The federal Food and Drug Administration is ordering sunscreen manufacturers to change the way they label their products to prohibit the use of certain marketing terms. The rules are also designed to clear up confusion about the meaning of “sun protection factor,” or SPF, and other terms like “waterproof.”

SPF measures a sunscreen’s ability to prevent sunburn, which is caused by ultraviolet B (UVB) light. Scientists now also know that ultraviolet A (UVA) is a major cause of aging and also contributes to skin cancer. But SPF labels on sunscreen do not currently address the risks of UVA light.

“Consumers might have a misinterpretation, not realizing that they’re not being fully protected,” says Michael Hansen, a senior scientist at Consumers Union, a group that has been pushing the FDA for years to require better sunscreen labels.

The new FDA rule should help by requiring any sunscreen that calls itself “broad spectrum” to protect against both UVB and UVA. Some people who work regularly in the sun think that’s a good idea.

“I already have some wrinkles on my forehead from doing six summers of this,” says Mohican pool manager Ellen Hearle, age 21, outside of Washington, D.C.

Hearle also says she would like a sunscreen that did not wash off in the pool.

“I definitely need something that’s waterproof, because we’re going in the water a lot,” she says.

Reading The Labels

The FDA says there’s no such thing as a waterproof sunscreen. They all wash in the pool, or with sweat. Starting next summer, the best a label will be able to claim is that a sunscreen is water resistant.

That leaves the question of how to avoid cancer-causing rays while manufacturers retool sunscreens and labels. David Leffell, professor of dermatology at Yale University, has a few recommendations for this summer.

“Number one, make sure that your sunscreen has an SPF of 30,” Leffell says.

Number two on Leffell’s list: “Make sure that it says broad spectrum,” protecting against both UVA and UVB. For UVA, Leffell says to look for products that contain zinc oxide or avobenzone.

His third recommendation: “Whether the label says sweatproof or waterproof, you should reapply every couple of hours while you’re active outdoors anyways, because sunscreen does wear off.”

Sun-Protective Clothing

Leffell adds it is also possible to be well protected without using any sunscreen at all.

“A white T-shirt gives you a sun protection factor of 6, which frankly is not very helpful at all,” he says. “But there are so many products out there: sun-protective clothing products that are rated for their sun protection, and don’t look like prison uniforms anymore. They actually look like real clothing.”

And protective clothing that looks like real clothes are a good thing, because skin cancer rates in young people are on the rise. Leffell is seeing cases of young women in their twenties developing skin cancer, “which used to be unheard of,” he says.

So although sunscreens are less than perfect, there are still very good reasons to use them.

Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.