Negative health outcomes arising from exposure to noise at work
Exposure to workplace noise can cause hearing problems, such as hearing loss and tinnitus. However, there is evidence to suggest that noise exposure is also related to non-auditory health problems, such as voice strain, stress and cardiovascular diseases. Furthermore, exposure to noise at work is believed to contribute to an increased risk of workplace accidents. Recent data from the 2005 Netherlands Working Conditions Survey reveal the relation between noise, work-related stress outcomes and accidents at work.
When workers are repeatedly exposed to noise, irreparable damage to the ear may occur. Even one-off exposure to an extremely loud sound could cause damage. A considerable number of workers are at risk of being exposed to noise. In fact, noise-induced hearing loss remains one of the most commonly reported occupational diseases (European Agency for Safety and Health at Work, 2006).
The critical value for the development of hearing problems is at 80 decibels, with an A weighting filter (dB(A)). A special measurement apparatus is necessary to determine whether sound levels exceed this threshold. However, when people have to raise their voices in order to communicate at a normal speaking distance of about one metre, it is generally assumed that the noise level is above the acceptable threshold. According to the 2005 Netherlands Working Conditions Survey (Nationale Enquête Arbeidsomstandigheden, NEA) – a representative study among some 23,000 Dutch employees – 31% of the Dutch workforce (excluding self-employed people) have to talk loudly to be understood. About one out of five employees (21%) have to speak loudly sometimes, while one out of 10 employees (10%) reported that they have to speak loudly to be understood all the time. Men are exposed to noise more often than women are. Some 70% of those who regularly (sometimes or all the time) work under noisy circumstances are men.
High risk sectors
Traditionally, manufacturing and construction are the major risk sectors. Protective equipment is mandatory when noise levels exceed 85 dB(A). In the Netherlands, the employer has to provide employees with protective equipment for noise levels exceeding 80 dB(A). Figure 1 indicates that, as noted above, on average 31% of the employees surveyed need to talk loudly to be understood. However, only about 47% of the employees who are regularly exposed to harmful noise actually use protective equipment. Furthermore, Figure 1 shows the top 10 sectors at risk of harmful noise. In these high-risk sectors, at most 90% of the employees who are exposed to harmful noise actually use protective equipment.
Figure 1: Top 10 risk sectors for harmful noise, and corresponding use of protective equipment
Source: NEA, 2005
Top 10 risk sectors for harmful noise, and corresponding use of protective equipment
Detrimental health effects
Besides hearing loss and other auditory problems, exposure to noise is also identified as a source of stress among workers. In particular, noise could be a direct source of work-related stress in cognitively demanding work, involving complex tasks that require a high level of concentration. However, in most cases, noise will not be a single causal factor of stress. The extent to which noise affects workers’ feelings of stress depends on a broad range of interrelated factors, including the nature of the noise, the kind of task to be performed and personal factors such as fatigue.
Moreover, noise can be a causal factor in workplace accidents. For example, a noisy environment limits the possibilities to communicate adequately, as a consequence of which warning signs may be missed. In addition, workers can simply not hear the sound of approaching vehicles or other dangers because of surrounding noise. Noise can also increase the risk of accidents indirectly. For example, noise might cause distraction, lead to work-related stress or to tiredness, which in turn might cause human errors.
Figure 2 shows the relationship between noise exposure, on the one hand, and work-related stress and occupational accidents (leading to absence from work or not resulting in absence), on the other hand. All of these outcomes show a linear increase with noise exposure. Work-related stress was measured by the indicator of time needed to recover after work; the longer time that respondents state they need in order to relax after work, the higher their stress levels.
Figure 2: Exposure to noise, occupational accidents and work-related stress
Source: NEA, 2005
Exposure to noise, occupational accidents and work-related stress
Bossche, S.N.J. van den, Hupkens, C.L.H., Ree, S.J.M. de and Smulders, P.G.W., Nationale Enquête Arbeidsomstandigheden 2005: Methodologie en globale resultaten [Netherlands Working Conditions Survey 2005: Methodology and overall results], Hoofddorp, TNO Work and Employment, 2006.
Houtman, I., Smulders, P. and Bossche, S.N.J. van den, Arbobalans 2005: Arbeidsrisico’s, effecten en maatregelen in Nederland [Occupational health and safety balance 2005: Risks, effects and measures in the Netherlands], Hoofddorp, TNO Work and Employment, 2006.
European Agency for Safety and Health at Work, Forum 16: European noise at work summit – ‘Stop that noise’ (788Kb PDF), Bilbao, European Agency for Safety and Health at Work, 2006.
Irene Houtman and Seth van den Bossche, TNO Work and Employment