Document 2qLkQmY9knazyJK9DdkXznm36

1`IVUL U MORTALITY STUDIES Op EMPLOYEES EXPOSED TO VINYL CHLORIDE INTRODUCTION 18/7 36 -<o 6 l Ateur Pb&o ; ?ouj2 co c r3 This report examines the mortality experience of workers occupationally exposed to vinyl chloride at two locations of the Company, One location is designated Unit A, and the other Unit B. Because of considerable differences in the exposure levels be tween the two unitsj the results of the two studies should not be considered as directly additive. The objectives of the studies were twofold. The first objective was to re view the to-date mortality experience of employees in the populations of concern. The second, more long-range objective, was to establish two cohorts of employees who were exposed to vinyl chloride so that subsequent followup would be simplified. This report does not include a medical interpretation of the significance of the findings, but does include a description of the statistical methodology. a i Pursuant R&S 008966 STUDY OF UNIT A .uo/ METHODOLOGY Selection of the Population , Lunipanj i,r.L,v-'u3y3 SlH) westeJrLn District noff NNeeww YYoorrkk The exposed population included all employees of the Saran Department with the exception of salaried women personnel. The interval covered by the study was from 1949, when production first began, through 1963. January personnel lists for each of the years were examined to identify inscope employees. Through this mechanism, a total of 167 men were identified. Because the procedure for identifying employees in the exposed population used only January lists, a few individuals with less than one year of exposure might not be included in the study. However, virtually all employees with several years of expo sure would have been identified. No mortality followup of released employees other than retirees was undertaken. Recent industrial hygiene data (1972) have indicated that T.U.A. exposure levels to vinyl chloride for all jobs within the V^V2 area are well below 50 ppm. The exposure patterns were characterized as involving very low background levels with, occasional short term excursions to higher levels Ce-g*> over 500 ppm). A number of other chlorinated hydrocarbons were present in the plant atmosphere, including ethylene dichloride. Discussions with personnel familiar with past operations did not indicate that prior exposure levels differed greatly from recent levels. It was felt that lab assistants who collected samples from the production streams might have experienced the highest vinyl chloride exposures. Some high exposures to ethylene dichloride may have been experienced in the past years. In the analyses, exposure was quantified only in terms of years on the job within the department. No attempt was made to distinguish between different job classifica tions within the department. The employment and vital status of the exposed population as of January, 1973 was as follows: Employment and Vital Status Group Total Group <1 Yr. Exposure 1-6 Years Exposure 6+ Years Exposure Total Group 167 17 72 78 Still Working For Company 74 4 17 53 Retired Transferred Releases Other Than Retirees Deceased 10 7 66 10 05 5 0 2' ',"iari3i Produced Puryani - i, - Case fjo. 80-4837 11 - , L.n 44 11 04.CI/.O333SO4---------- 1 Western District!,t New York 4 Sources of Mortality Data and Comparison Population 71 ft (/> o o 00 d The mortality analysis is based on copies of death certificates received by th<= Company Group Insurance Department as proof of death. A cohort of 4,100 hourly em ployees of the location followed between 1954 and 1973 served as a control population. Mortality rates by age group and year of death were multiplied by the appropriate years at risk in the exposure group to provide the expected number of deaths. Since R&S 008968 -3the Company mortality rates for total malignant neoplasms closely paralleled the corresponding area white male mortality rates, these rates were used in computing the expected number of deaths due to malignant neoplasms. RESULTS The observed and expected deaths by duration of exposure and interval since initial exposure are shown in Table 1. The frequencies are too small for statistical tests of significance to be meaningful. A brief summary of the exposure history for each decedent is shown below. Cause of Death 1) Cancer of lip with metastases to lung and neck. Died 9/66. 