The Health and Safety Executive (HSE) estimates that nearly 2 million workers in the UK are at risk of developing Hand Arm Vibration Syndrome, also known as HAVS. Any worker, in any industry, who regularly uses vibrating power tools (examples include; drills, chainsaws, strimmers and jack hammers) is at risk of developing HAVS. Extended periods of tool use increase a worker’s level of exposure to vibration and so increase the risk of developing HAVS.
The legal bit
The Control of Vibration at Work Regulations 2005 is in place to protect workers from the risks to their health and safety from exposure to vibration. It aims to reduce the risk of a worker developing HAVS and to prevent those that already have established HAVS from developing more severe symptoms. The regulations highlight 2 limit levels:
- The Exposure Action Value of 2.5m/s2 A(8) or 100 points on the HSE ready reckoner scale, which recommends that employers look at organisational measures to reduce vibration exposure.
- The Exposure Limit Value of 5.m/s2 A(8) or 400 points on the HSE ready reckoner scale, the vibration limit that should not be exceeded by any worker.
Employers are encouraged to evaluate the vibration levels produced by their equipment. The above levels can then be calculated by using the HSE’s HAVS ready reckoner, which informs an employer how long a worker can use equipment for their job during a working day. For more information, see www.hse.gov.uk/vibration/hav/readyreckoner.htm
If a case of HAVS and/or Carpal Tunnel Syndrome associated with vibration exposure has been diagnosed, it should be reported by the employer under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR) 1995.
What are the effects of vibration on the hands?
Vibration can have effects on the blood vessels and nerves in the hands. Either just the blood vessels or nerves can be effected. Sometimes the blood vessels and nerves are effected at the same time. It is not possible to predict how a worker will be affected by vibration. Vibration exposure can cause serious and disabling symptoms. HAVS is preventable but when it has developed, it is permanent.
What are the symptoms of HAVS?
The effects on blood vessels cause problems with circulation to one or more fingers of one or both hands. This can result in episodes of Raynaud’s phenomenon, known also as “white finger”. This is an episodic, painful condition, usually triggered by cold conditions.
The effects on the nerves of the hands causes problems with sensation. Numbness and/or tingling can result. If the condition progresses, manual dexterity, with the ability to perform simple tasks such as picking out coins from a wallet can be difficult.
Some people notice discomfort and reduced grip strength in their hands, although these symptoms on their own do not lead to a diagnosis of HAVS.
Vibration exposure has also been weakly linked to developing a separate condition called Carpal Tunnel Syndrome, which could potentially arise at the same time as HAVS. For more information on this condition, please see www.hse.gov.uk/vibration/hav/statistics.htm
How can an employer help to prevent an employee from developing HAVS?
Health surveillance is used to help identify and respond to early signs of symptoms and possible damage as a result of vibration exposure. It also aims to check the efficacy of control measures that are in place in the working environment. However, the most important measure is for companies to look at their working practices and to try and reduce or eliminate sources of vibration. Workers should be provided with tools that are fit for their intended use, well maintained and that emit the lowest source of vibration possible. Workers should also be trained to use the equipment safely.
The HSE recommends that any worker exposed to sources of vibration above the Exposure Action Value of 2.5m/s2 (or 100 points) should undergo health surveillance. This is also recommended for workers who only occasionally use vibrating tools but who are likely to exceed the Exposure Action Value. Health surveillance is also recommended for those workers who have already been diagnosed with HAVS, even if their level of vibration exposure falls below the Exposure Action Value.
A tiered process is followed in the health surveillance process:
Tier 1: The baseline assessment before a worker is exposed to any vibration. The minimum requirement is a self-administered health questionnaire, to be returned to the Occupational health provider for review.
Tier 2: Screening questionnaire, repeated annually for those workers who are vibration exposed but who have not previously declared any symptoms. A responsible person within the company can administer the questionnaire but many companies process the questionnaires through their occupational health provider for confidentiality purposes.
Tier 3: A more detailed assessment by a qualified person, usually an occupational health nurse, which collects more information about symptoms and a physical examination. It is used for workers who have indicated symptoms on the Tier 2 questionnaire. This can help guide diagnosis but a Tier 4 assessment by a HAVS qualified doctor is required to make a formal diagnosis.
Tier 4: A detailed assessment by a HAVS qualified doctor. This is to provide a formal diagnosis, advice regarding RIDDOR reporting and advice regarding fitness for work. The doctor takes a detailed description of symptoms reported by the worker and conducts an examination to assess circulation (blood pressure, tests to exclude other circulatory causes of symptoms), sensation (using equipment to detect touch) and grip strength/manual dexterity. Tests are not invasive or uncomfortable and are used to help determine the severity of HAVS. The symptoms reported by the worker are the most helpful for establishing a diagnosis of HAVS and an examination can be normal in workers with early stages of HAVS.
Tier 5: This is an optional measure, beyond the scope of most occupational health providers. This process can be expensive and currently no test is robust enough to confirm a diagnosis of HAVS with the final diagnosis still depending on the judgement of the Doctor and will still need to take account of the reported symptoms. For this reason, most organisations seek a diagnosis through Tier 4 assessment only.
For more information about HAVS, please see http://www.hse.gov.uk/vibration/hav/