More than 100 ingredients suspected of causing cancer and birth defects are available for use in cosmetics, virtually free of federal regulation, congressional investigators have found.

A General Accounting Office survey of cosmetics, to be delivered to a House subcommittee today, found that millions of consumers may be exposed to "significant hazards" from the ingredients of beauty product.

The GAO report is critical of the Food and Drug Administration for alleged laxity of enforcement of existing federal cosmetics law.

But the GAO also determined that the law does not provide adequate powers for FDA to protect consumers from potential health hazards.

GAO's investigation will be discussed in detail today by the interstate and Foreign Commerce oversignt subcommittee, headed by Rep. John E. Moss (D-Calif.)

The subcommittee also will hear from FDA Commissioner Donald Kennedy and according to Moss aides, discuss legislation to ban the use of cancer-causing coal tar dyes in hair-coloring products.

he GAO report did not specify which of the potentially harmful ingredients are being used in cosmetics, nor did it name cosmetics that contain them.

But the investigators found that dozens of suspect agents are on the market, out of the reach of federal control, for use in cosmetics. They included:

About 100 ingredients listed as suspected carcinogens by the National Institute of Occupational Safety and Health's Registry of Toxic Effects of Chemical Substances.

Twenty-four ingredients listed in the registry as suspected of causing birth defects.

Twenty more than may cause adverse effects on the nervous system, including headaches, drowsiness and convulsions.

GAO noted that products listed on the NIOSH registry had been tested on laboratory animals and that their correlation to cosmetics exposure has not been evaluated.

But, the report continued, the Food, Drug and Cosmetic Act - which partially governs cosmetics content and labeling - does not give the FDA sufficient authority to assure that the product are harmless.

A specific exemption in the act bars the FDA from banning or restricting the use of coal tar dyes in hair-coloring products used by an estimated 33 million people.

Increasing evidence has shown that some colors used in coal tar hair dyes are capable of causing cancer in consumers, and the FDA has proposed warning labels for such products.

The Cosmetic, Toiletry and Fragrance Association (CTFEA) an industry group, has opposed the FDA move. Association officials have maintained that no major hair dye manufacturer has used benzidine-derived colors - one of the major suspected carninogens - in their products since 1973.

GAO investigators, however, recently purchased eight temporary rinses containing one or more of the benzidine-derived colors at durgstores in Rockville. The manufactorer, not named by GAO, is a CTFA member.

The GAO report that will be discussed today calls for a repeal of the exemptions for coal tar hair dyes.

GAO said that while the FDA does not have certain regulatory powers that would be helpful - such as a requirement that manufacturers test their cosmetics for safety - it could do a better job with the powers it has.

The investigators found that FDA has not inspected most plants or sampled products, as it is empowered to do. It has not established manufacturing standards, nor has it forcefully followed up with penalties after discovering violations of the law, GAO said.

GAO said the FDA has been lax in requiring warning labels on suspect products, and noted that some ingredients banned in other countries are available freely here without challenge by the FDA.

The agency also was critized for failing to established regulations limiting color additives that are not safe for use in cosmetics and for not establishing tests for safety evaluation of cosmetics.