The German Chemicals Act of 1980 (Chemikaliengesetz - ChemG) stipulates that certain existing chemicals must be reported to the competent authority, if they exhibit properties which indicate they may be hazardous, either alone or in combination with other chemicals. In summer, 1982, an Advisory Committee on Existing Chemicals of Environmental Relevance (BUA), consisting of representatives from science, chemical industry and governmental authorities, was established at the Society of German Chemists (GDCh). Its purpose was to seek appropriate solutions for dealing with chemicals which are relevant to health and the environment through the adoption of voluntary measures. It is the responsibility of this committee to select and examine existing chemicals for environmental or health purposes. In doing so, exclusively scientific criteria are to be applied. Therefore, priority setting had to be developed, and in the first instance only priority chemicals were investigated in detail by reports. For a first priority setting chemicals were compiled from various priority lists and 135 substances selected for detailed reports. In a second priority setting substances with high production volume were considered from a list of the German chemical industry (VCI), comprising approximately 4500 chemicals with production volumes larger that 10 tonnes per year. The detailed BUA reports are considering the published literature as well as data from industry. If data for the evaluation of the chemicals are missing, further investigations are recommended and the results of these recommendations will be published in later ammendments to the reports. The reports will be the basis for administrative measures if the data indicate hazards for the environment and health.