Noise at a workplace: permissible noise levels, risk assessment and hearing loss prediction

Noise is a major occupational risk factor that causes hearing loss, one of the most widely spread occupational diseases. Recently some new standards that regulate noise at workplace have been fixed and risk assessment in the sphere has become necessary, so now it is vital to get better insights into the matter. The purpose of the work was to analyze peculiarities of occupational risk assessment performed for workplaces where there was a lot of in-plant noise taking into account international documents and national practices. Analysis of legal grounds for occupational risk assessment revealed that the most important issue in it was to determine probability of a damage to a worker's health. Only an employer can manage risks as it is him who has created them; hygienists, as per ILO Convention No. 161, are responsible for informing and giving recommendations to workers and employers on prevention measures. Methodology of occupational risk assessment that is applied in occupational medicine is a scientific foundation in the process. Analysis of risk assessment principles revealed it was necessary to determine tolerable risk, and not an acceptable one. Necessary and sufficient condition of evidential risk assessment is a hazardous factor existing at a workplace that exceeds maximum allowable concentrations or permissible exposure levels and prediction of a disease caused by this factor. According to the Guide P 2.2.1766-03, occupational risk is considered to be proven when there are data on workers' health; but as per data of working conditions assessment and criteria set forth by the Guide P 2.2.2006-5 it is thought to be only suspected. So, data obtained via specific assessment of working conditions are not sufficient to assess actual occupational risks. In 2010 the ILO issued an important document on emerging risks and new prevention forms. EU Strategic Framework on Health and Safety at Work 2014-2020 focuses on new and emerging risks as well as on probable new occupational diseases and work-related diseases. Recently some scientific works have been published that dwell on predicting risks caused by new technologies, physical, biological, psychosocial, and chemical factors. Directive 2003/10/EC issued in the EU differentiates noise standards as per urgency of measures taken, and these standards allow for means of individual protection applied to protect hearing organs; all the standards are also supplemented with practical guides. The Noise Regulations issued in Great Britain in 2005 give the following definition for risk assessment: it is determination of exposure to noise, account of risks borne by exposed groups of workers, assessment of combined effects produced by noise and ototoxic substances, as well as by noise and vibration. The author provides data that validate effects of occupational exposure to noise (the WHO, 2004) and notes that though an increase in permissible noise level from 80 to 85 dB is considered to be acceptable, the idea is rather controversial. The State Standard P ISO 1999-2017 on prediction of hearing loss caused by noise is well in line with the opinion expressed by the WHO experts that exposure to noise can cause disability. Conclusion. There is a logical chain for occupational risk assess-ment in case of noise: exposure assessment - determination of working conditions category (hazard degree) - calculation of hearing loss probability as per State Standard P ISO 1999-2017 - prevention measures - necessity to work out specific programs aimed at hearing preservation recommended by the ILO. These programs can reduce risk and extra-aural noise effects; they should be drawn up as Sanitary rules or a State Standard and help to preserve health and provide safe and productive work