IOEM workshop focuses on health risk management

The 2006 annual IOEM workshop included a plenary session on health surveillance for noise and vibration health hazard control.

The annual workshop of the Institute of Occupational and Environmental Medicine (IOEM), held in Birmingham every autumn, is one of the largest and most multi-disciplinary events of the occupational health calendar, bringing together OH managers and physicians from a wide range of backgrounds.

The director of the IOEM, professor Jouni Jaakkola, chose a general health promotion theme with which to open the 2006 event. He briefly reviewed the best and worst situations within the EU regarding workplace exposure to environmental tobacco smoke (ETS), contrasting the situation in Spain, where around half the population are still exposed to ETS in workplaces on a daily basis, with Sweden, where just 3%-10% are exposed. The figure is between 11% and 24% in Britain.

Jaakkola congratulated the UK government on the Health Act and banning workplace smoking in England (from 1 July), which he described as "one of the greatest achievements of both occupational and general health policy".

Noise and vibration health hazard control

A plenary session devoted to the recently introduced Control of Noise at Work Regulations and the Control of Vibration at Work Regulations was the most directly relevant to occupational health specialists. The session included an overview of the regulatory requirements by Bruce Appleton, noise specialist at the Health and Safety Executive (HSE), and a review of best practice in control from Peter Wilson, director of the Industrial Noise and Vibration Centre (INVC), Slough.

The HSE launched a noise and hand-arm vibration (HAV) control campaign in July 2006, focusing on sectors with the highest exposure risks, such as construction foundries and heavy steel fabrication. More than 2 million UK workers are exposed to one or other hazard, and related health effects account for 50% of successful new industrial injury compensation claims and for more than 50% of civil compensation claims for occupational disease. The HSE's website provides comprehensive information on noise and vibration, and on how to comply1,2 with the Regulations.

Noise-control audits

"Noise control is not a safety issue; it is an engineering problem that should be solved by engineering means, particularly through noise control at source," Wilson said. He argued that there needs to be a new attitude towards noise and vibration control, with solutions based on accurate diagnosis and costing of options. All options need to be considered, not just the conventional high-cost palliatives of enclosures and silencers, which should be used only where there are no feasible engineering solutions.

According to Wilson, innovative engineering noise-control techniques are often much cheaper than conventional approaches. By introducing a best-practice approach based on finding simple engineering solutions to common problems, such as fans and pneumatics, and by implementing appropriate purchasing policies, significant savings can be made and productivity improved.

Noise control, rather than noise measurement, is at the heart of the new Regulations. Hearing protection can no longer be used for long-term risk management unless it can be shown that noise control at source is not practicable.

Similarly, only where engineering control is not practical for the dominant source is acoustic screening/enclosure an acceptable option.

Wilson advocates that companies introduce a noise-control audit instead of repeat risk assessments. Such audits should involve:

  • listing all potential noise sources for each piece of noisy plant;

  • ranking the sources; and

  • assessing all noise-control options for the dominant noise source, taking into account operational, productivity and hygiene constraints, as well as operator acceptance and cost.

    By generating "noise reduction versus cost" trade-offs for each item of noisy plant, a cost-effective noise-control programme can be put in place. The key is to ensure that the dominant source is treated first, otherwise overall noise reductions are likely to be disappointing. A holistic approach to noise control reaps other benefits, in addition to direct reductions in noise emissions. Cadbury, for example, has reported a 12dB(A) reduction in noise emissions and a 20% reduction in air consumption from its noise-control programme. Pioneering solutions such as Quiet Fan technology (QFt), which involves modifications to internal fan components, can produce large savings for employers. In one company, the introduction of QFt reduced overall fan noise from scrap-can extract and chopper fans by 22dB(A) at a cost of just £3,000 (£100 per fan), making a saving of £35,000 on the capital costs of fitting conventional acoustic enclosures and silencers and with the additional benefit of no ongoing maintenance costs.

    Probably the single most cost-effective noise-control measure, said Wilson, is the adoption of "buy quiet" and "buy/hire smooth" purchasing policies to ensure that noise and vibration problems are avoided before the installation of machinery. Such policies generate commercial pressure to develop a quiet plant that operates to best-practice standards. However, many suppliers do not have expertise in noise and vibration control, he cautioned, and so should be kept under scrutiny to ensure that they deliver to specification.

    Health surveillance - noise

    Health surveillance is a key regulatory requirement, for both noise and HAV. The aim of surveillance is to detect adverse health effects at an early stage, identify and protect at-risk employees, check the effectiveness of control measures, prevent progression and provide feedback on the effectiveness of risk assessment. Dr Ian Lawson, chief medical officer at Rolls-Royce, provided an overview of the noise and vibration Regulations' health surveillance requirements, stressing that a policy on health surveillance for both noise-induced hearing loss and HAV must be in place before the implementation of a programme, and should include provisions on the management of affected employees.

    Health surveillance is required:

  • at pre-employment/pre-placement screening in order to get baseline data;

  • where there is a risk to health; and

  • when exposure is above certain thresholds.

    (See Health surveillance under the Noise at Work Regulations.)

    Health surveillance - vibration

    There is no audiometry equivalent for HAV syndrome diagnosis (although the HSE views vibrotactile and thermal threshold tests as useful in making fitness-to-work decisions). Health surveillance for HAV syndrome generally involves screening by questionnaire to assess employees' previous and current exposure to noise and vibration, their health status and any additional risk factors. There are a number of screening levels:

  • Tier 1: initial screening questionnaire for those starting jobs that involve exposure to vibration (responses to the questionnaire will determine whether referral for a Tier 3 HAV assessment is necessary).

  • Tier 2: screening questionnaire issued once a year to employees exposed to vibration risks (responses to the questionnaire will determine whether referral for a Tier 3 HAV assessment is necessary).

  • Tier 3: HAV health assessment by a qualified person, such as an occupational health nurse (referral to Tier 4 is made where the assessment indicates that the employee has HAV).

  • Tier 4: formal diagnosis of HAV by a doctor, usually an occupational physician.

    Advice for employers and occupational professionals on HAV health surveillance, along with examples of questionnaires, can be downloaded from the HSE's website3.

    Need for expertise

    Evaluation of health surveillance data for noise and vibration requires experience and good clinical judgment to assess the severity of any impairment. For noise-induced hearing loss, this ranges from acceptable hearing through to rapid hearing loss and, for HAV, from no symptoms (stage 0) to constant numbness and/or tingling (stage 3). Employee health surveillance records, with details of exposure and screening outcomes, need to be kept. Anonymised information needs to be made available to enable the employer to assess the effectiveness of control measures and to target noise-reduction initiatives more accurately. There should be no difficulties with regard to disclosure of information, according to Lawson, because personal medical information remains confidential and should be kept separately from the health surveillance records.

    1. www.hse.gov.uk/noise/index.htm

    2. www.hse.gov.uk/vibration/index.htm

    3. www.hse.gov.uk/vibration/hav/advicetoemployers/healthsurveillance.htm