Document N2jN08w6nzXQv0nom36Ew4DdE

Mortality Among Workers Employed in Petroleum Refining and Petrochemical Plants 1- L Thomas, M.S.; Pierre Decoufle, Sc.D.; and Rafael Moure-Eraso, M.S. The cause-specific mortality experience of 3,705 members of the Oil, Chemical and Atomic Workers International Union was examined to determine if there were unusualpatterns of fatal disease that may be indicative of hazardousagents in the work environment. Deaths among active Union members that were reported by locals in Tatas between 1947 and 1977 were identified through membership records, and proportionate mortality was JMlyzed in several broad industrial categories. PMRs for racers of the liver and biliay passages, pancreas. lung and skin were elevated among refinery and petrochemical Plant workers; however, risks did not increase with length of membership. Increasedrelative frequencies of stomach cancer, cancer of the brain, leukemia and multiple mveloma were confined to white males in the same ategory who had been Union members for 10 or more Yean. Excess deaths from stomach cancer and brain cancer were found among white male members employed at one s W i f k oil refinery and petrochemical plant. Observed numbers of deaths from cancer of the stomach were than expectedamong whites and nonwhites, and an elevated PMR for lung cancer among nonwhites was !mdat an additional plant. Findings suggest that workers `n this industry may be at increased risk of certain cancers and indicate areas for further investigation. studies have indicated the need for further ealuatlon of cancer risks among persons employed in Petroleum refineries and petrochemical plants In a r e cent study of cancer mortality by county, hlgh rates of F mthe Occupational Studies Section Environmental Epidemiology NatlondlCancer institute 3C07 Landow Building, Bethesda MD 20205 k m f kIS affiliated with the School of Health Related Professions.Univer- AflzOm Tucson Ariz and Mr Moure-Erasois with the Health and Sate CQdOOffwe. 011. Chemical and Atomic Workers international Union Denver cancers of the lung, nasal cavity and sinuses, and skin were found among male residents of counties where the petroleum industry is heavily concentrated.' Early studies indicated increased risk of scrotal cancer among wax pressmen in a refinery' and cancer of the larynx and nasal sinuses among workers engaged in the manufacture of isopropyl a l ~ o h o l .A~lthough no increased cancer risks have been found in more recent studies of US. refinery workers,' a Canadian study has reported elevated risks of esophageal, stomach, and lung cancer among workers exposed to crude petroleum and its products.' The opportunity to evaluate cancer risks among a large group of workers employed in petroleum refineries, petrochemical plants and related industries arose when officials of the oil, Chemical, and Atomic Workers Inter- national Union (OCAW) invited the National Cancer Institute to review data sources within the Union that might be useful for a epidemiologic study. The present report examines the cause-specific mortality experience of Union members to determine if there was an unusual pattern indicative of hazardous agents in the work envirorr ment. The purpose of this study is to point out areas for further investigation. Materials and Methods In considering what kind of study design might be possible, a retrospective cohort study was deemed not feasible because of limitations in the Union's recordkeeping system. Since records of deaths among active Union members are maintained by the Membership Department, we decided to examine the relative frequency of specific causes of death as a preliminan/ means of obtaining an estimate of site-specific cancer risks in various broad industrial categories within the petroleum refining, petrochemical, and related industries. Because of the heavy concentration of the petroleum industry in the state of Texas, and the large OCAW Of OccupationalMedicine/Vol. 22, No. 21February 1980 97 -Table 6. Mortality for Selected Cancer SRes in White Male Texas OCAW Members in Category 2 by Length of Union Membership. 1Revision, ICD) Live1r and biliary passages 1 ft55. 156) Length of Membership < (N 10= Y5_e7ar8s) ~ . (.1N..0+= Y.e.ars~. ~ 1144) I 0 9 IEt PMR E$ PCMR E TPMR 0' E t PMR E$ PCMR E T 4 5 2 4 208 2 6 190 2 7 184 7 4 6 152 6 8 103 5 7 122 i ~ Pancreas (157) 15 4 4 3 3 8 1 5 3 2817 5 2 2 8 9 7 14 1 2 5 1 1 2 1 6 7 0 8 4 1 2 4 1 1 3 Lung (162, 163) Skin (172. 