The NIOSH National Occupational Health Survey of Mining (NOHSM) Query System was discussed. The system was based on data obtained in a NIOSH survey of 491 mines in 70 United States (US) mining industries between May 1984 and August 1989. The purpose of the survey, as requested by the Mine Safety and Health Administration (MHSA), was to identify and characterize health related agents to which US miners were potentially exposed. The survey consisted of a questionnaire survey of mine managers, an inventory that described all substances found on the mine site and the annual usage of each agent, and worksite surveys. The worksite data were collected for seven categories of potential exposure: generic chemicals, trade name products, physical agents, musculoskeletal overload conditions, welding processes, grinding metals, and bulk settled dust. A total of 2,451 generic chemicals and 49,799 trade name products were entered into the NOHSM Query System. Some of the achievements of the system to date included publication of the results of analyses of the quartz (14808607) content of bulk dust samples, distribution of inventory reports to all 491 mining sites surveyed, and the generation of special reports for MHSA, the American Conference of Governmental Industrial Hygienists and NIOSH. Examples of the use of the NOHSM Query system were provided. Examples of user requests and queries for information were presented. The National Occupational Health Information System (NOHIS) was discussed. NOHIS is a enhancement project in which NIOSH is attempting to integrate the NOHSM Query system, trade name ingredients, MSHA inspection data, OSHA inspection data, NIOSH survey data, and Bureau of Mines data to form one unified database.