Chances are you've heard about "reef-safe sunscreens" and the importance of using sunblock that doesn't contain harmful chemicals.
But which chemicals are harmful? What does that even mean?
In May of this year, Hawaii passed a bill that prevents the sale of sunscreen containing UV-filtering ingredients, like oxybenzone (the most common compound found in nearly 3,500 sunscreens worldwide), octinoxate (even more toxic that oxybenzone, but usually found in lower concentrations), and octocrylene. These are the dangerous chemicals have been linked to coral bleaching.
A good rule of thumb: the simpler the formula, the better. A great alternative to using sunscreen when diving or snorkeling is to wear a long-sleeved sun shirt or rash guard with a UPF (UV-protective fabric) of 50-plus. It should have a crew neck and ideally will have a thumbhole to hold the sleeve over the top portion of your hands. More coverage, less sunblock.