Bypass sunscreens with certain ingredients; take a quick shower after swimming or spending time in the sand to wash off potentially deadly bacteria.

4. The wrong sunscreen—The last thing you want when you’re on vacation is tomato-red sunburned skin—or the increased risk of cancer and other health problems that comes with it. But not all sunscreens are created equally. Many sunscreens contain the hormone-disrupting chemicals benzophenone-3 (BP-3), commonly referred to as oxybenzone or 2-hydroxy-4-methoxybenzophenone. Although it’s not completely clear how the hormone-disrupting chemical is affecting humans, animal studies show damage to the liver, kidney, and reproductive organs. The Environmental Working Group recommends sunscreens that contain zinc oxide or titanium dioxide as the active ingredients.

What to do: The sun is strongest between 10 a.m. and 4 p.m., so try not to be in direct sunlight during those times. Use an umbrella and consider wearing very lightweight, SPF-30 beach clothing and swimwear. Look for brands like Solumbra, which don’t coat products in chemicals, but rather keep the sun out with a special fabric weave. When you do use sunscreen, choose brands containing zinc oxide or titanium dioxide that have a white tint that doesn’t absorb easily into your skin. They’re less likely to contain teeny nanoparticles, which could disrupt cell function in microorganisms and people.