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Dear Editor .. of all cases of angiosarcoma of the liver due to vinyl chloride exposure ' Over the past several weeks, is maintained. As of 1988, there there have been references in the paper both in news stories and had been 138 cases in the world including 79 in Europe and 50 in letters to the editor regarding vinyl chloride. Some of these statements , North America. There have been no have been erroneous, and I think it might be helpful to your readers to review what is known about the health effects of vinyl chloride. The health effects of vinyl chloride have been well documented in the medical literature and can be divided into acute effects (those due to short term exposure) and chronic effect of vinyl chloride is anesthesia which occurs in individuals exposed to levels in the 8,000 to 10,000 ppm (parts per million) range. This would be approximately one percent cases of angiosarcoma of the liver in vinyl chloride workers in Louisiana. In 1976, the Occupational Safety and Health Administration established a limit of one ppm for exposure to vinyl chloride in the workplace. All of the previously described acute and chronic health effects occur only at exposures of hundreds of thousands of ppm. Questions have been raised about the possibility that vinyl chloride causes other types of cancer in concentration. The chronic effects workers or in people who live in of vinyl chloride exposure include effects on blood vessels, skin, bone, and liver; and the rare cancer, the vicinity of a vinyl chloride plant. Sir Richard Doll, a noted English epidemiologist, published a angiosarcoma of the liver. All of these effects are seen only in comprehensive study in 1988 of the health effects of vinyl chloride. He individuals who have been exposed to levels of hundreds of parts per reviewed all the available literature on the subject and focused on four million over many years." In the 1940's and 1950's it was believed that vinyl'chloride was not dangerous, and that ' the only concern was its anesthetic effects on primary studies which included over 17,000 vinyl chloride workers. Two of his conclusions weire: 1) "The facts are outstanding. First, the men have experienced a specific hazard of the central nervous system. During a type of cancer that is normally these years workers who cleaned- reactor'Vesselsin vinyl /chloride polymerization;t plants1 were bphs&entjy 'expopedto levels of "extremely rare,' namely., angiosarcoma bf the liver." and 2) ^"The second outstanding . observation is that the mortality of exposed men, other than that ;jdue tp angiosarcoma of the liver is ikvelopedchanges in the' L typical of the normally healthy vessels in the extremities, the Industrial worker - that is not to say skin, the bones of the fingers, and that no other hazard exists, but that enlargement of the liver. In 1974, a the effect of any other hazard is rare form of cancer, angiosarcoma bf the liver, was found to occur small." By this, Doll is saying that while it is impossible to ever state more frequently in workers at vinyl with absolute certainty that no chloride polymerization plants who other hazard is present, if any other had experienced long term high health hazard does exist, it is so levels of exposure to vinyl chloride. small as to be undetectable. This tumor can also be caused by In addition, Doll looked at the exposure to anabolic steroids (drugs used by some athletes to enhance performance) and Thorotrast (an x- question of whether there is any health effect on people living near vinyl chloride facilities and ray contrast material which is no concluded: "According to any longer used), A worldwide registry reasonable criterion the hazard to the general public (if there is any at looked at the question of possible all) must be negligible." Doll also increase brain and lung cancer due looked at the question of possible to vinyl chloride exposure. There increased brain and lung cancer due have been articles published which to vinyl chloride exposure. Based on all the data available, Doll did not conclude that there was an. increased risk of these cancers. Studies have also been done to address the possible reproductive effects of exposure to vinyl chloride. These studies have concluded that there is noincreascd rate of birth defects related to vinyl chloride exposure in populations living near vinyl chloride facilities, and there is no evidence of an increase in miscarriage rates due to vinyl chloride. One study done by Infante et. al. in 1976 suggested the possibility of an increase in miscarriage rates related to vinyl chloride, however, this study has been discredited by the academic community due to improper analysis of the data. TTie health effects which have been seen have occurred in workers exposed prior to 1975 to very high levels of vinyl chloride over many years. These levels were in the hundreds to thousands of parts per million. Since the mid*1970's, the exposure levels for vinyl chloride . workers have been dramatically reduced. At. Dow's Louisiaha Division facility, personnel and vea monitoring for vinyl chloride haYe consistently been below one ppra\ These measurements have been made in the vinyl chloride plant in those areas of the plant with the highest potential for vinyl chloride exposure. In addition, computer aided models liaye.been, used (p estimate the maximum predicted concentrations of vinyl chloride in immediately surrounding communities based on levels of. emission from Dow,'Occidental! and B.F. Goodrich. These maximum predicted concentrations for the community are less than one one-hundredth of the' OSHA workplace exposure limit Based on all this information, I agree with the conclusion reached by Doll that the risks of health effects in the community due to vinyl chloride, if present at all, must be negligibly Geoffry D. Kusch, M.D. Senior Occupational Health Physician Dow USA, Louisiana Division