173) 435 21 7 1 6 1 1 24 3 1 4 4 1 25 9 1 35 95 74 3 1 2 8 1 91 1 1 0 4 76 6 1 241 2 6 2 3 2561 2 7 223 3 4 179 8 4 9 165 6 2 129 6 3 126 1 '0 = Observed deaths t E = Expected deaths based on proportionate mortality for U.S. white males $E = Expected deaths based on proportionate cancer mortality for U.S.white males E = Expected deaths based on proportionate mortality for Texas white males (Statistically significant at the 0.05 level I relative frequencies of specific causes of death, excesses pected for nonwhites. Further analyses of cancer risk a i for one or more causes will automatically force others to limited to decedents employed in petroleum r e f i m be in deficit, In addition, whenever multiple comparisons and petrochemical plants (Category 2). 4 are made, a certain number of differences will be If occupational exposure contributes to cancer risk,i statistically significant based on chance alone. Despite its generally expect risk to increase with increasing dura limitations, a PMR analysis is useful as a preliminary, of exposure, or, in this case, with length of member! hypothesis-generating step. Specific cancer sites that were associated with incre; relative frequencies in Category 2 were examined wl Results respect t o length of membership. Not all cancer sites' Distribution of study subjects by industrial category is elevated PMRs in the petroleum refinery 4 shown in Table 1. Most of the decedents were classified petrochemical category show a positive gradient. TabG into Category 2. Only 55 decedents worked for com- shows cancer sites for which risk among members in d panies that could not be classified. category does not increase with leogth of member4 Since the study group is comprised entirely of workers The elevated PMR for cancer of the pancreas is confini who were active Union members at the time of death, less to members initiated less than IO years prior t o de4 than 1% were age 65 or older; however, over half of the Observed numbers of deaths from cancers of the lid 3,105 decedents were 50 or older (Table 2). lung, and skin are greater than expected regardless.: Table 3 indicates that 62% of the whites and 57% of length of time between initiation and death. PCMRs c d the nonwhites died 10 or more years after initiation into puted for each of these sites show essentially the san <the Union. A substantial number (> 25%) were members pattern for the 10 year membership group; how& for 20 or more years prior to death. ratios are smaller for decedents who were members for' PMRs for maior causes of death are shown in Table 4, or more years. Results using Texas white males as a ca by race, for each industrial category that had at least 100 parison group vary little from the expected values ba deaths. Among whites, the relative frequency of cancer on the total US. males for each site except skin. TPM deaths is elevated only in Category 2. Ratios for heart for skin cancer are much lower than PMRs but rer disease are elevated in both racial groups and in each in- elevated. 3 dustrial category. Observed numbers of deaths from Table 7 shows cancer sites for which risk increaseswi respiratory and digestive disease are lower than expected length of membership for white males in the petroleu in each category and exceptionally low among whites in refinery and petrochemical plant category. An increas Category 4. An increased relative frequency of motor relative frequency of stomach cancer is confined vehicle accidents is seen among whites in Categories 1 members who joined the Union 20 or more years prior and 3 and among nonwhites. Non-motor vehicle acciden- death. There were four deaths from multiple myeloma tal deaths are elevated in each category except 3. the same length-of-membership group and only 1 Site-specific cancer mortality is shown in Table 5 for expected Deaths from leukemia and from cancer each of the industrial categories in which there were at brain and central nervous system seem to cluster least 100 total deaths. Most interesting are results for the males who were Union members for 10 or more petroleum refinery and petrochemical plant category Although an increased relative frequency of (Category 2). Among whites, observed numbers of deaths cancer deaths is not present in the total group, there are significantly greater than expected for cancers of the significant excess of deaths among members who wer digestive and respiratory systems, skin, and