This document examines the occupational health problems associated with the use of vibrating tools (including both hand-held vibrating tools and stationary tools that transmit vibration through a workpiece), and it provides criteria for reducing the risk of developing vibration-induced health problems. The major health problems associated with the use of vibrating tools are signs and symptoms of peripheral vascular and peripheral neural disorders of the fingers and hands. These signs and symptoms include numbness, pain, and blanching of the fingers. This composite of vibration-induced signs and symptoms is referred to as hand-arm vibration syndrome (HAVS), sometimes called Raynaud's phenomenon of occupational origin, or vibration white finger disease. In the United States, an estimated 1.45 million workers use vibrating tools. The prevalence of HAVS in a worker population that has used vibrating tools ranges from 6% to 100%, with an average of about 50%. The development of HAVS depends on many factors, including the level of acceleration (vibration energy) produced by the tool, the length of time the tool is used each day, the cumulative number of months or years the worker has used the tool, and the ergonomics of tool use. The tools most commonly associated with HAVS are powered hammers, chisels, chainsaws, sanders, grinders, riveters, breakers, drills, compactors, sharpeners, and shapers. The prevalence and severity of HAVS usually increase as the acceleration level and duration of use increase. HAVS is a chronic, progressive disorder with a latency period that may vary from a few months to several years. The early stages of HAVS are usually reversible if further exposure to vibration is reduced or eliminated; but treatment is usually ineffective for the advanced stages of HAVS, and the disorder may progress to loss of effective hand function and necrosis of the fingers. Prevention is therefore critical. Adherence to the exposure controls recommended in this document should prevent or greatly reduce the potential for vibration-exposed workers to develop HAVS.