The Cosmetic Ingredient Review (CIR) program was established in 1976 by the Cosmetics, Toiletry, and Fragrance Association, with the support of the Food and Drug Administration (FDA) and the Consumer Federation of America (CFA). CIR performs independent, expert reviews to determine if ingredients used in cosmetics are safe. CIR staff prepares summaries of available data and the CIR Expert Panel reviews the data in open, public meetings. If more data are needed, requests are made. Unpublished studies may be provided, but become public and available for review once summarized in CIR safety assessments. Tentative conclusions are supported with a rationale and public comment is sought. Taking any input into consideration, a final safety assessment monograph is issued. These monographs are submitted for publication in the peer-reviewed International Journal of Toxicology . To date, 1194 individual cosmetic ingredients have been addressed. Of these, 683 were found to be safe in cosmetics in the present practices of use and concentration. With qualifications, another 388 have been found safe for use in cosmetics; specific qualifications for each are given. Nine ingredients have been deemed unsafe for use in cosmetics and the safety issue has been described. The available data were found insufficient to support the safety of 114 ingredients; the needed data are listed. Hair dyes represent an important product category reviewed by CIR. In considering hair dyes, the CIR Expert Panel reviews experimental and clinical data specific to the particular chemical structure of each hair dye and reviews epidemiologic studies that address hair dye use that are less specific. Recently the CIR Expert Panel concluded that the available epidemiologic studies are insufficient to conclude there is a causal relationship between hair dye use and cancer and other end points. It is inevitable that new information will become available concerning ingredients for which safety assessments were completed in the early days of the program. To consider new data, the CIR Expert Panel has instituted a re-review program. Sodium lauryl sulfate (SLS), formaldehyde, and parabens are discussed as examples. Safety assessments currently underway are listed, along with high-priority ingredients from which new work will be chosen. Although supported by the cosmetics industry, the CIR program has remained independent in its decision making, based on its open, public process; the integrity of the expert panel members; the participation of the FDA and the CFA; and the cooperation of the cosmetics industry.