brain. A non- itiated at least 20 years prior to death, with seven de significant excess of respiratory cancer deaths appears in observed and 3 3 expected Expected numbers of de the crude oil and gas extraction category (Category 1).No based on proportionate cancer mortality are higher other site/category combination is associated with those based on proportionate mortality, however, unusual mortality, although the numbers of deaths are same trends are present small in many instances. Observed numbers of deaths Table 8 shows cancer sites contributing to the exc from digestive and respiratory cancer are greater than ex- shown in Table 5 for nonwhite males Increased rela 100 Mortality Among Workers in Petroleum Refining and Petrochemical PlanWThomas Decoufle. and Moure-E I N A N W 4-W :I I -0 I Wm Lr o, A- b b Nm Nw AWPa- 0roUl- 0 U m m w 0, 0 - . .. -W0 4 - N WV A -4 N PW PuPO 0 0 ov m mvl N 0 P O-VI -0 I I I I Oc o4N - WW U U NWP A 2ww U A -U W N4 Q, 2% d w- N e mti O N O U l Q) O N- - - -- 0 o N PO -e - 2Oo V~I WoN m0N h Nw u- m Wo - k +t i+ -. N W 0) N U 0 - 0) orAoN- - -co o m P V I U 00 w P I 5 l wr o ww Journal of Occupational Medicine/Vol. 22, No. 2/February 1980 L 99 -fable 6. Mortality tor Selected Cancer Sites in White Male Texas OCAW Members in Category 2 by Length of Union Membership. Sit8 (8th Revision, ICD) 1 Lsnqth of 1 mbsrship < 10 Years (N = 578) 0' E t PMR E+ PCMR E TPMR 10+ Years (N = 1144) Liver and biliary passages (155, 156) Pancreas (157) Lung (162. 163) Skin (172, 173) 5 2.4 2.08 2.6 1.90 2.7 1.84 7 4 6 1 5 2 6 8 1 0 3 5 7 15 4.4 3.387 5.3 2.817 5.2 2.891 14 1 2 5 1 1 2 1 6 7 0 8 4 1 2 4 35 21.7 1.611 24.3 1.441 25.9 1.35 95 74 3 1 281 91 1 1 04 76 6 6 2.3 2.561 2.7 2.23 3.4 1.79 8 4 9 1 6 5 6 2 1 2 9 6 3 122 113 1 241 126 '0 = Observed deaths t E = Expected deaths based on proportionate mortality tor U.S. white males $E = Expected deaths based on proportionate cancer mortality for U.S. white males E = Expected deaths based on proportionate mortality for Texas white males 1Statistically significant at the 0.05 level relative frequencies of specific causes of death, excesses pected for nonwhites Further analyses of cancer risks are for one or more causes will automatically force others to limited to decedents employed in petroleum refineries be in deficit. In addition, whenever multiple comparisons and petrochemical plants (Category 2). are made, a certain number of differences will be If occupational exposure contributes to cancer risk, we statistically significant based on chance alone. Despite its generally expect risk t o increase with increasing duration limitations, a PMR analysis is useful as a preliminary, of exposure, or, in this case, with length of membership. hypothesis-generating step. Specific cancer sites that were associated with increased relative frequencies in Category 2 were examined with Results respect to length of membership Not all cancer sites with Distribution of study subjects by industrial category is elevated PMRs in the petroleum refinery and shown in Table 1. Most of the decedents were classified petrochemical category show a positive gradient Ta into Category 2. Only 55 decedents worked for com- shows cancer sites for which risk among members IC !hi panies that could not be classified. category does not increase with length of membership. Since the study group is comprised entirely of workers The elevated PMR for cancer of the pancreas SI confined who were active Union members at the time of death, less t o members initiated less than 10 years prior to death than 1% were age 65 or older; however, over half of the Observed numbers of deaths from cancers of the liver, 3,105 decedents were 50 or older (Table 21. lung, and skin are greater than expected regardless of Table 3 indicates that 62% of the whites and 57% of length of time between initiation and death PCMRs corn the nonwhites died 10 or more years after initiation into puted for each of these sites show essentially the same <the Union. A substantial number 0 25%) were members pattern for the 10 year membership group. however, for 20 or more years prior to death. ratios are smaller for decedents who were members for 10 PMRs for major causes of death are shown in Table 4, or more years Results using Texas white males as a corn by race, for each industrial category that had at least 100 parison group vary little from the expected va!ues based deaths. Among whites, the relative frequency of cancer on the total U S males for each site except skin TPMlZI deaths is elevated only in Category 2. Ratios for heart for skin cancer are much lower than PMRs but rema disease are elevated in both racial groups and in each in- elevated dustrial category. Observed numbers of deaths from Table 7 shows cancer sites for which risk increases respiratory and digestive disease are lower than expected length of membership for white males in the petrol in each category and exceptionally low among whites in refinery and petrochemical plant category An increa Category 4. An increased relative frequency of motor relative frequency of stomach cancer is confined to vehicle accidents is seen among whites in Categories 1 members who pined the Union 20 or more years prior to and 3 and among nonwhites. Non-motor vehicle acciden- death There were four deaths from multiple myeloma in tal deaths are elevated in each category except 3. the same length-of-membership group and only 1 3 were Site-specific cancer mortality is shown in Table 5 for expected Deaths from leukemia and from cancers of the each of the industrial categories in which there were at brain and central nervous system seem to cluster a m o q least 100 total deaths. Most interesting are results for the males who were Union members for 10 or more years. petroleum refinery and petrochemical plant category Although an increased relative frequency of k l d w (Category 2). Among whites, observed numbers of deaths cancer deaths is not present in the total group, there is a are significantly greater than expected for cancers of the significant excess of deaths among members who were iw digestive and respiratory systems, skin, and brain. A non- itiated at least 20 years prior to death, with seven significant excess of respiratory cancer deaths appears in observed and 3 3 expected Expected numbers of the crude oil and gas extraction category (Category 1).No based on proportionate cancer mortality are high other site/category combination is associated with those based on proportionate mortality, however, unusual mortality, although the numbers of deaths are same trends are present small in many instances. Observed numbers of deaths Table 8 shows cancer sites contributing to the excesseS from digestive and respiratory cancer are greater than ex- shown in Table 5 for nonwhite males Increased relative Z" 12100 Mortality Among Workers in Petroleum Refining and Petrochemical Plants/Thomas. Decoufle. and Moure-Era9 muencies of cancers of the stomach and lung are seen length-of-membership groups shown here. Results ,f the KMR analysis are not too different from those of he PMR analysis; however, the estimated risk for lung .ancer is reduced. In order to determine whether the increased risks of &fic cancers among OCAW members employed in erroleurn refineries and petrochemical plants were con- reed to employees of particular plants, mortality patterns .ere examined in five plants from which at least 100 kaths had been reported. Plant A is a large petroleum refinery with 421 deaths tmong whites and 54 deaths among nonwhites. Some jnion members employed at this plant are guards; +ever, most are production workers. The observed xrmber of stomach cancer deaths is significantly greater :han expected among whites who died 20 or more years liter joining the Union (Table 9). The excess of deaths -rom cancers of the brain and central nervous system is iimited to workers with at least 10 years of membership. 4rnong nonwhites there were one death from stomach 3ncer and no deaths from cancer of the brain. Plant B is a petroleum refinery and petrochemical plant that also produces sulfuric acid. Certificates were -=overed for 413 deaths reported by the Union local dur.ng the study period. Observed numbers of deaths for cancers of the stomach, skin, kidney, and leukemia are greater than expected for whites with 10 or more years of membership (Table 10).Significant excesses of stomach and lung cancer are present among nonwhites. Expected numbers of deaths were not calculated for nonwhites by length of membership because of the small numbers. Brain cancer was not excessive in either racial group. Significantly increased relative frequencies of brain (5 observed; 1.5 expected) and of lung cancer deaths (22 observed; 11.7 expected) were seen among 198 whites who worked at Plant C, which functions as a refinery and Products terminal. Although numbers were very small, we examined mortality patterns by length of membership md found that the brain cancers clustered among males *ho were members for less than 10 years (all of the dece h-16in this group with brain tumors were members for nine years) while the lung cancer excess was confined to with at least 10 years of membership. No excesses of specific cancers were seen among members whoworked in the other two plants that were examined separately. Dkussion The present study provides an example of the epidemi- ologic value of data collected routinely for administrative Purposes. As pointed out earlier, the primary use of this 4'- ef & d y is as a hypothesis-generating report. PMRs for some causes of death may appear higher than they should because of lack of information on members who retired or left the Union for other reasons. No conclusions can be drawn with respect to exposure to specific agents; however, categories of industrial prcl cesses and individual plants associated with higher than risks can be identified. In spite of limitations imposed by the "healthy worker effect" and the lack of ex- posure information, the finding that risks of stomach Journal Of Occupational Medicine/Vol. 22. No. 2lFebruary 1980 0 0 Y Y -u -me - -0 0 % Iw-we Nu w- 0 Iw 0) -mm - -NO)m 1 Oe uN roo, -0) 0 I2 -mP - -o e w I- h OW NU? ww IN N N ~ Na m -mol WON AN I?% W-l -A N Is -0Ym mW0Y -- ly2 WW whi c 15 -ma NU w o ( D (Dol -fv i ww ma 4 A lw o, 101 Sitl (Bth R e v i s i i , ICO) S l m c h (151) Lung (162,163) I < 10 Yean (N = 150) Length of MrmbmMp I IO+ Y#n (M = 259) 0' E t PMR E$ PCMR E TPMR 0' E t PMR E$ PCMR E TPYR -5 2.1 2.421 2.7 1.87 2.2 2.31 12 4.3 2.801 6.2 1.921 4.6 2.59l 7 3.8 1.82 4.7 1.48 4.8 1.46 19 14.1 1.35 16.6 1.14 12.3 1.55 '0 = Observed deaths t E = Expected deaths based on proportionate mortality for U.S. nonwhite males *E = Expected deaths based on proportlonate cancer mortality for U.S. nonwhite males E = Expected deaths based on proportionate mortality for Texas nonwhite males IStatisticaIly significant at the 0.05 level - 1 -Tabb 9. Mortalii for Selscted Cancer Sites in Whae Male OCAW Members Employed at Plant A by Length of Union Membership. I < 10 Ywn (N = 107) Length of Membership 10-19 Years (N = 177) Sia (8th Revision. ICD) 0' E t PYR 0 E PMR Stomach (151) 3 1.4 - 1 2.2 - Brain 8 central nervous system (191.192) 0 0.8 - 5 1.5 3.32$ 4 1.1 '0 = Observed deaths t E = Expected deaths based on proportionate mortality for U.S. white males $Statistically significant at the 0.05 level -Not calculated - - -Tabla 10. Mortality for Selected Cancer Sites in OCAW Members Employed 11 PIaM B bv Lenath of Union Membershio. 1 - Whine Mabs Nonwhite males Sir (8th R6vision, ICO) Length of Membership < 10 Ywrs 10+ Yean (N = 111) (N = 191) 0' E t PMR 0 E PMR (N = 111) 0 E PMR Stomach (151) I 1.7 - 6 2.0 2.97$ 7 2.1 3.404 Lung (162.163) Skin (172,173) Kidney (189) Leukemia (204-207) 5 -1 - -1 3 4.5 0.4 1 .-1 1 0.5 0.9 - 13 12.1 1.08 13 3 3 0.8 1.0 - 3 1.5 - 0 0 0 4.4 0.1 2.-943 0.3 0.4 - '0 = Observed deaths t E = Expected deaths based on proportionate mortality for U S males $Statistically significant at the 0 05 level -Not calculated cancer, cancer of the brain, leukemia, and multiple myeloma increase with longer Union membership among workers in the refinery and petrochemical category strengthens the possibility of an association with occupational factors. Furthermore, essentially the same relationships were seen in a proportionate cancer mortality analysis. These findings are consistent with reports of an excess of stomach cancer deaths among Canadian petroleum refinery workers,' and of an elevated risk of leukemia associated with exposure t o benzene and perhaps other petrochemicals."l 4 I s Studies of vinyl chloride workers have shown an increased relative frequency of brain tumors;15 I' however, no association between employ- ment in refineries and petrochemical plants and excess mortality from brain tumors has previously been reported. Although no positive gradient in risk with length d Union membership was detected for cancers of the creas, liver, lung, and skin, further evaluation of these sites should be made. PMR analysis using Texas males I a comparison group does not alter the conclusions; thert fore, these findings cannot be explained by high T W rates. The lack of a gradient raises the possibility that fxtors other than occupational exposure may be operating; however, occupational factors cannot