With hundreds of sunscreens on the market, choosing one can often be overwhelming.

When we do pick one, we expect it to protect us from the sun’s harmful rays, but a recent study by the Environmental Working Group found many do not.

The group tested 785 sunscreen products with an SPF rating of 15 or higher and found 84 percent of those offered inadequate protection from the sun.

Those findings weren’t a big surprise to Dr. John Kirkwood. He’s a nationally known skin cancer researcher at the University of Pittsburgh Cancer Institute.

Kirkwood said, “It's a serious fallacy to think that if you put on sunscreen you can go out in the sun and be safe. There is no safe sunbathing.”

So how can consumers pick the best sunscreen?

Kirkwood said, “A savvy person should look for sunscreen that blocks both UVA and UVB.”

Those are the ultra violet rays that penetrate the skin and cause cancer.

SPF numbers only tell you what the sunscreen’s UVB protection is. To ensure you're protected from UVA rays, make sure the sunscreen contains one of the following active: avobenzone, zinc oxide, titanium dioxide or mexoryl.

Also, beware of claims a sunscreen is waterproof.

All sunscreens can wash off. Some may be more water resistant than others, but there is no test a product must pass to make that claim.

In fact, the Food and Drug administration still has no comprehensive sunscreen standards. Consumers have to know what to look for in a sunscreen in order to best protect their skin.

Kirkwood said the best protection is to avoid the sun when possible. Especially if you have fair skin and light eyes, that puts you at a higher risk of developing skin cancer.

If you have to be outside Kirkwood said, “Use a barrier, clothing, parasols, to be under the trees. Only when you have to be out should you be sure you have sunscreen and sunblock on.”

If you can't cover up look for a sunblock, not a sunscreen there is a difference.

Sunscreen contains materials that act as filter to allow a certain range of UV light to be absorbed into the skin. Sunblock contains metallic materials that reflect and scatter the UV light and acts a wall between the sun and your skin. So what do you look for on the label of a sunblock?

Kirkwood said, “The titanium oxide and zinc oxide are blocks, so they are more effective sunscreens."

According to Consumer Reports, “Consumers might be getting less than half the sunburn protection shown on labels because they don’t apply enough.”

Adults need to use 2 to 3 tablespoons of sunscreen and reapply it every two hours. SURVEYS AND RELATED LINKS Vote: Who Burns More? Men or Women?Sunburns By StateHow To Spot A Suspicious MoldEnvironmental Working Group Sunscreen StudySun Safety IQ QuizSurvey Rates Most and Least Sun Smart CitiesHow Sun Smart Are You: Take The SurveyAmerican Cancer Society: Skin Cancer