2) Alveolar Cell Carcinoma. Died 11/71. 3) Carcinoma Brain and Lungs. Died 12/58. 4) Malignant Mediastinal Tumor Unclassified With Generalized Metastases. Died 1/63. 5) Ischemic Heart Disease. Died 6/71. 6) Abscess Left Frontal Lobe. Died 3/58. 7) Acute Myocardial Infarction. Died 2/65. 8) Accidental Drowning. Died 5/61. 9) Auto Accident. Died 7/58. 10) Unknown. Died 9/50. Department Work History Janitor 8/62-9/66 ij Operator 4/56-9/59 ^ Lab Assistant 9/59-5/67 I ^ " Operator & Shift Foreman- ^ __ 10/49-12/58 I Operator 1/62-1/63 | R&D Engineer 9/48-10/49 Welder 5/52-2/53 Operator 9/51-2/65 Operator 3/52-5/61 Clerk 10/50-3/51 Clerk 9/48-9/50 i-'i educed Pursuant , 'F-io, 904337 -. t.i. v-~:vtL-ai Company I.;. a4.CV.Q393 S(H) Western District of New York -4- STUDY OF UNIT B METHODOLOGY Selection of the Population With the assistance of Industrial Hygiene, a number of job classifications within several departments were identified as appropriate for study. These jobs were chosen because they involved more than minimal exposure to vinyl chloride. We attempted to select jobs with T.W.A. concentrations of at least 50 ppm. In a number of instances, where measurement data were not available, decisions were made subjectively. Con current exposure to vinyl and vinylidene chloride did not rule out a job classifica tion. However, if the exposure primarily involved vinylidene chloride, the job was not included. The list of selected jobs is shown in Table 2. In the analysis, exposure was quantified only in terms of years on the job prior to 1960. No attempt was made to estimate individual dosage levels from the industrial hygiene data which were available. One hundred eighty-seven men were identified who were assigned to at least one of the job classifications listed in Table 2. These men were traced by reviewing personnel lists over the period January 1942 to January 1955. The status of the exposed population as of November 1972 was as follows. R&S 008969 <1 Yr. Exposure 1-6 Yrs. Exposure 6+ Yrs. Exposure Still working for company Retired Releases other than retirees Deceased 16 5 23 3 50 39 6 14 13 2 6 10 __ i i fi^s ' Conor,., taife Uj. 90-4037 Calcasieu Parish, LA Smith v. The Dow Chemical Company Case No. 94-CV-0393 S(H) Western District of New York Pnrcn.mt -5- Because the procedure for identifying employees in the exposed population used only January lists, a number of individuals with less than one year of exposure might not be included in the study. However, virtually all employees with several years of exposure would have been identified. No mortality followup of released employees other than retirees was undertaken. Source of Mortality Data The mortality analysis is based on copies of death certificates received by the Company Group Insurance Department as proof of death. A cohort of 6500 Dow hourly workers, followed between 1954 and 1969, has served as a control population for our mortality studies. Mortality rates by age and cause of death observed for this cohort of employees, when multiplied by the years at risk in the exposure group, provide the number of expected deaths in the exposed population. The cohort does represent a cross-section of Dow hourly employees. However, it should be recognized that em ployees in a particular exposed population may be subject to selection biases which are not present in the control population. Thus, significant differences between ex posed individuals and controls cannot be automatically attributed to the exposure. RESULTS The observed