Watch out for sunscreens that contain a cancer-causing chemical - experts say there's no safe level of exposure

• Some sunscreen batches have been found to contain benzene, a cancer-causing chemical.
• Long-term benzene exposure has been linked to a five-fold increase in leukemia risk.
• The lab that identified the contaminated batches is asking the FDA to recall the products.

An independent laboratory is calling for 40 batches of sunscreen products to be pulled from shelves after they were found to contain significant amounts of benzene, a known carcinogen.

Benzene has been linked to increased cancer risk since 1977, when a landmark study found workers who were exposed to benzene over nine years had a five times higher than normal risk of leukemia. Nowadays, the chemical is most commonly found in cigarette smoke and gasoline fumes.

Although the small amounts found in the sunscreen products are far less toxic in comparison, experts say any benzene exposure poses a health risk.

"There's no such thing as a safe level of exposure, and that's especially true for children," Philip Landrigan, director of the Global Public Health Program and Global Pollution Observatory at Boston College, told Bloomberg.

Valisure, a pharmaceutical testing company, tested 294 batches of sunscreen from 69 different brands. The lab is asking the Food and Drug Administration to recall 40 batches from 10 different brands including Neutrogena, Banana Boat, and CVS Health.

David Light, Valisure's founder, told Bloomberg he thinks the problem is likely rooted in specific batches, not brands. Benzene is often used as an industrial solvent, so it's possible the sunscreen makers were unknowingly using contaminated solvents in some of their products.

"In this case it really seems to be a manufacturing contaminant problem, not an inherent problem with sunscreen," Light told CNET. "People should still continue to use sunscreen, I think, is an important message to get across."