This testimony concerns the activities of NIOSH in relation to the establishment of certain guidelines for safety in the diving profession. A report on recommended diving standards was delivered to OSHA by NIOSH on August 18, 1976 to aid OSHA in the development of a final standard. NIOSH was beginning a major epidemiologic study which will be concerned with an assessment of the mortality experience of divers, a cross sectional morbidity study to help determine the current health status of divers, and an evaluation of the need for improved surveillance of injuries and illnesses resulting from, or correlated with commercial diving. The comments in this testimony also relate to the evaluation and improvement of diving tables, decompression sickness and resultant tissue damage, the early detection of decompression sickness, and the listing of absolute physical disqualifiers. A scheme to lower the current incidence of bends was adopted by OSHA. The statistical approach taken by OSHA was supported by NIOSH. It is recommended that OSHA institute a reporting system for diving incidents. NIOSH finds the use of disqualifiers to be justified in the case of professional diving due to the extremely arduous conditions normally found, and even more stressful emergency conditions.