WASHINGTON — After 33 years of consideration, the Food and Drug Administration took steps on Tuesday to sort out the confusing world of sunscreens, with new rules that specify which lotions provide the best protection against the sun and ending claims that they are truly waterproof.
The F.D.A. said sunscreens must protect equally against two kinds of the sun’s radiation, UVB and UVA, to earn the coveted designation of offering “broad spectrum” protection. UVB rays cause burning; UVA rays cause wrinkling; and both cause cancer.
The rules, which go into effect in a year, will also ban sunscreen manufacturers from claiming their products are waterproof or sweatproof because such claims are false. Instead, they will be allowed to claim in minutes the amount of time in which the product is water resistant, depending upon test results.
And only sunscreens that have a sun protection factor, or SPF, of 15 or higher will be allowed to maintain that they help prevent sunburn and reduce the risks of skin cancer and early skin aging.
The rules have been under consideration since 1978, when “Boogie Oogie Oogie” was a hit on the radio and most beach lotions were intended to encourage tanning, not protect against it. But federal regulators said they had yet to decide whether to end an SPF arms race in which manufacturers are introducing sunscreens with SPF numbers of 70, 80 and 100 even though such lotions offer little more protection than those with an SPF of 50.
Still, dermatologists said they were thrilled.
“Now, we’ll be able to tell patients which sunscreens to get,” said Dr. Henry W. Lim, chairman of dermatology at Henry Ford Hospital in Detroit and a spokesman for the American Academy of Dermatology.
The rules will transform the $680 million domestic market for sunscreens, which has been growing rapidly because of an aging population and growing worries about skin cancer. And the final regulations are a stark change from a proposal the agency released in 2007, which would have created a star-based system for UVA protection. Under that system, sunscreens would have provided an SPF number for UVB protection and one to four stars for UVA protection.
The agency received more than 3,000 comments on that proposal, with many asserting that allowing products to offer differing levels of protection against UVB and UVA rays would be confusing. So the agency ditched the stars and instead will tell manufacturers that if they wish to label their products as offering “broad spectrum” protection they must make their defense against UVB and UVA radiation proportional.
“We think this is going to be much easier for the consumer to understand,” Dr. Janet Woodcock, director of the F.D.A.’s drug center, said in an interview. “All they’re going to need to do is pick an SPF number and then make sure that it’s broad spectrum.”
Any product that fails to offer proportional protection or has an SPF of 2 to 14 must include a warning that the product has not been shown to help prevent skin cancer or early skin aging. The new rules will standardize the testing that manufacturers must conduct for UVA protection.
The agency had proposed allowing manufacturers to use SPF numbers no higher than 50, but that remains only a proposal for which the agency will seek further comment. In particular, the government is asking whether there are special groups of people who would somehow benefit from having a product with an SPF of more than 50.
“Right now, we don’t have any data to show that anything above 50 adds any value for anybody,” Dr. Woodcock said.
Dr. Warwick L. Morison, a professor of dermatology at Johns Hopkins University and chairman of the photobiology committee for the Skin Cancer Foundation, said he was disappointed that the F.D.A. failed to ban SPF numbers higher than 50 because such products expose people to more irritating sunscreen ingredients without meaningful added protection.
“It’s pointless,” Dr. Morison said.
More than two million people in the United States are treated each year for the two most common types of skin cancer, basal cell and squamous cell, and more than 68,000 receive a diagnosis of melanoma, the most deadly form of the disease. Sunscreens have not been shown to prevent the first case of basal cell carcinoma, but they delay reoccurrences of basal cell and have been shown to prevent squamous cell and melanoma.
The F.D.A. announced that it was re-examining the safety of the roughly 17 sunscreen agents approved for use in the United States, although it has no information to suggest that they are not safe. Tuesday’s announcement will do nothing to speed the approval of more sunscreen agents. There are roughly 28 such agents approved in Europe and 40 in Japan, and some in the industry complain that the best ingredients have yet to reach American shores.
Some consumer and environmental groups have expressed concern that the ingredients in some sunscreens have been made so microscopic that they could be absorbed through the skin into the body, but Dr. Woodcock said that the F.D.A.’s own tests had found no cause for such concerns.
The agency is also asking for more information about sunscreen sprays to ensure that consumers get adequate quantities from spray bottles and to explore what happens when those products are inhaled. “You could imagine a child getting a sunscreen sprayed on and turning their face into the blast and breathing it in,” Dr. Woodcock said. “It’s a question of safety.”
The new regulations will do nothing to prevent the most common problem with sunscreens lotions, which is that consumers fail to use enough of them. The rules become effective in one year, although manufacturers with less than $25,000 in annual sales will have two years to comply.
Senator Jack Reed, Democrat of Rhode Island, said the new rules were important. Mr. Reed proposed legislation mandating that the F.D.A. finally adopt the sunscreen proposals it floated in 2007.
“The F.D.A. has been sitting on these proposals for many, many years,” Mr. Reed said. “This is a major step, and I’m glad they’ve done it.”