Document O1Nkvn6wE1go2zX1G7b6286BX

pcrted by a grant from the City of Birmingham, for his skillful assistance with the analytical work. They are also grateful to the staff of the City of Birmingham Dental Clinics for supplying teeth for analysis. Accepted for publication June 26, 1976. Article'oopies are available from Dr. Harry A. Waldron, Depart ment of Social'Medicine, Thp Medical School, Birmingham B15 2TJ, United Kingdom. x**V******** REFERENCES Strehlow, C.D. 1972. The use of deciduous teeth as indicators of lead exposure. Ph.D. dissertation. New York University. .2 Needleman, H.L.; Davidson, I.; Sewell, EAL; and Shapiro, I.M. 1974. Subclinical lead exposure in Philadelphia schoolchildren: Identification by dentine lead analysis. NEngl/Med 290: 243-. 48. KehoepR^^ 3. Altschuler, L.F.; Hatak, D.B.; Landing, BJL; and Kehoepl 1962. Deciduous teeth as an index of body burden ^E-tSad.s.. J Peeliarr 60: 224-29. 4. Needleman, HX.; Tuncay, O.C.;and ShapirprT.M. 1972. Lead levels in deciduous teeth of urban and suburban American children. Nature 235: 111-12. S' 5. Stewart, DJ. 1974. Teeth as indicatorst ot f exposure of children . to lead. Arch Dis Child 49^895-97. 6 Kaneko, Y.; Inamori, L>nd Nishimura, M. 1974. Zinc, lead, copper, and cadmiunrui human teeth from different geo graphical areas in^Cpan. Bull Tokyo Med Dent L'niv 15: 233- 41. 7. Shapiro, l.biZ Mitchell, G.; Davidson, L; and Katz. S.H. 1975. The leacLbontent of teeth: Evidence establishing new minimal levels^df exposure in a living preindustrialized human popula- . tioprlArch Environ Health 30: 483-86. 8 Mackie, A.C., and Townshend, A. In press. Evaluation of pro/cedures for tooth lead analysis.Analyst, it Lockeretz, W. 1975. Lead content of deciduous teeth of chil dren in different environments. Arch Environ Health 30: 583- 10. Steadman, L.T.; Brudcvold, F.; Smith, F.A.<16ardner, D.E.; and Little, M.F. 1959. Trace eiementsin'ancient Indian teeth. /Dent Res 33: 285-91. 11. Pfrieme, F. 1934. Uber den nosmalen und pathologischen Bleigehalt de: Zahne von Mehschen und Tteten.Arch Uyg Bakteriol 11: 232-42. X 12. Storozheva, N.N. 1963. Soderzhanie svitsa i dova v zubakh cheloveka v norme i pri kariere. Stomatologiia (Mosk) 42: 44-48. / 13. Wilkinsooc'O.R., and Palmer, W. 1975. Lead in teeth as a func tion oEige. Am Lab 41: 67-70. 14. Strdfilow, C.D., and Kneip, TJ. 1969. The distribution of lead and zinc in the human skeleton. Am Ind Hyg Assoc J 30: 372-78. 15. Holtzman, R.B.; Lucas, HJ.; and llcewicz, F.H. 1968 'Con centration of lead in human bone. Argonne National Labora tory publication no. Anl-7615, pp. 43-49. 16. Malik, S.R., and Fremlin, i. 1974. A study of lead distribu tion in human teeth, using charged particle activation analysis. Caries Res 8: 283-89. 17. Mackie, A.C.; Stephens, R.; Townshend, A.; and Waldron, ILA. In press. Lead and caries. Caries Res. 18. Stack. M.V.; Burkitt, AJ.; and Nickless. C. 1975. Lead in children's teeth. Nature 255: 169. 19. Joint Working Party on Lead Pollution around Gravelly Hill. 1975. Interim report. London: Department of the Environ ment. 20. Hunter, R.E.; Kelsall, NLA.; Bishop, WJ.; and Woodworth, P.F. 1973. Abstracts of the 4th, International Conference on Atomic Spectroscopy. Toronto, Ontario: International Con ference on Atomic Spectroscopy, p. 36v-. 21. Chatman, T., and Wilson, DJ. 1975. Lead levels in human deciduous teeth in Tennessee. Environ Lett 8: 173-83. 