Rewritten by John McGrane for publication in Industrial Safety & Hygiene News
Hand/Arm Vibration Syndrome:
U.S. to Follow Example of Other Countries?
U.S. to Follow Example of Other Countries?
By Thomas C. Jetzer, M.D., MPH, FACOEM
Occupational Medicine Consultants, Ltd.
& Dr. Douglas Reynolds, PhD.
University of Nevada at Las Vegas
Occupational Medicine Consultants, Ltd.
& Dr. Douglas Reynolds, PhD.
University of Nevada at Las Vegas
Employee health problems caused by vibration to the hands and arms may seem to be a new issue but it has existed since the inception of power tools. Today vibration is one of the most well documented ergonomic problems, with measurability similar to that of noise exposure.
Symptoms of vibration (usually characterized as Hand/Arm Vibration Syndrome HAVS) usually show up as a combination of finger blanching, particularly in response to cold, and progressive finger numbness. This was first defined by the Taylor-Pelmear Classification System and later refined by the Stockholm Vibration Syndrome Classification System (see tables). Unlike noise exposure, over the years it has proven difficult to provide protection against vibration. Power chainsaws, which were the first tools to bring attention to the problem of vibration-related trauma to the upper extremity, have had design improvements but percussion and other power tools have lagged in reducing the degree of vibration to which workers are exposed.
Confusion with Carpal Tunnel
One of the main differences between the United States and countries in Europe and Asia is that here we have been slower to recognize vibration trauma, usually confusing it with carpal tunnel syndrome. Most state and federal laws do not consider hand/arm vibration syndrome, or "white finger disease", to be a specific entity. It certainly has not been well recognized by the legal community which in litigation has usually lumped the malady under the category of carpal tunnel. It's only in the past five to ten years that worker compensation suits have made vibration trauma a larger issue in the U.S. Interestingly, the growing awareness of the problem in this country emerged more often from product liability suits against the tool manufacturers. While there were flurries of research into vibration trauma in the United States during the '70s, no specific conclusions were drawn. NIOSH did issue a Criteria Document that outlined the history of hand/arm vibration syndrome problems.
In 1986, the International Standards Organization (ISO), which is comprised of member countries primarily from North America, Europe and Asia, passed ISO Standard 5349. The American National Standards Institute (ANSI) in the U.S. passed ANSI Standard S3.34 the same year. These standards specified procedures for measuring and quantifying vibration transmitted to the hand, and they gave recommended guidelines for assessing and controlling vibration that is transmitted into the hand. They implied that less vibration along with less time exposure would lead to less likelihood of developing HAVS. Not surprisingly, this caused employers to address the problem either by restricting the amount of time using the vibrating tool or switching to tools that operated with less vibration.
Efforts to develop personal protection equipment as a solution to vibration have been spotty. Initially, the emphasis was on protecting the hand from cold, i.e. wearing gloves. Then a series of viscol-elastic materials, basically Sorbothane and Viscolas, were used in gloves as a means of addressing vibration specifically. While these gloves did provide some degree of protection against impact and vibration in the high vibration frequencies, they provided little or no protection in the lower and middle frequencies. Another concern with these gloves was that they were so bulky and/or stiff that they required extra grip exertion in order to control the tool. This is ergonomically undesirable and may actually increase other hand problems, such as carpal tunnel syndrome and tendonitis. This problem is especially true with lower quality gloves.
Protection Standards Abroad
The European countries recognized quickly that the anti-vibration gloves then on the market really did not meet the criteria of protection needed. On that basis, in the early 1990s an ISO Committee working group developed ISO Standard10819 which was adopted by all participating countries. This standard defines the performance criteria for anti-vibration gloves and puts rather stringent requirements in both mid and high frequency transmission for certification as an anti-vibration glove. Essentially, this standard says that at the mid frequencies, the glove cannot transmit more than 100% of the vibration, and at high frequencies it cannot transmit more than 60%.
At the time, the consensus was that the standard would be difficult to meet, and people in the anti-vibration field worried whether it would ever be possible to develop personal protection equipment that would provide significant protection. The good news for the worker is that recent technological developments have resulted in new glove designs that are meeting the standard.
A point of interest . . . and one that may change the scope of concern in this country . . . is the NIOSH document 97-141 on cumulative trauma and work exposure. Issued in July 1997, this document essentially defined the relationship of various musculoskeletal injuries as they relate to the workplace. It is significant in that it clearly states "there is strong evidence" that the use of vibrating tools causes hand/arm vibration syndrome.
In its review of literature, document 97-141 also noted that vibration can also be a significant causative factor in developing carpal tunnel syndrome. In fact, in the Ergonomic Guidelines for the Meat Packing Industry in 1991, OSHA 3123 defined vibration as a significant causative factor to upper extremity accumulative trauma. However, NIOSH 97-141 goes much further with deeper literature support. These findings are very important in that people in this country who use vibrating tools may finally have support not only for the more rare "white finger" syndrome, but indeed now for the more common carpal tunnel syndrome with which the public is more familiar. There does seem to be a rising awareness in our general population, as well as in the legal community, that vibration is a causative problem for compensable injuries.
Prepare Now for New Standards
These developments have increased awareness of the need to protect against vibration. It's estimated that in the U.S. between two and four million people are exposed to some level of hand/arm vibration on the job.
It is anticipated that a proposed new ANSI ergonomic standard will address issues associated with hand-arm vibration in a more comprehensive manner. The point is, we can expect public awareness of hand/arm vibration syndrome to continue to grow here in the U.S. And American industry should prepare now to meet future standards and awareness the way overseas companies have been trying to: via decreased tool vibration or increased personal protection.
