A chemical called octyl methoxycinnamate, or OMC, is found in more than 90 percent of sunscreen products and filters out damaging ultraviolet rays. But Norwegian scientists found that when they combined OMC in the lab with simulated sunlight, it killed animal cells, prompting suspicion on what it may do to humans.

The troubling finding, according to these scientists, is that OMC itself is a very important component in sunscreen. Yet, when it is combined with light, the byproduct is twice as toxic than OMC alone.

Some American scientists say this study should not discourage patients from using sunscreen. They say that you’re putting sunscreen outside of skin on the dead layer of surface, therefore not penetrating or harming the skin at all. Another reason to hold on to your bottle of sunscreen is that this is only a lab study. Even the Norwegian scientists insist that this should only raise a “small alarm.” People are more protected with sunscreen than without.

The American Cancer Society estimates that there are one million new cases of skin cancer diagnosed every year, resulting in nearly 10,000 deaths.