and expected deaths by duration of exposure and interval since ini tial exposure are shown in Tables 3 and 4. Table 3 relates to total deaths and Table 4 relates to deaths due to malignant neoplasms. Cohort 1 refers to employees who first worked in the exposure area prior to 1950. Cohort 2 refers'-tO'itrho.S'erifgmEloitees rwho !a ^r-'ectiv- a-,af ! Prod"cedPursuant first worked in the area between 1950 and 1955. ob tained. Overall, tjie`folTowingfj^e^u^t^j^ere . '' '-J' i.A ifbJtejDuw Chs-'ra! Western District of New Vo* Cause of DeathObservedExpected R&S 008970 All Causes 19 18.5 All Malignant Neoplasms Respiratory Malignancies 8 4.4 PS .08 17 R&S 008971 Almost a twofold difference was found between observed and expected deaths due to malignant neoplasms. This difference was not, however, significant at the .05 level. If there were a relationship between malignant neoplasms and exposure to vinyl chloride, the peak risk for employees in the higher exposure groups would likely extend from 15 to 40 years after initial exposure. Five malignancies were observed during this period, as opposed to an expected number of 2.3. Again, while the mortality ratio was 2.2, the probability of observing these results under the hypothesis of no difference is approximately .08. A brief summary of the exposure history for the eight individuals who died from malignancies is shown below. Cause of Death Work History (1) Widespread metastatic carcinoma - Age 54, 25 years after first VC1 exposure Saran Polymer 27 years; 3 yrs. exposure to >50 ppm VC1 (2) Adeno carcinoma of colon, carcinomatosis Age 56, 25 years after first VC1 exposure Saran Polymer 26 years; Carbon tetrachloride 8 years; 7 yrs. exposure to >50 ppm VC1 (3) Squamous cell carcinoma primary site undeter mined; generalized metastases undiffer entiated - Age 61, 28 years after first VC1 exposure Saran Polymer 24 years; 9 yrs. exposure to > 50 ppm VC1 (4) Carcinoma of lung Age 54, 17 years after first VC1 exposure Saran Polymer 17 years; Cal Mag 2 years; 3 yrs. exposure to >50 ppm VCl (5) Leukemia, acute granu locytic - Age 45, 20 years after first VC1 exposure Saran Polymer 10 years; Ethylbenzene 10 years; Brom Indigo 2 years; 7 yrs. exposure to >50 ppm VCl Smoking History Had formerly smoked 40 cigarettes per day for 36 years Unknown Unknown ..0 4837 d Pursua - -Company 04-CV-03S3 S(HJ Western District of New York Unknown 1 cigar/day for 20 years -7- Cause of Death Work History Smoking History (6) Carcinoma stomach meta static to vertebrae, retroperitoneal lymph nodes and lungs Age 54, 12 years after first VC1 exposure Saran Polymer 13 years; Wrought Prod. 3 years; Electro-Chem 1-1/2 years; 1 year exposure to > 50 ppm VC1 Unknown (7) Carcinoma prostate with metastases - Age 60, 11 years after first VC1 exposure Vinyl Chloride Monomer 7 years; Tetrachloroethylene 11 years; Anhydrous HC1 4 years; 7 years exposure to > 50 ppm VC1 Unknown (8) Carcinoma of brain Age 61, 4 years after first VC1 exposure Saran VjV2 4 years; Wells 4 years; Graphite 1-1/2 years; Ethylene Dichloride 1 year; Acetanilide 1 year; Lt. Stabilizer 2 years; 2 years exposure to > 50 ppm VC1 conf-uen-iai Male,,! Produced Pursuant Casa No. 00-4837 tase Wo. 94-CV-OJtio S(H) Western District ot New York R&S 008972 SUMMARY These studies found no significant statistical differences (P*t.05) between the mortality experience of employees exposed to vinyl chloride and the corresponding control populations of Dow employees. However, in dealing with small numbers, only large relative differences can be detected statistically. There is no comfort in the approximate twofold increase in malignancies, even though it could well be a chance occurrence. Two future courses of action could be recommended. First of all, updating these studies on a yearly basis would be a relatively simple undertaking. Secondly, com bining these results with the findings of other companies could prove invaluable in two