After 30 years in bureaucratic limbo, the FDA has approved new rules, published today, intended to alleviate consumer confusion about sunscreen effectiveness.

In order to claim they protect against skin cancer, sunscreen manufacturers will have to prove they filter out bothultraviolet B rays and ultraviolet A rays.  Additionally, any sunscreen with an SPF of 15 or less will have to bear the following warning:  ”This product has been shown only to help prevent sunburn, not skin cancer or early skin aging.”

The key takeaway for consumers: Look for a sun protection factor, or SPF, of 15 and above that also says “broad spectrum.” That’s the new buzzword from the Food and Drug Administration to describe a product that does an acceptable job blocking both types of damaging rays.

The new regulations require that sunscreens be tested for the ability to block the more dangerous ultraviolet A rays, which can penetrate glass and pose the greatest risk of skin cancer and premature aging. Currently, the FDA requires testing for only ultraviolet B rays that cause sunburn. The current SPF labeling system only deals with ultraviolet B rays.

Under the new rules:

• The FDA will prohibit sunscreen marketing claims like “waterproof” and “sweatproof,” which the agency said “are exaggerations of performance.”

• The FDA also proposes capping the highest SPF value at 50, unless companies can provide results of further testing that support a higher number.

• FDA says manufacturers must phase out a four-star system currently used by some companies to rate UVA protection.

After reviewing more than 3,000 public comments, the agency concluded the star system was too confusing for consumers. Instead, protection against UVA should be proportional to protection against UVB, which is already measured using SPF.