Exposure to noise in workplaces can have harmful effects on the health of workers: it causes diseases, more or less serious, that can result even in permanent hearing loss, but the noise can also contribute to exacerbate stress eand increase the risk of injury. For these reasons, it is desirable to prevent dangerous situations by installing and maintaining efficient, in workplaces, systems designed to eliminate or reduce the effects of potentially harmful sounds.

Hearing loss. The noise-induced hearing loss (NIHL) is the most common occupational diseases in Europe and is usually caused by prolonged exposure to loud noises; it starts usually with the inability to hear high-pitched sounds.
But even a brief exposure to impulsive noise (eg, firearms, or riveting, nailing ...) can cause permanent adverse effects (hearing loss, continuous ears’ buzzing). The pulses can also affect the eardrum membrane.
The loss caused by noise-induced hearing loss is permanent.

Tinnitus. The tinnitus is the auditory perception of ringing, hissing or roaring and the risk to incur it is increased by exposure to excessive noise. If the latter is impulsive (such as, for example, explosions) the risk increases substantially. Tinnitus can be the first sign of a lesion affecting the ear caused by noise.

Increased risk of accidents. The link between noise and accidents is recognized by the legal system (see below) that prescribes to take specific account during the risk assessment of the noise. The noise may be the cause of injuries because:

• makes it less audible and understandable words and acoustic signals;
• masks or cover the sound of approaching vehicles or warning signals;
• distracts workers, for example drivers;
• helps to raise the stress at work, which in turn increases the cognitive load and, consequently, the likelihood of errors.

Disorder of verbal communication. Effective communication is essential in the workplace: it will take place if the level of the conversation perceived by the ear is at least 10 dB higher than that of the surrounding noise. The workplace verbal communication limited by the intensity of ambient noise can (for example):

• force the operators to raise their voices, giving rise to problems affecting the vocal tract;
• bring drivers and mobile plant operators, in construction sites, to misinterpret verbal instructions, in some cases resulting in bodily injury.

Stress. The noise in the workplace, even when it reaches levels such as to require intervention to prevent hearing loss, may be among the causes of stress (for example, due to frequent calls or the persistent hum of machinery). The way in which the noise influences stress levels perceived by workers depends on a number of factors which includes:

• lthe nature of noise (volume, tone, predictability);
• the complexity of the operation taking place (for example, other people talking nearby when the current action requires extreme concentration);
• the psycho-physical condition of the worker (noise levels that can contribute to stress in specific situations, especially when the person is tired, can at other times be harmless).

Legislation. The minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (noise) are regulated by Directive 2003/10/EC of the European Parliament and of the Council, implemented in each Member in 2006.
According to the text of the measure, taking account of technical progress and the availability of measures to control the risk at source, "The risks arising from exposure to noise shall be eliminated at their source or reduced to the minimum." The Directive also defines the new daily exposure limit value: 87 dB.

Among the various potential causes of diseases, disorders and disabilities in the workplaces, vibrations tend to be undervalued by the operators themselves, since they do not produce an immediate impairment, but their effects on health occur only after several years and with different intensity from person to person.
The risk from vibration in reality, according to an Ispesl study, determine each year the 4-5% of occupational diseases compensated by Inail.

Control phases. The Entity responsible to carry out the tests on the level of vibrations is the employer. The standard rule distinguishes two phases for the control carried out on the extent of the level of exposure of workers.

• First phase: obligatory, requires preliminary identification of the extent of risk. There is a distinction between the vibrations transmitted to the hand-arm system and those transmitted to the whole-body, with the exposure limit and action values on a reference period of eight hours daily:

1. Hand / arm - 1. the limit value of 5 m/s2, the action value is 2.5 m/s2;
2. Whole body - 2. the limit value is 1.15 m/s2, the action value is 0.5 m/s2

• Second phase: possible, if the results of the first evaluation require it. It consists in the obligation for the employer to establish the minimum measures to reduce the technical and organizational risk for workers exposed to vibrations in excess of the action (competent doctor visits and periodic assessment)

Hand / arm vibrations Syndrome. In all fields of work activities, approximately 5% of the operators, using machinery or vibrating hand tools, is regularly exposed to vibrations affecting the hand-arm system.
The disease, called hand-arm vibration syndrome, is manifested by vascular, neurological and muscular skeletal lesions.
The first symptoms may appear only after few months or few years, depending on the subject and to the amplitude of vibrations applied to the hand.