22. Rytonua, L., and Tuompo, H. 1974. Lead levels in deciduous teeth. Natunvissenschaften 61: 363. Cancer Mortality in Relation to Asbestos in Municipal Wa rmliies DONALD T. WIGLE, M. D., Ph-D., M.P.H. Bureau of Epidemiology Health and Welfare Canada Ottawa, Ontario ABSTRACT The mortality experience of twenty-two municipalities in Quebec grouped by evidence'SRJJosur^c^sEesfo^IEeTsTn water supplies (known high, possible high, and probable low exposures) was evaluated. Excess mortality due to cancer of the stomach (males), pancreas (females), and lung (males) was observed in the two municipalities with known high exposures. The excesses among males may have been due to occupational exposure to asbestos. The absence of excess mortality due to pancreatic cancer among males suggested that the excess among females was not due to waterborne asbestos. The study therefore did not reveal _ evidence of cx<* eanc-er mortality thst rrmld he attributed IP tn ir'mTniin i'i lulling infrr, ALTHOUGH ASBESTOS is a well-characterized car cinogenic agent when inhaled by humans,1 there is little evidence concerning its carcinogenicity when ingested. As bestos fibers were discovered in Lake Superior, the source of municipal water for Duluth, Minnesota, in 1973. Further investigation revealed the presence of 1-30 million amphibole asbestiform fibers per liter in Duluth tap water sam ples. Contamination of the water supply with asbestos ap parently began in 19SS as a result of the dumping of taconite mine-tailings into the lake. Thus, the studies re ferred to below1,3 probably did not include a sufficient time period to observe an increased risk of cancer due to exposure to waterborne asbestos. A study of cancer mortality2 during four 5-year periods beginning in 1950 revealed that, relative to the state of Minnesota, the city of Duluth had significant excess mor tality due to several cancer sites at least one time period. The gastrointestinal sites involved were cancers of the esophagus, stomach, and rectum in white males, and can cers of the rectum and pancreas in white females. However, only the rate for male rectal cancer increased during the time periods subsequent to 1955-59; the female rectal can cer rate increased between 1950-54 and 1955-59, that is, before or soon after the dumping of taconite tailings began. An interval of 10 to 20 or more years before development of cancer would be expected for most human carcinogens. July/August 1977 HER 0000996 185 In another study, incidence rates during 1969-71 were significantly high, in Duluth compared with Minneapolis for stomach cancer (males) and compared with either Niirmeapolis or St. Paul for cancer of the pancreas (both sexes), but were significantly lower in Duluth than in either comparison city for cancer of the large intestine.1 The present study was undertaken to evaluate cancer mortality in two municipalities, Thetford Mines and Asbes tos, where asbestos mining operations were established many years ago, in 1878 and 1882, respectively. Recent studies4 (R. W. Durham 1975: personal communication) have revealed the presence of relatively high concentrations of asbestos fibers in the municipal water supplies of Thet ford Mines and Asbestos. The asbestos deposits in the re gion of these municipalities consist mainly of chrysotile in serpentinized peridotite.5 Method