The German Chemicals Act of 1980 which came into force on January 1, 1982 aims to protect man and the environment from the unwanted effects of chemicals. As is true for all quality control legislation for chemical products, the scientific goal is to simulate under controlled conditions agent-target interactions as are likely to occur and to estimate the probability of agents reaching the target: the hazard of a chemical is a function of exposure and effect considerations. Beyond attempting to control chemical products, it may soon become necessary to consider the totality of all substances entering the environment as a consequence of technological activities: raw material extraction, production, transport, storage, and waste disposal. The paper aims at identifying important areas of research where it is felt that more systematic knowledge could help to render administrative decision-making processes more transparent, more cost effective, and bring them better in line with the legal mandate of protecting the environment from dangerous chemicals. While the paper focuses on problems surrounding the multitude of "existing chemicals," many an item discussed is significant also for the preventive protection from dangerous "new chemicals."