Washington ? It may be the summer of ’09 before beachgoers can count on finding sunscreens to protect against the deeper, penetrating rays linked to wrinkles and cancer.

The Food and Drug Administration on Thursday proposed long-delayed rules covering the ingredients, labeling and testing of sunscreens that boast of protecting against both the sun’s ultraviolet B rays, which cause sunburn, and the ultraviolet A rays that cause tanning but also are associated with more serious and longer-term damage.

The proposed rules keep in place the so-called SPF, or sun protection factor, numerical rating system for UVB protection, while tweaking the testing requirements. The FDA proposes capping the highest SPF value at 50, unless companies can provide results of further testing that would support a higher number, implying better protection against UVB.

The proposal would add a requirement that sunscreen makers assess UVA protection in the laboratory and on people as well if they want to make any claim that their products protect against those rays, whose damage is rarely immediately apparent.

Until recently, most sunscreens sold in the United States have filtered out mostly UVB but not UVA rays – even if they promised broad protection.

The proposed rules would institute a four-star system to rate the UVA protection provided by sunscreens and spell out the protection level as “low,” “medium,” “high,” or “highest.”

“Under today’s proposal, consumers will also now know the level of UVA protection in sunscreens, which will help them make informed decisions about protecting themselves and their children against the harmful effects of the sun,” FDA Commissioner Dr. Andrew von Eschenbach said.

A product’s UVB protection also would be described, alongside its SPF rating. Both the UVA and UVB ratings would receive equal prominence on sunscreen labels.

Companies that choose not to do the UVA testing would have to label their products “No UVA protection,” according to the proposed rules. The FDA assumes three-quarters of the estimated 3,000 sunscreens on the market would undergo such testing.

Schering-Plough Corp., maker of Coppertone, is reviewing the rules, spokeswoman Mary-Fran Faraji said.

FDA announced its intent to draft sunscreen rules in 1978 and published them in 1999. The agency then put them on indefinite hold until it could address issues concerning both UVA and UVB protection.

While the FDA said it would work to expeditiously finalize the rules, it will be at least several years before they take effect.

Under the rules, sunscreen labels also would be updated to further encourage sunbathers to reapply sunscreen as needed. And sunscreens making any claim for water resistance would have to list, in minutes, how long the products block the sun’s rays before they have to be reapplied.

While increased sun exposure has been linked to an increased risk of cancer, the FDA has no data that show sunscreen use reduces that risk. The FDA proposes updating labels to stress that beyond using sunscreen, limiting exposure and wearing protective clothing also can help in guarding against the sun’s effects.