(Dr. Jetzer is a practitioner in occupational medicine, and a member of the USA Technical Advisory Group to ISO/TC108/SC4, Human exposure to mechanical vibration and shock. Dr. Reynolds is a professor of mechanical engineering and chairman of the USA Technical Advisory Group to ISO/TC 108/SC4.)
Symptoms of vibration (usually characterized as Hand/Arm Vibration Syndrome HAVS) usually show up as a combination of finger blanching, particularly in response to cold, and progressive finger numbness. This was first defined by the Taylor-Pelmear Classification System and later refined by the Stockholm Vibration Syndrome Classification System (see tables). Unlike noise exposure, over the years it has proven difficult to provide protection against vibration. Power chainsaws, which were the first tools to bring attention to the problem of vibration-related trauma to the upper extremity, have had design improvements but percussion and other power tools have lagged in reducing the degree of vibration to which workers are exposed.
Confusion with Carpal Tunnel
One of the main differences between the United States and countries in Europe and Asia is that here we have been slower to recognize vibration trauma, usually confusing it with carpal tunnel syndrome. Most state and federal laws do not consider hand/arm vibration syndrome, or "white finger disease", to be a specific entity. It certainly has not been well recognized by the legal community which in litigation has usually lumped the malady under the category of carpal tunnel. It's only in the past five to ten years that worker compensation suits have made vibration trauma a larger issue in the U.S. Interestingly, the growing awareness of the problem in this country emerged more often from product liability suits against the tool manufacturers. While there were flurries of research into vibration trauma in the United States during the '70s, no specific conclusions were drawn. NIOSH did issue a Criteria Document that outlined the history of hand/arm vibration syndrome problems.
In 1986, the International Standards Organization (ISO), which is comprised of member countries primarily from North America, Europe and Asia, passed ISO Standard 5349. The American National Standards Institute (ANSI) in the U.S. passed ANSI Standard S3.34 the same year. These standards specified procedures for measuring and quantifying vibration transmitted to the hand, and they gave recommended guidelines for assessing and controlling vibration that is transmitted into the hand. They implied that less vibration along with less time exposure would lead to less likelihood of developing HAVS. Not surprisingly, this caused employers to address the problem either by restricting the amount of time using the vibrating tool or switching to tools that operated with less vibration.
Efforts to develop personal protection equipment as a solution to vibration have been spotty. Initially, the emphasis was on protecting the hand from cold, i.e. wearing gloves. Then a series of viscol-elastic materials, basically Sorbothane and Viscolas, were used in gloves as a means of addressing vibration specifically. While these gloves did provide some degree of protection against impact and vibration in the high vibration frequencies, they provided little or no protection in the lower and middle frequencies. Another concern with these gloves was that they were so bulky and/or stiff that they required extra grip exertion in order to control the tool. This is ergonomically undesirable and may actually increase other hand problems, such as carpal tunnel syndrome and tendonitis. This problem is especially true with lower quality gloves.
Protection Standards Abroad
The European countries recognized quickly that the anti-vibration gloves then on the market really did not meet the criteria of protection needed. On that basis, in the early 1990s an ISO Committee working group developed ISO Standard10819 which was adopted by all participating countries. This standard defines the performance criteria for anti-vibration gloves and puts rather stringent requirements in both mid and high frequency transmission for certification as an anti-vibration glove. Essentially, this standard says that at the mid frequencies, the glove cannot transmit more than 100% of the vibration, and at high frequencies it cannot transmit more than 60%.
At the time, the consensus was that the standard would be difficult to meet, and people in the anti-vibration field worried whether it would ever be possible to develop personal protection equipment that would provide significant protection. The good news for the worker is that recent technological developments have resulted in new glove designs that are meeting the standard.
A point of interest . . . and one that may change the scope of concern in this country . . . is the NIOSH document 97-141 on cumulative trauma and work exposure. Issued in July 1997, this document essentially defined the relationship of various musculoskeletal injuries as they relate to the workplace. It is significant in that it clearly states "there is strong evidence" that the use of vibrating tools causes hand/arm vibration syndrome.
In its review of literature, document 97-141 also noted that vibration can also be a significant causative factor in developing carpal tunnel syndrome. In fact, in the Ergonomic Guidelines for the Meat Packing Industry in 1991, OSHA 3123 defined vibration as a significant causative factor to upper extremity accumulative trauma. However, NIOSH 97-141 goes much further with deeper literature support. These findings are very important in that people in this country who use vibrating tools may finally have support not only for the more rare "white finger" syndrome, but indeed now for the more common carpal tunnel syndrome with which the public is more familiar. There does seem to be a rising awareness in our general population, as well as in the legal community, that vibration is a causative problem for compensable injuries.
Prepare Now for New Standards
These developments have increased awareness of the need to protect against vibration. It's estimated that in the U.S. between two and four million people are exposed to some level of hand/arm vibration on the job.
It is anticipated that a proposed new ANSI ergonomic standard will address issues associated with hand-arm vibration in a more comprehensive manner. The point is, we can expect public awareness of hand/arm vibration syndrome to continue to grow here in the U.S. And American industry should prepare now to meet future standards and awareness the way overseas companies have been trying to: via decreased tool vibration or increased personal protection.
(Dr. Jetzer is a practitioner in occupational medicine, and a member of the USA Technical Advisory Group to ISO/TC108/SC4, Human exposure to mechanical vibration and shock. Dr. Reynolds is a professor of mechanical engineering and chairman of the USA Technical Advisory Group to ISO/TC 108/SC4.)