Dust conditions in brick plants of Ontario.

Investigations have been carried out into the dust conditions in brick plants of Ontario. Shales and clays used in manufacturing bricks have been analyzed and found to contain free silica as high as 28%. However, to date, no silicotics have been found in the brick industry. The high-volume sampler, midget impinger, and Hexhlet size-selective sampler were used to evaluate the total and respirable dust concentrations in the air. An attempt was made to correlate the dust conditions and occupational histories of workers with the medical findings. This paper emphasizes that all aspects of production and all operations in brick plants must be carefully evaluated in order to design an adequate dust control system. Examples are used to illustrate the difficulties that can occur and how they can be eliminated.