NEXT TIME you liberally smear suntan lotion on your body and linger too long in the sun, beware: Sunscreens are not sunproof, say scientists.

According to US epidemiologists Cedric and Frank Garland, though the lavish use of sun lotions blocks out the most damaging sun rays and prevents sunburn, it also allows fair-skinned people to stay much longer in the sun. The scientists say the consequent overexposure to radiation can penetrate their sunscreen, and promote a deadly form of skin cancer called melanoma, which threatens to kill 7,000 Americans this year.

Though several experts are sceptical about the Garlands' conclusions, the US Food and Drug Administration has asked sunscreen manufacturers to put warnings on their lotions about the harmful effects of overexposure to the sun.