An industrial hygiene and respiratory disease prevalence study was performed at 37 cotton gins (SIC-2211) in the southern United States. Results were compared with those from comparison workers in nonindustrial occupations matched for sex, race, age, height, weight, smoking status, and region. Ambient respirable cotton dust concentrations were measured using vertical elutriators, and particle size distribution was characterized. Standard pulmonary function testing and respiratory questionnaires were used to assess lung function, work history, smoking history, and respiratory symptoms. Geometric mean dust concentrations ranged from 0.13 milligrams per cubic meter (mg/m3) in the yard to 0.37mg/m3 at the gin stand. Air movement and machinery layout had a significant effect on dust concentrations. The mass median diameter of particles ranged from 2.7 to 8.5 microns with a mean of 5.30 microns. Cotton gin workers tended to experience more dyspnea and bronchitis than comparisons, but this difference was significant only for bronchitis among gin workers who had never smoked. There was no excess prevalence of byssinosis in gin workers compared to nonindustrial workers. Nonsmoking gin workers had significantly more respiratory disorders arising from exposure to textile vegetable dusts. There was an increasing prevalence of bronchitis as dust concentrations increased in gin workers who never smoked. Increases were seen in respiratory disorders as textile vegetable dust concentrations and years of exposure increased. The author concludes that cotton dust exposure causes increases in bronchitis and respiratory disorders and decreases in lung function. It is recommended that 0.500mg/m3 geometric mean be set as a standard for the cotton ginning industry. Suggestions are made for controlling employee cotton dust exposure and implementing a medical surveillance program in the industry.
Appalachian Laboratory for Occupational Safety and Health, NIOSH, Morgantown, West Virginia, NTIS PB83-232-165, 77 pages, 28 references