NIOSH recommendations for 102 hazardous substances and 8 hazardous processes or occupational situations are reviewed. A summary of each of the major recommendations found in the Criteria Documents and Special Hazard Reviews published by NIOSH is provided for each potential hazard. To formulate the recommendations made in Criteria Documents, NIOSH evaluates all known and available medical, biological, engineering, chemical, trade, and other information relevant to the potential hazard. The Special Hazard Reviews assess, from the standpoint of health, specific problems associated with a given agent or hazard, such as its potential for carcinogenic, mutagenic, or teratogenic effects, and recommends appropriate methods for control and surveillance. OSHA regulations as of 1982 for the same substances and situations are presented. Significant health effects that are considered by NIOSH in developing the recommendations are listed. Hazardous processes and situations considered include coal liquefaction and gasification, working in confined spaces, emergency egress from elevated work stations, hot environments, logging, noisy environments, and rendering processes.