Tabulations of the number of deaths by three-digit rubrics of the International Classification ofDiseases, seventh revision (1964-68) and eighth revision, adapted for use in the United States (1969-73), 5-year age group, sex, and municipality were obtained from the Health Division of Statistics Canada. The 1966 and 1971 pop ulations by age, sex, and municipality were obtained from the Census Data Dissemination Division of Statistics Canada. The municipalities included are as follows: In Group 1 (known high exposure)--Asbestos and Thetford Mines; in Group 2 (possible high exposure)--Black Lake, Drum mondville, Drummondville Sud, Magog, Plessisville, Victor- iaville, and Windsor; in Group 3 (probable low exposure)-- Alma, Arvida, Becancour, Grand' Mere, Joliette, La Tuque, Nicolet, Rimouski, Rimouski Est, Riviere-du-Loup, Shawinigan, Shawinigan Sud, Soret-Tracy, St. Hyacinthe, St. Jerome, and Ste. Therese. The expected numbers of cancer deaths were calculated by applying the Quebec age-specific (5-year groups), sexspecific, site-specific, and period-specific (1965-67,197072) mortality rates to the 1966 or 1971 census popula tions by age and sex for each municipality. Results Characteristics of Grouped Municipalities The locations of the municipalities in each of the three groups are shown on the map in the figure. The two towns with known high exposures (Group 1) and the six towns with possible high exposures (Group 2) are clustered within a radius of about 40 miles and either are immediately ad jacent to asbestos-containing deposits or obtain drinking water from rivers draining the region of such deposits. Towns with probable low exposures (Group 3) were sel ected from regions remote from the peridotite deposits shown in the figure. The available data concerning the concentration of asbestos fibers in the municipal water supplies are presented in Table 1. The results for Asbestos and Thetford Mines indicate asbestos fiber concentrations substantially higher than those for Drummondville (filtered) or Plessisville. There is a large discrepancy in the values reported by the two sources for Thetford Mines, but both values are high. Selected demographic characteristics of the three Location of municipalities and peridotite deposits. HI, Asbestos; H2, Thetford Mines;PI, Black Lake;P2, Drummondville and Drummondville Sud;AJ, Magog;P4, Plessisville; PS, Victoriaville; Ad, Windsor; LI, Alma; 2, Arvida; L3, Becancour; L4, Grand' Mere; LS, Joliette; L6, La Tuque; L 7, Nicolet; LA, Rimouski and Rimouski Est; 9, Rivere-du-Loup; / 0, Shawinigan and Shawinigan Sud: //, Sorel-Tracy: LI2, St. Hyacinthe; LI3, St. Jerome; Li4, Ste. Therese. 186 Archives of Environmental Health HER *0000997 Table l.-Available Data for Asbestos Fibers in Municipal Water Supplies __________________ ____ Municipality and Type of Water Supply Source Reported Concentrations * of Asbestos Fibers in Municipal Water Supply Asbestos Raw Filtered 1300.000,090* 200,000,00*>f Thetford Mines Raw Raw 172,000,000i 1300.000,000 f Drummondville Raw Filtered 680,000,000* 1,100,0001 Plessisville Raw 13,000,000 * * Fibers per liter. j R. \V. Durham 1975: personal communication. $ See reference 4. Municipal water supply is not filtered. groups of municipalities are presented in Table 2. The three groups were quite similar with respect to mother tongue (French) and proportions of the labor