Assessment of occupational risk caused by noise exposure in workers at metallurgical plant subunits under modernization
Objective. To evaluate occupational risk caused by exposure to noise in 18 occupational groups in subunits under modernization in an enterprise producing titanium alloys, using methodology of N.F. Izmerov Occupational Medicine Research Institute. Materials and methods. A priori risk evaluation by noise measurements was performed according to criteria of Manuals R 2.2.2006-05, R 2.2.1766-03 and hygienic models, a posteriori one - by analysis of occupational morbidity over 30 years, transitory disablement morbidity and chronic diseases prevalence according to medical examinations data over 5 years. Total of 58758 sick-leave certificates was analyzed. Comparison covered morbidity in individuals exposed to noise (3501 individuals) and non-exposed individuals (9138 ones). Results. Findings are that a risk level by hygienic criteria in the studied occupations was assigned to low to high category (work conditions classes 3.1-3.3), by occupational morbidity criterion - from low to high (index of occupational diseases from 0 to 0.25). Occupational neurosensory deafness was registered in blacksmiths, turners, vertical lathe operators. Noise appeared to be a trigger for diseases of ears, eyes, skin, locomotory system, nervous system, urinary tract, respiratory system, for mental disorders, increased blood pressure, hyperglycemia, leukocytosis, with 1.1-1.7 times reliably increased their risk in general over the production, and up to 3.7 times in certain occupations (p<0.05). Prevalence of the health disorders appeared to increase with growing noise levels. Conclusions. Industrial modernization is associated with decrease of occupational morbidity caused by exposure to noise to single cases and increase of age and length of service at noise conditions to diagnosis. Considerable health improvement was seen in blacksmiths, after hammer equipment was changed to the press one, in lathe operators - after lathe changed to processing centers with numerical control.