Dust, Radiation and Diesel Exhaust Exposures in Ontario Uranium Mines and Mills

Aim: The objective of this paper was to summarize a comprehensive survey of airborne dust, radiation, and diesel exhaust in two Ontario uranium mines which was conducted by the Occupational Health Protection Branch of Ontario Ministry of Health in 1974. Materials and Methods: About 1000 dust samples of various types were collected from the mine and mill areas under normal routine working conditions. Dust sampling was conducted using various sampling devices including midget impingers, konimeters, and both area and personal respirable dust samplers. About 400 measurements of radon daughter concentrations were made, usually in the same area where dust samples were taken. Diesel exhaust gases, carbon monoxide, formaldehyde, and oxides of nitrogen, were measured using Drager colorimetric tubes, as an index of diesel exposure. Unburnt carbon from diesel exhaust was determined from some of the dust samples. Results: The results show that dust exposure, including crystalline silica (α‑quartz), was generally higher than the recommended exposure limits of the time. Radon exposure was also in excess of the exposure limits of the time in some work areas. Diesel exhaust gases were mostly below the threshold limit value of the time. Conclusions: The data set described in this paper would be useful in future epidemiological or health studies of the uranium miners group for establishing the work‑relatedness for diseases such as lung cancer from radon exposure and silica, respiratory diseases such as silicosis and chronic obstructive pulmonary disease, and autoimmune diseases. It would also be useful in estimating exposure of individual miners for the assessment of compensation claims.