Evolution of working conditions at dust-hazardous enterprises in Western Siberia: 50-year trends

To identify the main 50-year trends in evolution of working conditions at dust-hazardous enterprises in Western Siberia, the sanitary and hygienic characteristics of working conditions of staff with suspected occupational diseases, issued by the regional offices of The Federal Service for Surveillance on Consumer Rights Protection and Wellbeing (Rospotrebnadzor) to 447 patients with pneumoconiosis diagnosed from 1960 to 2010 were analyzed, as well as a retrospective analysis of the dynamics of changes in working conditions according to the research reports of the Novosibirsk Research Institute of Hygiene for the period 1930–1960 was made. In the 1950s the most harmful silicotic working conditions were observed in sandblasters exposed to newly formed modifications of silica in concentrations of 20–340 mg/m3. Since the 1970s, industrial enterprises in Novosibirsk and the Novosibirsk Region have experienced a significant decrease in dustiness levels (by tens and hundreds of times) — up to 4–40 mg/m3. In the last decade of the XX century, at a number of enterprises, the volume of production and the overall working time, during which there was direct contact with industrial aerosols, decreased, and the proportion of 3.4 class working conditions over the last decade decreased by 2.49 times (p ≤ 0.001). There was a change in working conditions for the production of refractory materials and ceramic products. Electric welders with all types of manual welding were exposed to a combined effect of hazardous occupational factors without significant changes in the levels of industrial aerosols in the workplace.