[Occupational risk of asbestos injuries among workers in the asbestos cement industry]

Dustiness in the asbestos-cement production department of the "Vulkan" plant in Dimitrovgrad was studied. The assay included concentration, dispersion, substance composition, morphology, asbestos content. Two types dustiness were encountered: In the storage and mixing shops the aerosol contained 7 to 78 percent asbestos needles, free from agglomeration; in the moulding and turnery shops the asbestos content rangeal from 2 to 21 percent. Considerable part of the needles were amalgamated by the cement and could be detected only on electron-microscopic observation. The total amount of inhaled asbestos exceeded the amount inhaled at threshold concentration of 0.2 mg pure asbestos aerosol 9 times in the preparatory division and from 2 to 14 times in other shops. In the moulding shop the content was lower than the threshold one. Elevel cases of asbestosis were established: 3 in the preparatory, 4 in the turnery and 3 in other shops. In five cases there were pleural plaques in addition to the parenchymal changes. The minimal length of service to develop asbestosis was 13-14 years at the preparatory division (more free asbestos in the aerosol) and 20-21 years at the turnery shop (less, but agglomerated asbestos). Work with asbestos-cement exposes the workers to a serious risk of development of asbestosis. No principal difference was established in the biologic activity of the two aerosol types; there only is a difference in the degree of their aggressiveness.