In May 1995, an employee at a garment manufacturing facility, located in a rural community, was diagnosed with cavitary tuberculosis TB. Because the initial contact investigation of family and friends identified a large number of persons with positive tuberculin skin tests TST indicating infection with Mycobacterium tuberculosis, the bacteria that causes TB, the investigation was extended to all coworkers at the plant. In June 1995, the Division of Tuberculosis Elimination DTBE, National Center for HIV, STD, and TB Prevention NCHSTP, Centers for Disease Control and Prevention CDC) was asked to assist the state and local health departments with the investigation. TST screening identified positive skin tests among 75 percent of the work force (174 of 233 workers tested, with documented TST conversions among 30 (17%) workers. In July 1995, the DTBE, NCHSTP, requested assistance from the National Institute for Occupational Safety and Health NIOSH in evaluating the ventilation system at the plant. NIOSH investigators performed an initial evaluation to measure air flow rates and assess air movement within the plant. Because of the unusually high number of positive skin tests found among the employees, a more indepth ventilation assessment was made to document conditions that probably occurred during the period of time the employee with TB was infectious. This involved a tracer gas evaluation to quantify the extent and speed of contaminant dispersion and contaminant removal rate. Sulfur hexafluoride was used as the tracer.
Airborne-particles; Ventilation; Garment-workers; Skin-tests; Bacteria; Pulmonary-disorders; Immune-system; Respiratory-system-disorders; Pulmonary-system-disorders; Infectious-diseases; Lung-disease; Lung-disorders; Disease-transmission; Bacterial-disease; Bacterial-infections; Air-flow; Air-monitoring; Particle-aerodynamics; Medical-screening
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