Assessing and predicting individual occupational risk and determining its exact categories using probabilistic methods

Existing approaches to occupational risk assessment more often involve evaluating its group levels and individual risks are assessed less frequently. These approaches provide deterministic risk assessment which doesn’t take into account uncertainty in risk categorizing when its values are close to boundaries between adjoining risks categories. It substantiates the necessity to assess occupational risk levels using probabilistic methods. Our research object was occupational risk and the basic subject was distribution of individual occupational risk levels among workers. Our test group was made up of oil and gas extraction operators exposed to noise equal to 80-85 dBA at their workplaces (173 people). Our control group included oil and gas extraction operators and engineering and technical personnel occupationally exposed to noise equal to 60-77.8 dBA (259 people). We performed a priori assessment of occupational health risks; accomplished epidemiologic analysis of a cause-effect relation between health disorders and work; calculated group occupational health risks; calculated and predicted individual occupational risk using mathematical modeling of dependence between probable negative responses and working conditions, age, and period of employment; determined risk categories more precisely using fuzzy sets by calculating the membership function. As a result, we established that proven individual risk levels were distributed unevenly (1.06·10-4-1.47·10-2) as per categories within a group characterized with a suspected average risk level. A category of proven individual risk levels was determined more precisely using fuzzy sets; after that distribution of probability of their membership was evaluated to detect that at the moment of the research a share of workers with their proven individual occupational risks falling into lower risk categories (p > 0.5) amounted to 89.6 %. We attempted to predict risks for the whole employment period given that working conditions remained the same and no prevention activities were provided. Our prediction revealed that individual occupational risks would remain unacceptable for all workers in the test group and would amount to 2.53·10-2-3.51·10-2; a risk category was also expected to become higher. Individual occupational risk would be categorized as average for most workers and as high for 23 % of them (p function show_eabstract() { $('#eabstract1').hide(); $('#eabstract2').show(); $('#eabstract_expand').hide(); }