Document VKEOeY4RLQj6Qe1MnjLnN71xg

EPIDEMIOLOGICAL STUDY OF VINYL CHLORIDE WORKERS FINAL REPORT W" Prepared for Manufacturing Chemists Association 1825 Connecticut Avenue, N.W.'_ Washington, D.C. 20009 Prepared by Equitable Environmental Health, Inc. 6000 Executive Blvd,, Suite 308 . Rockville, Maryland 20852 ' ' V .. v ' January, 1978 GTR35 CONTENTS I. INTRODUCTION II. PLANTS INCLUDED IN STUDY III. STUDY POPULATION A. Identification B. Follow-up C. Description IV.EXPOSURE LEVELS V. CALCULATIONS OF MORTALITY VI. STANDARDIZED MORTALITY RATIOS A. For the Total Population B. For the Population Groupedby Maximum Estimated Exposure Level C. Consideration of Duration, Time of Exposure, and Maximum Exposure D. Integrated Doses E. Analysis of Long-term PVC Production Workers VII. SELECTED GROUPS OF DEATHS VIII. DISCUSSION IX. SUMMARY & CONCLUSIONS Page 1 3 4 4 5 7 8 10 13 13 13 14 16 17 18 21 GTR36 IX. SUMMARY & CONCLUSIONS This is the final report of a study of the mortality of workers exposed to vinyl chloride and its polymers, which augments studies reported in 1974 and 1975. The current report increases the total population of workers studied from 8,384 to 10,173, with the number whose vital status was deter mined increasing from 7,128 (85 percent) to 9,677 (95.1 percent). The number of deaths has more than doubled; there are now 669 certified and available for analysis, compared with 328 in the original study. The follow up period concluded December 31, 1972, for both the original study and the augmented final study. The successive additions to the population and improved follow-up have been accompanied by a rise in the overal1-cause Standardized Mortality Ratio (SMR) from 75 in 1974 to 89 in the current analysis. The major change has been in the SMR for cardiovascular and renal disease, which was originally 80 and is now 95. There has been a concurrent downward shift in the SMR for "all malignancies," which is now 104 compared with 110 in the previous report. In the current study the SMR's for malignancies of various sites are also lower than in the 1974 and 1975 reports. The SMR for gastrointestinal tract tumors dropped from 94 to 75 in successive reports (these included 5 deaths from hepatic angiosarcoma); that for respiratory tract cancer (uncorrected for smoking) dropped from 112 to 107; and that for cancer of other and unspecified sites from 155 to 147. There is, nevertheless, still some support for the hypothesis that vinyl chloride may increase the incidence of cancer slightly in sites other than the liver. The principal evidence for this is the observation that the incidence of lung cancer and miscellaneous cancers appears to be higher in individuals with higher maximum exposures GTR37 and those with longer exposure periods. Brain tumors were found to be in excess, 12 observed vs. 5.9 expected ( significant at the 0.05 level ) but the incidence was not related to either duration of exposure or to intensity of exposure to VCM. This population should be studied again within the next 5 years. Since the time of observation after first exposures will be longer, and more deaths will be available for analysis, it is possible that some of the questions about cancer in sites other than the liver may be resolved. GTR38 Table 1 Distribution of Vinyl Chloride Plants Studied u., D-rtfHnrt and Numbers of Workers Pmdur.t or Products Polyvinyl chloride only Vinyl chloride monomer only PVC and VCM Copolymers, resins, with or without PVC and VCM TOTALS Number of Plants 18 11 3 5 37 Number of Workers 6,848 1,214 935 1,176 10,173 Number Traced 6,468 1,177 910 1,122 9,677 GTR 39 25 Table 2 Distribution of Vinyl Chloride Plants and Vinyl Chloride Workers by Census Regions and Geographic Divisions Region Geographic Division Percent of U.S. male Population (1970) Number of Plants in Study All regions 100.0 37 Northeast New England Middle Atlantic North Central East North Central West North Central South South Atlantic East South Central West South Central West Mountain Pacific 23.8 5.8 18.0 27.9 19.8 8.0 30.9 15.1 6.3 9.5 17.4 4.1 13.2 8 2 6 6 6 - 22 5 4 13 1 - 1 Number of Workers in Study 10,173 1,619 467 1,152 1,872 1,872 -- 6,589 1,735 2,868 1,986 93 -- 93 Number Traced 9,677 1,550 453 1,097 1,817 1,817 6,218 1,620 2,655 1,943 92 -- 92 GTR 40 Table 3 Follow-up Total Number 10,173 9,677 (95.1%) Alive 8,970 (92.7%) Dead 707 (7.3%) Death Certificate 669 (94.6%) No Death Certificate 38 (5.4%) 27 Traced 496 - .9%) GTR41