Whole lotta shakin’

Vibration-producing hand tools can actually get on your nerves and cause permanent damage. Prevention is the key.

Power tools that produce vibration can cause hand and arm injury, according to the experts at Labor Occupational Health Program (LOHP) at the University of California/Berkeley.

Workers may think the tingling, pain or numbness they feel when using vibrating tools is just part of the job, but vibrating tools like drills, jackhammers, grinders and chainsaws can cause serious health problems that could force them to leave their chosen trade.

The injury is called Hand-Arm Vibration Syndrome (HAVS) and the LOHP reports that of the millions of U.S. workers who use vibrating tools, more than half of them will get some form of HAVS over time. That’s why the LOHP put together a tailgate talk on the hazard.

This article is based on that information which focuses on California OSHA’s requirements. State or federal requirements may vary, but LOHP’s general recommendations offer good advice to head off this debilitating injury.

Injuries are exposure-related
The risk of injury partly depends on the amount of vibration the tool produces, how long a worker uses the tool each day over how many total hours, months, and years. How a worker holds the tool also affects the risk factor.

Some workers may have symptoms just a few months after they start using vibrating tools, but others may not have any trouble for a long time. However, once hand-arm vibration syndrome (HAVS) is established, it may be too late to reverse it. Full use of fingers may be lost. Therefore, the best treatment is prevention.

How vibration gets on your nerves
Tool vibration can damage the blood vessels in hands and fingers, which in turn reduces the blood supply and harms the skin, nerves and muscles. The loss of feeling in hands and fingers and inability to control them is called HAVS, but it’s also known as white finger, dead finger, or Raynaud’s Syndrome.

It’s very important to watch for early symptoms and report them. Early symptoms include tingling fingers; numbness; fingertips that turn white or blue; clumsiness with hands; trouble picking up small objects; trouble buttoning and zipping clothes and reduced sense of heat, cold and pain in hands.

Your chance of getting HAVS goes up if you’re exposed to vibration combined with other risk factors that also cut down the blood supply. Research shows that exposure to cold, loud noise and/or tobacco smoke increase the risk of HAVS.

Heading off HAVS
Reducing exposure to vibration as well as the other risk factors can head off HAVS. Although gloves with vibration-dampening material built into the palms and fingers are available, they haven’t been proven to be effective. But if they fit well and don’t require a tighter grip on the tool, it doesn’t hurt to try them.

Because cold working conditions can increase your risk, it’s important to wear regular work gloves and warm clothing to avoid getting your hands cold or wet.

Most vibrating tools are loud, and exposure to loud noise increases HAVS risk. It’s important to wear hearing protection while using them. Finally, always wear safety glasses or other eye/face protection when you work with any tool.

Tool selection can help reduce your risk of HAVS. Can the work be done with a non-vibrating tool? For example, can a part can be milled or machined instead of ground into shape with a grinder?

Look for tools that have vibration-dampening features. Some new designs can reduce tool vibration by more than 50 percent. Ask tool suppliers for real evidence on their claims that their equipment reduces vibration.

Good tool maintenance can help reduce vibration exposure. Tools that are worn, blunt, or misaligned produce more vibration. These tools should be serviced or bits or blades replaced to function more efficiently.

Controlling exposure to vibration is an effective way to reduce the HAVS hazard. Limit the amount of time any one worker uses a vibrating tool. Take a 10-minute break for every hour spent working with a vibrating tool or alternate work with vibrating and non-vibrating tools.

Let the tool do the work. That allows the worker to use less gripping force while still keeping control of the tool. A tight grip restricts blood flow and also transmits more vibration from the tool to the body. Finally, don’t use full throttle unless it’s absolutely necessary.

Worker follow-up
Presently, no exams are required by law, but it’s a good idea for anyone exposed to hand-arm vibration on a regular basis to have an annual exam for signs of HAVS. The exam should be conducted by a medical professional with special training in occupational health.

Any worker who experiences tingling or numbness should inform his or her employer and request a medical evaluation.

Published in the November/December 2004 issue of Contractor Tools and Supplies magazine.

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