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Tuberculosis in the Workplace
most workers might not pass a fit test with the currently available models of the widely used N95 respirator. This suggests that more attention should perhaps be paid to mask performance at the manufacturing and premarketing stage.
A determination that qualitative fit testing is ineffective and that quantitative fit testing is required could add substantial costs to a respiratory protection program, especially one that included annual testing for large numbers of workers. The findings by Coffey and colleagues raise a further serious concern that with quantitative fit testing, most workers might not pass a fit test with the widely used N95 respirator.
The committee found no epidemiologic studies that have evaluated whether qualitative or quantitative fit testing (either initial or annual) for N95 or other respirators used for tuberculosis control improves respirator fit in normal practice as workers treat, transport, guard, or otherwise have contact with people who have known or suspected tuberculosis. Given the relatively small numbers of workers with skin test conversions, it is unlikely that field studies would be sensitive enough to demonstrate whether initial or annual fit testing reduced worker’s occupational risk of acquiring tuberculosis infection or active tuberculosis. The committee located no modeling studies that focused specifically on the potential health effects of fit testing.
One small, single-site study has suggested that education about proper fit may be as effective as physical fit testing (Hannum et al., 1996). In that study, a hospital recruited workers to participate in one of three respirator training programs. Researchers then tested the workers on their ability to correctly adjust their respirator’s fit and seal. They concluded that training was important but that it did not matter much whether the training included direct fit testing or a classroom demonstration of how workers should fit check their respirator before each use. The devices used in the study were high-efficiency particulate air (HEPA) respirators, which differ from the now widely used N95 respirators. Thus, this study is not directly relevant to N95 respirators.
Flexibility of Respiratory Protection Requirements Perhaps paradoxically the committee’s most daunting challenge was to assess whether the 1997 proposed OSHA rule allowed employers reasonable flexibility to match respiratory protections to the level of risk. Although the group agreed that respiratory protection is the least important of the hierarchy of tuberculosis controls, it also agreed that respirators and respiratory protection programs have a role to play when an occupational risk of tuberculosis exists.
As described in Chapter 6, modeling studies suggest that the benefits of respiratory protection are directly proportional to the presence of risk. In facilities that admit only the occasional individual with tuberculosis or