPA every hour. But boiling them even briefly dramatically increased the rate of release, so that BPA migrated out of the plastic at 55 times the normal rate even after the boiling water was removed. Though the effects of such amounts of BPA are not known, professor Scott Belcher says, he thinks it’s wise to avoid plastics for serving food or drinks. “That’s been my personal choice,” he says.