Integrated in this micro-thesaurus of indexing terms are keywords from the Department of Defense thesaurus, the Energy Research and Development Administration thesaurus, the National Aeronautics and Space Administration thesaurus, and the thesaurus used by the National Technical Information Service (NTIS). Included are controlled free language terms which may be useful in searching the NTIS data base. The terms are listed hierarchically with main entries followed by narrower terms, broader terms, related terms, and scope notes. The parent thesaurus source of each term is identified. The micro-thesaurus is divided into two sections. The first section contains more than 1800 terms that express environmental concepts relating to water, air, noise, and radiation pollution, disposal of solid waste, and environmental health. The second section lists more that 550 chemicals that are important to environmental studies. (BB)