Document zod2n4NXMJNab3kbo2LZ7aRE7

yl'umctt Health R&s 041190 Medical Surveillance of Yinyl Chloride Workers R. R. COOK Presented at the public hearing on vinyl chloride. Occupational Safety and Health Administration, U.S. Department ofLabor, Washington, D.C.. June 25.1974 My name is Dr. Ralph Cook. 1 am a physician in the Midland Division* of- Dow Chemical U.S.A. I obtained my medical decree from Wayne State University. I received residency training in Occupa tional Medicine and a master's degree in public health from the University of Michigan. I have completed requirements for certification in occupa tional medicine and have taken ray board examina tion. While in the military. I worked in the toxicol ogy laboratory of the Army Environmental Hygiene Agency, Edgewood Arsenal. Maryland. At the present time I am involved in a study for the Division of Medical Sciences. National Research Council, under contract to the Environmental Pro tection Agency. I came to Dow two years ago and am currently in charge of the division's Health Inventory Program. Today. I would like to report an analysis of selected health surveillance data on 535 chemical workers who had industrial exposures to vinyl chloride. The details of their exposures have al ready been reviewed by Mr. Daniel.*". In the clinical parameters considered in our study, there was nothing of statistical significance below vinyl chloride levels of 200 ppm. Above this level only diastolic blood pressure showed a statis tically significant deviation. We have-provided periodic employee health ex aminations to a varying degree for over 20 years. I refer you ro the American Industrial Hygiene Asso ciation Journal (33, 19 (1972)) in which C. G. Kramer and J. E. Mutchler of The Dow Chemical Company correlated clinical and environmental measurements for workers exposed to vinyl chlo ride prior to 1967. Their findings "suggest that repeated exposure to vinyl chloride at TWA levels of 300 ppm or above for a working lifetime together with very low levels of vinylidene chloride may result in slight changes in certain physiological and clinical laboratory parameters. The possibility of some impairments in liver function tests must be considered, even though no overt clinical disease was evident in any of the individuals studied.*' Since 1967 we have utilized multiphasic health screening techniques to evaluate our employees' health status. We call this our Health Inventory Program. The employee is evaluated in our Health Screening Center, which, during the year, is moved to various locations around the plant. This program has evolved somewhat since its inception to the "Since rhi* p.ip<tr w:vs presented. the MidE-ind Division hos been remimeJ the Michicnrt Division. *'R. L. D.inict. inJuiln;ii Aycieni't. Texas Division. Dow Chemical U.S.A.. Freeport. Texas. R&S 04119^ int where It now Includes a history and the tasuremem of over 40 separate anfbropomorphi[ and biochemical variables. It is an extraction of :n from this program that I wish to discuss today. A synopsis of the parameters that are evaluated our current program is covered by Table l. lich is in the record. The medical history includes, among other ngs. information on hospitalizations, numbness the hands, respiratory difficulties, liver probns. alcohol ingestion, anemia, and current medi:ions. We do a detailed smoking history. We juire into the number of stillboms. miscarriages. J birth defects. Dur evaluation includes chest x-ray, electrocar>gram. pulmonary functions, hematology, uritysis. and a variety of blood chemistries, includ; lactic dehydrogenase (LDH), serum glutamic alacetic transaminase (SGOT), total bilirubin, aline phosphatase. BUN, uric acid, creatinine, cium, total protein, albumin, and cholesterol. The results are compiled, and reviewed by a vsician. Based upon the physician's evaluation, lowup studies are instituted. We recommend that each employee request that forward the results of his periodic health inveny evaluation to his personal physician. We stress jponsible followup and continuity of medical e. n this study, the population of interest was lined to be production employees at one manicturing location who worked for at least one year :ween 1942 and January 1972 in areas with potenI vinyl chloride exposure. It was further defined include only those individuals who were employ; of the Midland Division between February 1967 J March 1974. the inclusive period of the Health /entory Program. Based upon a review of industrial hygiene data, eh individual was assigned to one of four exsure groups: high, intermediate, low and un fined. The categories were based on estimated le-weighced average concentrations for an eightur day (TWA). The high level was defined as posures above 200 ppm for at least one month's ration: the intermediate level was 25 to 200 ppm: d the losv level as less than 25 ppm. For 81 iividuals insufficient industrial hygiene data was ailable to accurately estimate their exposures, d they were placed in the undefined group. A bjective evaluation by industrial hygienists indi ted thac the exposures in the undefined group :re. for the most pan. In the low to intermediate age. In placement of Individuals in particular exposure groups, precedence was given first to a history of high exposure; then intermediate exposure: next undefined exposure: and. finally. low exposure. Table 2. also in the record, gives a breakdown as to the number of employees in each group and the number who voluntarily participated in the Health Inventory Program. The participation rate among the various exposure groups was about 80% . As of March 1974. we were, in the final stages of our fourth cycle through the plant. Because of major revisions in the Health Inventory Program in 1970. data before and after this dace have been analyzed separately. This conveniently breaks our analysis down into a study of the first two cycles and the last two. In the first two cycles, February 1967 to Decem ber 1970. 