In response to a request from a medical facility seeking assistance in documenting occupational ultraviolet (UV) radiation levels emitted by germicidal lamps, NIOSH took measurements of all germicidal lamps at the facility. These lamps were used to disinfect the air in tuberculosis and aerosolized pentamidine clinics. The lamps were low pressure mercury vapor lamps which were primarily a line, rather than broadband source and emitted UV and visible radiation at specific wavelengths. Over 95% of the radiant energy was emitted at a wavelength of 253.7 nanometers. The levels of direct, reflected, and tabletop UV radiation measured exceeded the 8 hour recommended exposure level of 0.1 effective microwatts/square centimeter. No attempt was made to determine how long workers were in a given location since they move quite extensively in performing their duties. UV radiation levels close to the lamp source exceeded the threshold limit values (TLVs) by at least 4000 times, while tabletop exposure levels exceeded the TLV by at least two times. It was recommended that there be a uniform policy for when germicidal lamps are to be replaced, that a training course be provided to lamp replacers to ensure awareness of potential health hazards, that under no conditions should germicidal lamps be used as replacement lamps for conventional fluorescent lamps, that there be a policy on how to label UV lamps, that door interlocks be used as a control measure to minimize health care worker exposure, that the importance of ventilation as a combined control measure not be underestimated, that all highly UV reflecting material be removed from the rooms, that personnel working in these rooms wear UV protective eyewear, that equipment used to measure germicidal UV radiation be maintained, and that it may be necessary to perform ozone measurements when germicidal lamps are used within a restricted area.