force em ployed in major occupational groups 11-33 (professional, administrative) and 41-61 (clerical, sales, service). The average population was somewhat larger for Group 3 than for Group 1 or 2. Groups 1 and 2 had the highest proportions of the labor force in major groups 77 (min ing, quarrying) and 81-85 (processing, machining, pro duct fabricating), respectively. General Mortality The observed (0) and expected (E) numbers of deaths due to all cancer and all other causes by municipality group and sex are presented in Table 3. Significant excesses of cancer deaths were observed among males in Group 1 (0/E = 1.23) and females in Group 3 (0/E = 1.07). There were significant excesses of deaths due to all Table 2.--Characteristics of Grouped Municipalities Characteristic Group 1 Group 2 Group 3 (Known High (Possible High (Probable Low Exposure) Exposure) Exposure) Number of municipalities 2 6 14 Population* Average Total 15,857 31,714 15,603 93,620 21,028 294,396 Percentage with French as mother tongue 95.9 97.2 96.6 Percentage in major occupation groups! 11-33 41-61 77 81-85 Other 17.2 303 11.1 16.2 25.0 15.8 33.2 0.8 26.8 23.3 18.9 33.7 0.1 19.9 27.4 By 1971 census. t 11-33-managerial, professional, artistic, literary, recreational; 41-61-derical, sales, service; 77-mining, quarrying; 81-85processing, machining, product fabricating. Values shown represent the percentage of the experienced labor force, aged 15 years and over, for both sexes, in 1971. other causes among males in all three municipality groups (0/E = 1.12,1.08, and 1.10) and among females in Group 3 (O/E = 1.10). The distribution of mortality was also studied for the individual municipalities within each of the three groups (data not shown but available upon request). Significant excesses of deaths due to all cancer were observed as follows: Group 1--Thetford Mines (males, O/E = 13); Group 3--Joliette (males, O/E = 13), La Tuque (males, O/E =13), Nicolet (females, O/E =1.8), St. Hyacinthe (females, O/E = 13), and Ste. Therese (females, O/E = 13). The municipalities having significant excesses of deaths due to all other causes were: Group 1-Asbestos (males, O/E = 13); Group 2--Drummondville (males, O/E = 1.1); Group 3--Alma (females, O/E = 1.4), Joliette (males, O/E = 13; females, O/E =1.1), Nicolet (females, O/E = 13), Riviere-du-Loup (males, O/E = 13), Sorel- Table 3.-Mortality Due to All Cancer and AD Other Causes > Cause of Death, Group 1 Group 2 (Known High Exposure) (Possible High Exposure) ---- and <s Sex Obs Exp* O/E Obs Exp O/E Group 3 (Probable Low Exposure) -------------- Obs Exp O/E All cancer M F T 195 127 322 158.4 1383 296.6 1.23? 0.92 1.09 457 415 872 Other causes M F T 601 259 860 536.2 285.4 821.6 1.12$ 1,690 0.91 893 1.05 23S3 NOTE: The 25-74 age group was considered. See Methods section of text f/><.05, by the chi-square test. $/* <.01, by the chi-square test. 466.0 408.9 874.9 1,562.1 858.3 2,420.4 0.93 1.01 1.00 1,433 1302 2,735 1.08$ 1.05 1.07 5,148 2,809 7.957 July/August 1977 v 1389.8 1319.8 2,609.6 1.03 1.07f 1.051 4,679.1 2348.3 7,227.4 1.10$ 1.10$ 1.10$ HER 0000998 187 Tracy (males, O/E = 1.1), St. Hyacinths (males, 0/E = 1.1; females, 0/E = 1.1), and Ste. Thcrese (females, 0/E =1.2). Cancer Mortality The observed and expected numbers of cancer deaths by sex, site, and municipality group are presented in Table 4. Significant excesses of cancer