ways: the size of the study could be increased, and, selection biases could be better controlled in a multi-company study. Table 1. Observed and Expected Deaths by Duration of Exposure and Years since First Exposure - All Causes and Total Malignant Neoplasms * A" Duration of Exposure In Years Total Group 1 Year 1-6 Years 6+ Years Interval Since First Exposure <15 Years 15+ Years <15 Years15+ Years <15 Years 15+ Years <15 Years 15+ Years * ' Number of Deaths All Causes Observed Expected 8 4.8 2 4.7 2 .3 0 .1 3 2.1 1 1.4 3 2.4 1 3.2 Duration of Exposure In Years Total Group 1 Year 1-6 Years 6+ Years Interval Since First Exposure <15 Years 15+ Years <15 Years 15+ Years <15 Years 15+ Years <15 Years 15+ Years Number of Deaths Malignant Neoplasms Observed Expected 3 1.1 1 1.1 0 .1 0 .0 2 .5 0 .4 1 .5 1 .7 R&S 008973 Dow Chemical Confidential To Protective Order M nteiia! Produced Pursuant Ross y^Cc.nnco, H., Csie Me 90-4837 CaiCtjfSL' /c.'isii,!\ Simli y, tfm Cow q ompany Case ,"Jo. S4-CV-03.93 S(HJ Western District of New York R&S 008974 Table 2. Departments and Job Classifications To Be Included In Study. nuucc Saran Poly Semi Plant Foreman Polymer Operator (or equivalent) Asst. Polymer Operator (or equivalent) Wheel Filter Operator (or equivalent) 1947 - 1955 1946 - 1955 1946 - 1955 1946 - 1955 Saran Polymer Department (Or Equivalent) Foreman, Shift Foreman, Subforeman* 1941 - 1950 Polymer Operator (or equivalent) 1941 - 1955 Drier Operator (or equivalent) 1941 - 1955 Assistant Operator 1944 - 1955 Tank Car Unloader (or equivalent) 1951 - 1955 Asst. Polymer Operator 1952 - 1955 Asst. Drier Operator 1552 - 1955 Plant Mechanic 1941 - 1955 Vinyl Chloride Department Foreman P"" 1946 - 1954 u,,,oiJuceu8ursu Ka. 90-4837 Vinyl Chloride Operator Saran V1V2 Plant** 1946 754 CV03S3 S(H) Eastern District of New York Shift Foreman 1952 - 1955 Polymer Operator 1952 - 1955 Coagulator Tank Wheel Operator (or Equiv.) 1952 - 1955 Drier Operator 1952 - 1955 *After 1950, personnel lists for Saran Polymer and Saran Color and Blending were combined. Thus, it was not possible to distinguish which operations the foremen were connected with. The assumption was made that foremen who were known to supervise the polymerization operations prior to 1950 continued in that section after 1950. **To the extent chat employees in Saran V1V2 had previously worked in Soluble Saran, this exposure experience will be considered additive. However, men who worked only in Soluble Saran would not be included in the study. Table 3. Observed and Expected Deaths By Duration of Exposure Years Since First Exposure, and Cohort--All Causes. rWu'T'- Duration of Exposure In Years Interval Since First Exposure <1 Year <15 Years 15 - 24 Yrs. 25 - 32 Yrs. Total Number of Deaths--All Causes Cohort 1 Cohort 2 Observed Expected Observed Expected 1 1.0 2 .5 - 1.3 -- .1 - .2 *-- -- 1 2.5 2 .6 R&S 008975 <15 Years 1-6 Yrs. 15 - 24 Yrs. 25 - 32 Yrs. Total f <15 Years 6+ Yrs. 15 - 24 Yrs. 25 - 32 Yrs. Total Duration of Exposure In Years -- 1.1 1 .9 1 .2 2 2.2 2 2.6 2 1.9 -- -- 4 4.5 1 1 3 5 Interval Since First Exposure 1.2 1 1.7 3.1 4 1.8 .9 -- -- 5.2 5 r- 3.5 , . . rouucsd . j. bJ-4837 Number^of. T)pat-hg/--:nil':ai Company A13L'aCatis!ei^'^-3333 S(H) New York Observed Expected <1 Year 1-6 Years 6+ Years <15 Years 15+ Years <15 Years 15+ Years <15 Years 15+ Years 3 1.5 0 1.6 2 3.7 4 3.0 2 2.9 8 5.8 Table 4. Observed and Expected Deaths By Duration of Exposure, Years Since First Exposure, and Cohort--Malignant Neoplasms. R&S 008976 Duration of Exposure In Years <1 Year 1-6 Years 6+ Years Interval Since First Exposure <15 Yrs. 15+ Yrs. <15 Yrs. 15+ Yrs. < 15 Yrs. 15+ Yrs. Number of Deaths Due To Malignant Neoplasms Both Cohorts Observed Expected 0 .3 .3 2 .7 2 .8 .7 uvrt Chemical Confide 'tial ijerisj Produced Pursuant to Pretence Order CfiT ; h:. ihiia No. 00-4037---- lli i /; v. The Dow Chemicai Company Case No. &4-CV-0393 S(H) Western District of New York