WASHINGTON (AP) _ The cosmetics industry is rejecting a consumer group's claim that some of the very products that people use to protect themselves from the sun contain an ingredient that may promote skin cancer.

The Cosmetic, Toiletry and Fragrance Association said the ingredient in question, urocanic acid, is used in very few sun screens and cosmetics, and has not been shown to adversely affect human health.

''It's very important that people not be frightened about using sun screen,'' said Eileen Malbin, a spokeswoman for the association.

The Consumer Federation of America on Thursday said more than a dozen cosmetic products have been sold containing urocanic acid, which it said has the potential in sunlight to promote the growth of tumors by suppressing the immune system.

''We believe it is important for consumers to discontinue use immediately of sun screens and skin-care lotions containing urocanic acid,'' said Mary Ellen Fise, the group's product safety director.

The federation, joined by two research scientists at The George Washington University Medical Center, petitioned the Food and Drug Administration to ban sales of cosmetics that contain urocanic acid.

''Based on our original research, now supported by other laboratories, it is our scientific opinion that any benefit gained by inclusion of urocanic acid in cosmetics is far outweighed by the potential risks,'' said one of the scientists, Dr. Edward DeFabo.

But the cosmetics trade group said that while studies have indicated urocanic acid can cause immunosuppressive activity in animals, ''preliminary human data indicates there is no cause for concern.''

The independent Cosmetic Ingredient Review Expert Panel has asked the cosmetics industry to conduct studies on the safety of urocanic acid, the trade group said. It added that the cosmetic panel has determined that existing information does not justify a finding that urocanic acid is unsafe.

The consumer federation said urocanic acid was banned recently for cosmetic use in Australia and products containing it were removed from shelves in Singapore, apparently voluntarily by cosmetic manufacturers.

The consumer group said voluntary reports to FDA by cosmetic manufacturers in 1989 showed that urocanic acid was being used in 15 products, including 10 sun screens, three body lotions, one makeup base and one makeup foundation.

FDA spokeswoman Bonnie Aikman said the agency is reviewing the group's petition. She said four of the 15 products no longer are on the market.

The 15 products were not identified by the FDA, but the consumer federation said it recently had located in stores eight cosmetic items that contained urocanic acid. They were: Estee Lauder Sun Face Block for Sensitive Skin, Estee Lauder Overnight Pre-Tan Accelerator, Estee Lauder Waterworld Sunscreen, Estee Lauder Oil-Free Tanning Formula, Shiseido Pre-Makeup Cream Base, Shiseido Facial Moisturizing Lotion, Clinique Self-Tanning Formula and Germaine Monteil Pre-Tan.

Rebecca McGreevy, a spokeswoman for Estee Lauder, said the Estee Lauder products were reformulated last September and no longer contain urocanic acid. Clinique spokeswoman Susan Oberstein said the same was true for the Clinique product. James Conroy, a spokesman for Revlon, which owns Germaine Monteil, said the listed product had not been produced for two years and had contained a urocanic acid derivative that was not relevant to the consumer group's concerns. Shiseido said its Pre-Makeup Cream no longer has urocanic acid.

The cosmetics trade group said urocanic acid would be listed on the label of any cosmetic product in which it is included. Fise said it may be difficult for consumers to determine whether cosmetics they have already purchased contain urocanic acid because ingredient labels usually appear on outer packaging that may have been discarded.