Traces of a chemical tied to blood cancers including leukemia have been detected in dozens of popular sunscreens and after-sun products, according to tests conducted by online pharmacy and lab Valisure. Benzene, a known carcinogen, was found in 78 of nearly 300 sprays and lotions tested — about 27% — including products sold by Banana Boat and CVS, according to Valisure. In a petition, the company has asked the FDA to recall these contaminated batches. The regulating body is reviewing the claim.