A tracer gas evaluation at a garment manufacturing facility with extensive transmission of tuberculosis.
Seitz-TA; Mortimer-V; Martinez-K
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 1998 May; :34
NIOSH assistance was requested in evaluating ventilation conditions at a garment manufacturing facility after an employee was diagnosed with active cavitary tuberculosis (TB). A contact investigation by local health departments and the Centers for Disease Control and Prevention (CDC) identified an unusually high number of positive tuberculin skin tests among co-workers (174 of 233 workers tested). NIOSH investigators conducted a tracer gas evaluation using sulfur hexafluoride to quantify the extent of containment dispersion and containment removal rate. The tracer gas evaluation showed that the plant had excellent air mixing and a low air change rate, typically less than 0.4 air changes per hour (ACH). When the tracer gas was released in the middle of the plant, it was detected at the furthest points in the production area (approximately 100 feet away) within 11 minutes. The tracer gas was also detected in the adjacent engineering and main office areas, the cafeteria, and the conference room. The environmental evaluation determination that ventilation conditions were favorable for TB transmission based on a low air change rate and excellent air mixing within the plant. Thus, TB bacteria would have spread quickly and uniformly throughout the plant, and remained suspended for hours before being removed from the air. It is impossible to predict, however, to what extent ventilation played a role in TB transmission. Other factors that may have influenced TB transmission in this setting include prolonged infectiousness of the individual and virulence of the organism. The latter factor was subsequently evaluated by researchers at CDC and is believed to have played a major role in the extensive amount of TB transmission in this workplace as well as in the community.
Airborne-particles; Ventilation; Garment-workers; Skin-tests; Bacteria; Pulmonary-disorders; Immune-system; Respiratory-system-disorders; Pulmonary-system-disorders; Infectious-diseases; Lung-disease; Lung-disorders; Air-flow; Air-monitoring; Disease-transmission; Industrial-factory-workers; Disease-incidence; Bacterial-disease; Bacterial-infections; Particle-aerodynamics
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia