January and February 2006







By James M. Meyers, Director, California Farm Safety Program

You’re busy felling trees on a cold, wintry day, and begin feeling numbness or tingling in your fingers. You take off your gloves, look at your fingertips, and realize that they have turned pale, white or blue. When you try to unzip your jacket, you have trouble – then you pick up a small tool, and notice clumsiness with your hands that wasn’t there before.

What is happening? It’s likely that you’re experiencing symptoms of handarm vibration syndrome (HAVS), also known as “white finger,” “dead finger,” or Raynaud’s phenomenon. HAVS, commonly caused by the repeated and frequent use of chain saws and other handheld vibrating tools, is a potentially disabling condition of the fingers, hands and arms. Its most noticeable symptoms are bouts or attacks of poor blood circulation typically triggered by cold weather or by touching a cold object.

Hand-arm vibration syndrome is common in the forestry industry. In fact, the Canadian Centre for Occupational Health & Safety cites one study showing that 50 percent of 146 tree fellers examined in British Columbia had Raynaud’s phenomenon; a full 75 percent of the workers with more than 20 years experience were affected by it. Even if hand cutting is no longer a significant part of your operation, the use of chain saws or other vibrating tools in the past by you or your workers may mean that damage has already been done. The good news, though, is that by identifying the hazards that may result in HAVS – then taking steps to reduce those hazards – you can help prevent the disease from occurring in other employees and/or from progressing to a more serious stage in those who already have it.


Identifying the Hazards

One step that you can take is to choose chain saws with built-in anti-vibration features. It is important to note, however, that workers who use chain saws daily may still develop HAVS. Be sure when choosing chain saws that you ask the supplier for documented evidence that the saws do in fact reduce vibration.


Here are some more suggestions:

• Maintain the saws according to the manufacturer’s instructions. In particular, be sure that the anti-vibration mountings are changed at the specified intervals.• Provide chain saws that are fitted with heated handles.

• Provide workers with anti-vibration gloves. Although anti-vibration gloves have not been proven to be effective in preventing HAVS, those gloves that meet the international anti-vibration glove standard (EN ISO 10819) are much improved in their ability to damp vibration over earlier gloves. Choose these gloves carefully; some manufacturers have better “track records” than others. In addition to damping vibration, be sure that the gloves you choose:

•are full finger gloves (particularly when working in cold conditions). Note: While the risk of HAVS is increased by cold weather, persons working in hot climates can also suffer from HAVS.

•keep the fingers dry by wicking hand perspiration. Note: Glove liners may also do this.

• When possible, reduce the amount of time your workers use chain saws or other handheld vibrating tools. Also, encourage them to take breaks from using the tool (10 minutes per every hour of use is recommended) – or, as an alternative, to alternate tasks between vibrating and non-vibrating tools.

• Discourage smoking – the chemicals in tobacco can affect blood circulation and increase the risk or severity of HAVS.


Training Your Workers

It’s also important to train your workers to recognize the symptoms of HAVS, to report them as early as possible, and to take steps themselves to reduce their risk of contracting the disease. The following information can be passed onto your employees:

• Know the symptoms of hand-arm vibration. These may include: numbness, tingling, throbbing and pain in one or more fingers; fingertips that turn cool and pale or blue, and can go bright red; and difficulty picking up small objects and/or buttoning or zipping clothes.

• Be aware that these symptoms generally come in bouts, typically triggered by cold weather or by contact with a cold object.

• Know that tobacco use can increase the risk or severity of hand-arm vibration. Use hearing protection, and do not smoke or chew tobacco.

• Keep your hands and fingers warm. Wear anti-vibration gloves that cover all of your fingers, and make sure you have a proper fit.

• Hold chain saws and other tools as loosely as possible. Don’t excessively “grip” the tool.

• When possible, limit the amount of time you use vibrating tools. Take regular short breaks, and, when possible, alternate your work between vibrating and non-vibrating tools. The California Farm Safety Program is a cooperative effort of USDA and the University of California.




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This page was last updated on Friday, June 16, 2006