Document GmM4m567Nxb6zGBzaYv08rN5n

ROSENMAN STUDY 9/81 \ Mortality Experience of a Cohort of Vinyl Chloride Polymerization Workers and A Cohort of Polyvinyl Chloride Fabrication Workers Barkaround In 1931, Monsanto purchased tho FiberIold Corporation and moved to its present site in Springfield, Massachuuetts* At that time-the plant complex, which had been operating since 1901, employed about 900 workers on an SO acre site, and was Involved in the production of Fibestos (cellulose acetate), Fiberloid (cellulose nitrate), Safelex (polyvinyl butyral), Vuepak (cellulose ecetate film), Fibestos (cellulose Acetate molding powders), and Fiberlac (lacquers). Monsanto rapidly expanded its new plastics division over the next decade. In 1940, a new plant for the manufacture of Rcsinox (phenol formaldehyde) was build at the Springfield site. 'In 1946, the plastics division again expanded its facilities and began producing Lustrex, Monsanto's polystyrene plastic. Over the next several years about 100 acres of adjacent land was purchased on whidi three new buildtnp were erected in the late 1940's for the manufacture of OpaJon resin and Ultron film and compound (polyvinyl chloride) and Resamine (melamines). In 1973, a group of Monsanto employees and a Massachusetts ftiystdan reported to N1QSH that a preliminary study of Monsanto employees indicated an overall excess of cancer deaths and an excess of deaths from cancer of the pancreu. In response to this report, NIOSH Initiated a mortality study of 463 deaths among male employees who were eligible for death benefits during 1930 through April, 1976. Results of this study Indicated an elevated proportion of deaths due to cancer of the digestive organa and the genitourinary tract (1). Monsanto also performed an Independent mortality study using 364 deaths observed from 1930 through 1976. Results of this study indicated a significant excess in the number of deaths from arteriosclerotic heart disease. The Monsanto study demonstrated a small, non*significant ina'case In digestive and genitourinary cancers (3). As a reside of these proportional mortality studies, the University of Pittsburgh, under contract with the Monsanto Company, performed a historical cohort study among employees and ex-employees of the Monsanto-Sprlngfieid Plant. The cohort consisted of 2490 male workers with at least one year of employment as a wage earner between January 1,1949 and December 31, 1966. Mortality experience of the cohort was examined from January 1,1949 through December 91, 1976* Based on Hampden Couity comparisons, elevated S'tandarited Mortality Ratios (SMR's) were observed for all digestive cancers, and many specific sitas of the digestive tract. Although not statistically significant^ most of these increases showed evidence of a relationship with duration and time from onset of employment, as well as calender year of death. In addition, significantly elevated SMR's were observed for genitourinary tract cancers, coronary heart disease, and influenza and pneumonia 01. None of tho previous studies have examined mortailty'by worksite. The lack of this particular type of analysis decrease the chance of uncovering any Increased mortality from occupational exposure at this plant. UCC 085646 ROSENKA.S STUDY 9/81 Discussion V The mortality experience of a group of vinly chloride exposed and polyvinyl r' chloride exposed workers was analysed `Hie results indicate that there was excess mortality in both these groups. There was one death dUe to hemangiosareoma of the liver among workers polymerizing vinyl chloride. In addtfon, th re was a statistically significant Increase in buccal cancer with three observed deaths (Table *). All malignant neoplasms, cancer of digestive organs and lymphatic cancers were Increased although the inoease was not statistically sipificim (Table 4). Among the polyvinyl chloride fabricators, Hodgldns disease was statistically Increased All malignant neoplasms, digestive cancers and respiratory cancers were increased but not to statistically significant levels (Table 9L Supporting the occupational nature of the lnaeases foud was the positive trend o( the SMRs with time since first exposure for all malignant neoplasms, digestive cancer (or both cohorts (Figure 1 and 2) and respiratory cancer for the polyvinyl chloride cohort (Figure 2). The three latency periods since first exposure for the three men who died of buccal cancer in the rinyl chloride cohort were 21, 23 and 23 years respectively and 20 and 23 years for the two workers dying of Hodgkins disease in the polyvinyl diloride cohort. Six previous reports of workers exposed to vinyl chloride have documented an increased risk of fiver, ling, brain and hematolymphatic cancer (7-12). One previou* study has also found an inaease In buccal cancer although In that report there was inverse relationship with exposure (11). There have been two previous reports on polyvinyl chloride fabricators (12, 13). One study found an increase in stomach cancer, the other increased digestive cancer in men and women and breast and urinary organs In women. The unexpected finding In our study was the elevated risk of lung cancer In ^ polyvinyl chloride workers but not vinyl chloride workers. Possible explanations for these findings include (1) the method of cohort development whereby individuals with vinyl chloride exposure maybe in the polyvinyl cohort (2) vinyl chloride monomer contamination of the polymer (3) adverse effect of one of the many additives used in this work area , or (4) other cordoundng factors Q.e. cigarette smoldng). Cigarette smoidng is probably not the reason as there was less normallgant respiratory disease than expected. However, the issue is douded by the fact that previous reports of ino'eased lurg and lymphopoietic cancer In vinyl chloride workers were based on studies of workers exposed to both vinyl chloride and polyvinyl chloride. The results of this study reinforce the importance of examining large occupational cohorts by specific departments or exposure so as to be able t ascertain adverse efforts among subsets with specific work histories. The findings of excess mortality for sped fie causes among workers exposed to vinyl chiorid or polyvinyl chloride were not evident In previous studies done on workers from the whole planl. Despite the problems with development o( this cohort we feel that the results of this study demonstrate excess mortality among workers exposed to vinyl chloride and polyvinyl chloride. The long latency periods since first exposure in these cohorts (more than 10% of the cohort greater than 20 year latency) make continued follow up of this group Important. Also the possibility of medical screening for this group of workers at increased risk needs to he considered An even better ascertainment of individual work histories and approximate levels of exposures Is necessary to assess the health effects ef polyvinyl chloride in the absence of exposure to the monomer. UCC 085647