be completeb ruled out because some cancers may have shorter latent periods, depending upon the nature of the exposure. In addition, this study has highlighted three specific plants in which Union members appear to have increased 102 Mortality Among Workers in Petroleum Refining and PetrochemicalPlants/Thomas. Decoufle, and Moure-Eras ' i I risks of certain cancers - of brain cancer at Plants A and C, of stomach cancer at Plants A and B, and of lung C-mer at Plants B and C. Further evaluations of mortality among workers at these plants will be made. &spite limitations in data and in methodology, results of the present study suggest that workers in this industry are at increased risk of certain cancers. Further studies are necessary to support and clarify these findings ThC a & o s wish to thank DN 1. F. Fraumeni. Ir., R. Hoover. A. Blair. I . walnth and Ms 5 Krekel for support and guidance. 5 . Mayfield. T Prante. M. R-, and D Watts for t e c h n d assistance; and M. Classer for manuscript prpuatm. References 1. Blot WJ.Brinton LA, Fraumeni IF. and Stone BJ:Cancer mortality in U.S counties with petroleum industries. Science 1W.51-53. 1977 2. Hendricks NV, Linden NJ, Berry CM. et al. Cancer of the scrotum in wax pressmen A.M.A. Arch Ind Health 19524-529, 1959 3. Weil CS. Smyth HF. and Nale TW. Quest for a suspected industrial carcinogen A.M.A. Arch IndH y g 5:535-547, 1952. 4. b i r d VC: Effects of atmospheric contamination on cancer mort a l w in petroleum refinery exployees. / Occup Med 9415-420, 1%7. 5. TabershawlCooper Associates: A mortality study of petroleum rdinecy workers. Project OH-1 prepared for the American Petroleum Imtihrte. Washington, D C.. 1974. 6. Wade L: Observations on skin cancer among refinery workers Arch Environ Health 61730-735. 1963. 7 Hank NM, Stavraky KM, and Fowler JL: Cancer mortality in oil refinery workers. / Occup Med 21:167-174, 1979. 8. Considine DM (Ed.): Chemical and Process Technology Encycle pedia. New York: McCraw-Hill. 1974. 9. International Classification of Diseases (Eighth Revision). Geneva: WHO, 1967. 10. Monson RR: Analysis of relative survival and proportional mor- talih.. Comput Biomed Res 7:325-332, 1974. 11.Mantel N and Haenszel W: Statistical aspects of the analysis of data from retrospective studies of disease. Natl Cancer lnst 22:719-748. 1959. 12. McMichael AI. Haynes SC, and Tryroler HA: Obse&ations on the evaluation of occupational mortality data. ) Occup Med 17128-131. 1975. 13. Vigliani EC and Saita C.Benzene and leukemia. N Eng// Med 271:872-876. 1964. 14. Infante PF, Wagoner JK,Rinsky RA, and Young RJ: Leukemia in benzene workers Lancet 2:76-78, 1977. 15. McMichael AJ, Spirtas R, Kupper LL, and Gamble IF:Solvent ex- posure and leukemia among rubber workers: An epidemiologic study. I OCCUPMed 17234-239, 1975. 16. Monson RR and Peters JM;Proportional mortality among vinyl chloride workers Lancet 2:397-398. 1974. 17. Tabershaw IR and Caffey WR: Mortality study of workers in the manufacture of vinyl chloride and its polymers. ) Occup Med 16:509-518, 1974. 18. Waxweiler RJ, Stringer W, Wagoner JK. et al: Neoplastic risk among workers exposed t o vinyl chloride. Ann NY Acad Sci 27140-48, 1976. Meaning of Work For many persons, work is a vital part of the process of coping with life stress. This has two apsects: first, without work, the potential for boredom and meaninglessness is immeasurably increased. Work is often the primary means by which a person feels useful in life and throvgh which significance and personal identity are established.The young adult must find a useful and meaningful place in society, and only in this way does a man or woman develop a firm sense of identity. Second, work is often a form of coping and a refuge. Consider, for example, how people in grief regard work. Many report that in the process of mourning and reorienting their lives after a major loss, work is not a burden, but the best refuge against cow stant high levels of distress and depression. One speaks here of "burying one's self in work." Thus, work may provide a psychological haven against problems that otherwise would be insurmountable, or against loneliness and depression. For such people not to work is to be deprived of the only viable means of coping with nomwork-relatedstress. - From Work Stress by Alan A McLean AddisowWesley Publishing Company. Reading, Massachusetts.1979 Journal of Occupational Medicine/Vol. 22, No. 2lFebruary 1980 i, 103