The invasion of the lower respiratory tract by procedures and support measures such as fiberoptic bronchoscopy, endotracheal intubation, and mechanical ventilation generates respiratory aerosols. These aerosols have a potential for the transmission of tuberculosis and other infections. The follow-up of tuberculin skin test status among staff with exposure to this millieu was observed in hope of delineating whether a significant problem does exist. A questionnaire survey of tuberculin skin test status of graduating pulmonary fellows was performed. Graduating Infectious Disease Fellows formed the control group. Training programs situated in the top 25 cities for tuberculosis in 1983 were chosen if the Fellows spent a major proportion of their time in a large receiving/public hospital. The data returned were analyzed if the individual programs had both Pulmonary and Infectious Disease Fellows in training. Fourteen training programs supplied usable data over a 3-yr period. Seven of 62 (11%) of Pulmonary Fellows at risk converted their tuberculin skin test as opposed to one of 42 (2.4%) of Infectious Disease Fellows. This observation raises concern that more fastidious precautions are needed to isolate patients under these conditions of respiratory aerosol generation. The available armamentarium of nonrecirculated fresh air ventilation and ultraviolet light irradiation in addition to simply wearing face masks should be increasingly utilized. Further studies are warranted to substantiate the applicability of these measures to the current situation.