THE debate seems to resurface every few years. Do some lipsticks contain lead? If so, is the amount so negligible that consumers have nothing to be concerned about? Or will all those years of applying lipstick several times a day add up to a worrisome accumulation of a dangerous substance?

On one side are advocacy groups and doctors who insist that, over time, those who wear lipstick containing lead are at risk of absorbing high levels of a neurotoxin that may cause behavioral, learning and other problems. On the other side are the Food and Drug Administration and outside experts who say that any traces of lead that do exist are too minute to cause harm.