BOSTON -- A new study shows many sunscreens may not protect your skin, and some are even dangerous to your health. NewsCenter 5's Heather Unruh took a closer look at the study on Tuesday.

There is a new warning as you lather on the sunscreen this summer. A new study suggests some top sunscreens may be a hazard to your health.

"It's kind of scary," said Kaeelia O'Donnell, of Dorchester.

"You send your babies out, and you think they're protected," said Cynthia Lopes, of Dorchester.

But according to the Environmental Working Group, some sunscreens are not protecting users. Researchers checked 800 different brands of sunscreen against some 400 other studies. Fifty-four percent of the brands tested contained ingredients that broke down in the sun. The study found 13 percent blocked UVB Rays but not the harmful UVA rays.

"A lot of the sunscreens don't have really good UVA protection," said Dr. Hensin Tsao, the director of the melanoma genetics program at Massachusetts General Hospital.

Some products contained questionable chemicals, such as oxybenzone, which has been linked to cancer.

Three sunscreens that received good ratings are all for babies. They included the Blue Lizard Australian Suncream SPF 30/Baby, California Baby Water-Resistant Hypo-Allergenic Sunscreen SPF 30-plus and Aveeno Baby Sunblock Lotion Continuous Protection SPF 55.

Top brands that made the worst list include: Coppertone Sport Sunblock Lotion SPF 15, Neutrogena Healthy Skin Face Lotion SPF 15 and Kiss My Face Everyday Moisturizer SPF 15.

Tsao said don't toss out those top brands just yet, because more studies need to be done. In the meantime, he said, become a savvy sunscreen shopper.

"Most sunscreens will break down over time in the sun, and because of that, you have to reapply. Many of them are not waterproof or sweatproof, so you have to buy ones that state waterproof or sweatproof," he said.

"I see the dermatologist twice a year, and I go by his recommendations. I make sure everybody puts sunscreen on, and I feel good about it," said Barbara Peterson, of Milton.