10 clinical parameters were evaluated. Two of them, serum protein and hemoglobin, had insufficient data and were discarded. Data of the remaining eight were analyzed: FVC (forced vital capacity), FEVi (forced expiratory volume--one second), systolic blood pressure, diastolic blood pressure, white blood count, total bilirubin, SGPT (serum glutamic pyruvic transminase) and alkaline phosphatase. The mean value of each ot these tests was determined for the exposure group and for a control group of matched pairs. The control group was matched for sex. age. smoking history, month of exam, and, where posible. master number. Our master numbers are sequential based upon date of hire. Master numbers of similar magnitude indicate similar lengths of employment. The only statis tically significant deviation (P <-05) was for a decreased diastolic blood pressure on the high exposure group. All other tests in all exposure groups, including undefined exposure, showed no statistically significant differences. What's the clini cal significance of the finding? I don't know. A number of questions from the history have also been analyzed: shortness of breath; chronic cough; yellowjaundice; stomach, liver, and intestinal trou ble; numbness in hands and feet: cancer or malig nant growth; anemia or blood problems. No signifi cant differences were noted between the exposure group and the matched-pair control group. Similar analyses were made on selected labora tory data and questions of the last two health inventories, January 1971 to March 1974. Tables 3 and 4 zive a list of parameters that were considered for this report. The questions were similar to those asked pre viously. The laboratory studies included pulmonary functions, hemoglobin, white blood count, total bilirubin. SGOT (serum glutamic oxalacetic trans aminase), LDH {lactic dehydrogenase), total pro tein, protein albumin, and protein globulin. During this period three separate techniques for alkaline phosphatase, involving three separate normal ranges, were utilized by our consulting laboratory. For this reason a statistical analysis of the results of this study was not made. Review of the individual results revealed nothing of clinical concern. In all other parameters studied nothing of statistical sig nificance was found. We have studied various parameters of our em ployees* health for over 20 years, including a num ber of those suggested by the proposed standard. We plan to continue this medical surveillance and will continue incorporating new techniques as they are developed and as they apply to our operation -- techniques such as automated multiphasic testing, computerized medical records, enzymatic studies, analysis of metabolic end products, chromosome studies, and exfoliative cytology. This report is a summary of our findings of past studies. Above 200 ppm. some deviations were noted in various health parameters; below 200 ppm nothing of statistical significance has been ob served. A group trom the Institute of Environmental and Industrial Health. University of Michigan, has made an extensive study of over 5000 employees of 32 plants involved in various phases of vinyl chlo ride and polyvinyl chloride manufacturing. Their findings can found in a series of articles entitled "Occupational Acroosteolysis** in the Archives of Environmental Health (22. 6l(January 1971)). Our Midland location was one of the plants studied. They found no acroosteolysis in our work force. As has been mentioned in previous testimony, a group of health researchers from Mt. Sinai New York Medical Center has also recently studied a group of our Midland location employees. In Dr. Selikoff s preliminary evaluation he brings up some interesting clinical observations. Dr. Selikoff stated yesterday his evaluation is in complete and further analysis of his data is needed. As Dow has indicated to Dr. Selikoff several times, we look forward to working with him in developing meaningful dose response information -- to combin ing our 20-plus years of industrial hygiene data, our 20-plus years of medical surveillance data -- with his expertise in occupational medicine. Our ulti mate concern is the health of our employees. Table 1 - Health Inventory R&S 041192 Identification Work History Family History Smoking History Family Physician Medical History Medications X-Ray Electrocardiogram Pulmonary Functions Vision Hearing Intraocular Tensions Height Weight Blood Pressure Hematology Urinalysis Chemistries: BUN Glucose Uric Acid Creatinine Calcium Bilirubin Protein Total Albumin SGOT Alkaline Phosphatase L0H Cholesterol able 2 --'Employee Participation in Health Inventory Program by Exposure Croup ------ ---------- r. - -- ' V- Total t~ r"s_. - .---------- **'**- . High - Intermediate- Low Employees Of 1/68 335 113 63 73 Employees Of 1/74 27S 102 54 63 Employees With One Or More Exams 2/67 to 3/74 277 93 55 64 Employees With One Or More Exams 2/57 To 12/70 233 83 44 54 Employees With One Or More Exams 1/71 To 3/74 212 72 44 5 Undefined i 81 57 .64 58 47 S9 able 3 -- Parameters Studied January 1972 to Table 4 -- Health Inventory Questions Cycles Tarch 1974 Three and Four R&S 041193 SCOT (Serum Glutamic Oxalacetic Transaminase) ALKALINE PHOSPHATASE LOH (Lactic Dehydrogenase) TOTAL PROTEIN ALaUMlN GLOBULIN TOTAL BILIRUBIN DIASTOLIC BLOOD PRESSURE SYSTOLIC BLOOD PRESSURE P/C (Forced Vital Capacity) FEV (Forced Expiratory Volume -- One Second) HEMOGLOBIN SHORTNESS OF 5REATH COUGH LASTING OVER THREE MONTHS NUMBNESS IN HANDS OR FEET YELLOW JAUNDICE LIVER TROUBLE ANEMIA OR BLOOO PROBLEMS CANCER OR MALIGNANT GROWTH r