Health hazard evaluation determination report, MHETA 81-112, NYCO, Willsboro, New York.
In 1976, NIOSH performed a health hazard evaluation at a wollastonite mine and mill in Willsboro, New York. A second NIOSH medical-epidemiological evaluation was conducted among 108 current and former workers in January 1982, and the results of that study are reported herein. The medical evaluation consisted of chest radiography, pulmonary function tests, and administration of a respiratory symptom and occupational questionnaire. Chest x-rays were interpreted by three independent, certified pneumoconiosis readers and pulmonary function tests conformed to criteria recommended for spirometry by the American Thoracic Society. On the basis of total dust data collected between 1976 and 1981 by the Mine Safety and Health Administration (MSHA) , company, and NIOSH, an exposure index was calculated for each worker. For interpretation of lung function a control group of 86 workers employed by a local General Electric plant was used. Medical testing showed wollastonite workers to have lower values of FEVl/FVC and peak flow rate when compared with the control group. A dose-response relationship was found between decreasing values of FEVl, peak-flow, FEVl/FVC and cumulative long-term exposure to wollastonite containing dust. Three cases of simple pneumoconiosis (category 1/0 or 1/1 small rounded opacities) were found among the 108 wollastonite workers examined. No new cases of pneumoconiosis were found in 1982. Chest x-rays were not obtained for the comparison group of workers. Fifty-seven wollastonite workers were examined by NIOSH both in 1976 and 1982. Analysis of data on these 57 men revealed that workers with higher cumulative exposure to wollastonite had greater peak flow declines than workers with lower cumulative exposure. The medical data suggest that long term cumulative exposure to wollastonite dust may impair ventilatory capacity as reflected by observed decrements in peak flow rate and FEV1/FVC ratio. This effect appears to involve the larger airways. While simple pneumoconiosis was observed in three individuals, no comparison group chest films were available to assess the significance of this observation. Further prospective study of this population is-recommended.