This testimony concerned the efforts of NIOSH to protect the health of workers involved with industrial applications of recombinant DNA techniques. The rapid growth of recombinant DNA technology in pharmaceutical, chemical, agricultural, energy and food processing facets of the economy indicated the need for careful evaluation of health risks to workers in these areas. A recent National Institutes of Health workshop addressed the question of risks related to Escherichia-coli-K-12 production of insulin and human growth hormone. Those possibly exposed to recombinant DNA will include not only scientists, but also technicians, maintenance and custodial personnel. As there often has been a long latency period with occupational diseases, there is no assurance that just because no problems have been identified among the workers as yet that there are no problems there. Retrospective research was underway. NIOSH was also conducting on site studies of commercial facilities as they begin pilot operations and production. NIOSH also planned to evaluate the submission from private companies on large scale research or production made to the Recombinant DNA Advisory Committee. All these undertakings were being made in close cooperation with the Center for Disease Control and the Occupational Safety and Health Administration. Recommendations which were made in 1977 to the Subcommittee on Health and the Environment were restated.