Document dYj929wazd4yV8gVnED1bdY10

ATTENTION*. Mr. Milton frelfeld ITEM 2 4/22/76 A Mortality Study of Workor* Exposted to Vinyl Chloride April 22, 19/6 This is a report of a study of mortality rates In a population of 10,173 workers'*Who ot soma tirou In the past wore engaged In the manufac ture of vinyl chloride or Its polymers. An earlier report on a portion of this population showed that these workers experienced on Increased risk of duath from cancer of the liver (already found by other Investi gators) end concurs of the lung, brain and lymphatic system. The larger group represented In this study ha permitted a more detailed analysis of the relation between the risk of death from these causes and dura tion and level of exposures. The study population was Identified by an examination of past and present parsonnol records in 37 plants which produced either vinyl Chloride or polyvinyl chloride. Every man who had been in an exposed job for more than one year was Identified and his work history obtained. Men who had worked In the past and had quit or been laid off were traced to "determine whnthur they were still alive as of Decembrar 31. 1972, the date chosan as the "closing dote" of the study. Of the 10,173 man salected for study. 9b percent ware successfully traced, and 707 deaths wero found. The study population Included men hired as far back as thn late 1930's and Included 2.006 men who had worked IS years or more. The number of deaths which occurred was compared with the number which would hove been expected in a comparable population of United States males for ouch cause. EC- 2223 Tha total number of deaths was about 1$ percent less than expected, nd tha total number of cancer deaths was about equal to what would be expected. * Some cancers occurred at * lower rate than expected, end these did not appear to be related to the length or level of exposure. Cancer of the urinary organs and tho lymphatic system showed some excess deaths (22 percent and 1Z percent.} but wers not ^related in any systematic way to exposure. There was a 44 percent excess In leukemia deaths, also not related to tha circumstances of exposure. Lung cancer showed an 8 percent excess In the total study group, but in man who had worked for 16 years or more and had begun work at least 20 years before the closing date of the study, there was a 62 per- cunt excess. Cancers classed as '"Other and Unspeclfied" showed a dd percent ex cess in the study population as a whole, but a 230 percent excess in the older group mentioned above. This excess was lorgaly due to an excess Of -brain cancer, since 3ti percent of those cancers were brain, compared with 20 percent for the general population. There was a slight excess of digestive cancer in men with high ex posure. and In men with other than low exposure who hod worked at least 16 years beginning at least 20 years before the study date. In these older men 50 percent of the digestive cancers were liver cancer com pared with about 9 percent for tho general population. EC- 2224 ATTCTIO; Mr. Milton Fratfold !*> i* J In another analysis, the study population was scored according to tho estlniatcd total amount of vinyl chloride to which they were exposed; t tnart ware given a score of 1 for each month of low level exposure, 2 for each month at medium exposure, and 3 for each munth at high exposure. Thera was a somewhat Irregular increase in mortality from digestive cancer, respiratory cancer and cancer of other and unspecified sites with Increasing score. For men with scores of 4DP or more (equivalent to 11 years of high exposure or 33 years of low exposure, for example) the excess mortality was 88 percent for digestive cancer, 54 percent for respiratory c.neur* and 1D3 percent for c&ncors of other and un specified sites, Tho study generally confirms tne findings of earl for Investigators, Out provides additional data for men with long service whoso omploymont began many years ago. by Dr. W. R. Gaffey EC- 2225