Occupational Noise Exposure

In the Occupational Safety and Health Act of 1970, Congress declared that its purpose was to assure, so far as possible, safe and healthful working conditions for every working man and woman and to preserve our human resources. In this Act, the National Institute for Occupational Safety and Health (NIOSH) is charged with recommending occupational safety and health standards and describing exposure concentrations that are safe for various periods of employment-including but not limited to concentrations at which no worker will suffer diminished health, functional capacity, or life expectancy as a result of his or her work experience. By means of criteria documents, NIOSH communicates these recommended standards to regulatory agencies (including the Occupational Safety and Health Administration [OSHA]) and to others in the occupational safety and health community. Criteria documents provide the scientific basis for new occupational safety and health standards. These documents generally contain a critical review of the scientific and technical information available on the prevalence of hazards, the existence of safety and health risks, and the adequacy of control methods. In addition to transmitting these documents to the Department of Labor, NIOSH also distributes them to health professionals in academic institutions, industry, organized labor, public interest groups, and other government agencies. In 1972, NIOSH published Criteria for a Recommended Standard: Occupational Exposure to Noise, which provided the basis for a recommended standard to reduce the risk of developing permanent hearing loss as a result of occupational noise exposure [NIOSH 1972]. NIOSH has now evaluated the latest scientific information and has revised some of its previous recommendations. The 1998 recommendations go beyond attempting to conserve hearing by focusing on preventing occupational noise-induced hearing loss (NIHL). This criteria document reevaluates and reaffirms the recommended exposure limit (REL) for occupational noise exposure established by the National Institute for Occupational Safety and Health (NIOSH) in 1972. The REL is 85 decibels, A-weighted, as an 8-hr time-weighted average (85 dBA as an 8-hr TWA). Exposures at or above this level are hazardous. By incorporating the 4000-Hz audiometric frequency into the definition of hearing impairment in the risk assessment, NIOSH has found an 8% excess risk of developing occupational noise-induced hearing loss (NIHL) during a 40-year lifetime exposure at the 85-dBA REL. NIOSH has also found that scientific evidence supports the use of a 3-dB exchange rate for the calculation of TWA exposures to noise. The recommendations in this document go beyond attempts to conserve hearing by focusing on prevention of occupational NIHL. For workers whose noise exposures equal or exceed 85 dBA, NIOSH recommends a hearing loss prevention program (HLPP) that includes exposure assessment, engineering and administrative controls, proper use of hearing protectors, audiometric evaluation, education and motivation, recordkeeping, and program audits and evaluations. Audiometric evaluation is an important component of an HLPP. To provide early identification of workers with increasing hearing loss, NIOSH has revised the criterion for significant threshold shift to an increase of 15 dB in the hearing threshold level (HTL) at 500, 1000, 2000, 3000, 4000, or 6000 Hz in either ear, as determined by two consecutive tests. To permit timely intervention and prevent further hearing losses in workers whose HTLs have increased because of occupational noise exposure, NIOSH no longer recommends age correction on individual audiograms.

This anthology provides readers of scientific literature on socioeconomic factors and working conditions with the newest knowledge in this field. Since our world is subjected to constant change in accelerating speed, scientific reviews and updates are needed. Fortunately, research methodology in epidemiology, physiology, psychology and sociology is also developing rapidly and therefore the scientific community can provide politicians and policy makers with increasingly sophisticated and exact descriptions of societal factors in relation to work. The anthology starts in the macro level sphere – with international perspectives and reviews related to working conditions in relation to political change (the fall of the Soviet Union) gender, age, precarious employment, national economy and retirement. Two chapters relate to national policies and activities in international organizations. The second part of the book relates to the meso level sphere – with reviews on social patterns in distributions of psychosocial and physical risks at work in general as well as reviews on noise, shift work, under/overemployment, occupational physical activity, job intensity (which may be a particularly important problem in low income countries), digitization in modern work, climate change, childhood determinants of occupational health in adult years and theoretical models currently used in occupational epidemiology - demand/control, effort/reward, organizational justice, psychosocial safety climate, conflicts, bullying/harassment. This part of the book ends with two chapters on interventions (one chapter on the use of cultural interventions and one on interventions and their evaluation in general) and two chapters on financial aspects of poor/good work environments and evaluations of interventions. In the third part of the book the micro level is addressed. Here mechanisms translating working conditions into physiology are discussed. This starts in general theory relating basic theories regarding energy storage and release to psychosocial theory (extension of demand control theory). It also includes regeneration physiology, autonomic nervous system function, immunology and adverse behaviour. Sections in the Handbook: Macro-level determinants of occupational health: Akizumi Tsutsumi, Meso-level determinants of occupational health: Morten Wahrendorf and Jian Li, Micro-level determinants of occupational health: Bradley J. Wright

Every day, millions of employees in Europe are exposed to loud noise at work. This is the case not just in heavy industries but also in a wide range of sectors including agriculture and service industries. Noise at work has been designated at the theme for the European Week for Safety and Health 2005, and this report examines noise control measures including relevant European Directives and supporting international standards. It looks at interventions in the workplace to examine and prevent the risks arising from noise exposure in terms of personal, social and economic cost of ill health and accidents.