deaths were ob served as follows: Croup 1--stomach (males), pancreas (females), lung (males); Group 2-prostate (males), kidney (females), brain (males), lymphoma (females); Group 3--large intestine except rectum (females), uterus except cervix (females), and kidney (females). The distribution of gastrointestinal cancer by age group, sex, and aggregated sites is presented in Table 5. Significant excesses of cancer deaths were observed for the following: Group 1-upper gastrointestinal (females aged 75 and over, and total); Group 3--large intestine and rectum (males aged 75 and over); and total gastroin testinal (males aged 75 and over). Discussion Studies of workers exposed to asbestos have revealed excess mortality due to gastrointestinal cancer,7 and abdominal mesotheliomas.'9 Such observations may in dicate that exposure to asbestos via the gastrointestinal tract (presumably from swallowed sputum in workers exposed to airborne asbestos) increases the risk of cancer Table 4.--Cancer Deaths by Sex and Major Site Croup 1 (Known High Exposure) Site Sex Obs Exp* O/E Croup 2 (Possible High Exposure) Obs Exp O/E Group 3 (Probable Low Exposure) Obs Exp O/E Buccal cavity and pharynx Esophagus Stomach Large intestine except rectum Rectum Pancreas Lung Breast Cervix uteri Other uterus OVary Prostate Kidney Bladder Brain Lymphoma Leukemia Other M F M F M F M F M F M F M F F F F F M M F M F M F M F M F M F 4 1 3 l 24 10 18 14 4 4 8 9 78 10 29 7 7 9 9 2 2 4 1 2 1 6 3 6 2 27 17 5.8 1.5 3.5 1.1 17.4 8.7 14.0 16.8 7.0 5.0 8.4 5.2 46.8 7.7 35.0 8.7 7.1 8.6 7.7 3.8 2.1 6.0 1.5 4.8 3.6 8.8 6.5 5.4 3.7 19.0 15.4 0.7 ... ... -- 1.4f 1.2 1.3 0.8 0.6 0.8 1.0 l-7t 1.7$ 1.3 0.8 0.8 1.0 1.0 1.2 ... 0.7 ... 0.7 0.5 1.1 ._ 1.4f 1.1 11 17.0 0.6t 3 4.4 ... 5 10.5 0-5f 2 3.2 ... 47 51.6 0.9 35 26.0 1.3 41 41.0 1.0 57 50.5 1.1 20 21.3 0.9 9 14.8 0.6f 29 24.8 1.2 18 15.7 1.1 106 137.5 17 22.9 0.8$ 0.7 106 98.8 1.1 26 25.0 1.0 19 21.1 0.9 22 25.4 0.9 44 24.1 1.8$ 9 10.9 0.8 10 r 6.3 1.6$ 10 18.0 0.6f 2 4.5 25 13.3 1.9$ 5 10.5 0.5t 30 25.0 1.2 24 19.2 1.3f 18 15.7 1.1 9 10.9 0.8 62 55.3 l.l 51 49.7 1.0 54 50.8 9 13.0 26 30.8 3 9.5 145 153.6 91 77.1 126 122.2 176 149.4 51 61.5 44 43.8 91 74.2 44 46.8 392 409.9 54 68.5 303 305.5 74 75.3 80 62.3 75 75.8 81 70.9 28 32.6 24 18.9 51 53.0 11 13.4 42 40.3 37 31.7 86 74.5 59 57.5 56 46.9 35 32.6 204 167.6 183 138.7 1.1 0.7 0.8 0.3f 0*9 1.2 1.0 1.2f 0.8 1.0 1.2 Q.9 1.0 0.8 1.0 1.0 Uf 1.0 1.1 0.9 1.3f 1.0 0.8 1.0 1.2 1.2 1.0 1.2 1.1 1.2$ 1-3$ NOTES: Only the 2S-74 year age group was considered. 0/E was not calculated if E (expected number of deaths) was less than 5. ~ See Methods section of text. tP<'.05, by the chi-square test if E>20 and by Poisson distribution if E <20. $P<.01, by the chi-square test if E >20 and by Poisson distribution if E <20. 188 _r Archives of Environmental Health n' V HER 0000999 Table 5.-Gistrointestinai Cancer Mortality By Aggregated Silas. Age, and Sex Croup 1 (Known High Exposure) Croup 2 (Possible High Exposure) Croup 3 (Probable Low Exposure) Cancer Site Sex Age Obs Exp* 0,'E Obs Exp O/E Obs Exp O/E Upper - casuointc$tinal M 25-74 75+ Total 31 11 42 26.8 1.2 63 10.7 1.0 51 37.5 1.1 114 7S.9 39.1 118.0 0.8 1.3 1.0 225 235.0 1.0 118 106.8 1.1 343 341.8 1.0 F Larze intestine and rectum M 25-74 75+ Total 12 11 23 25-74 75+ Total 11 3 25 11.2 5.3 16.5 20.9 8.8 29.7 1.1 2.1t l-4f 1.1 0.3+ 0.8 40 27 67 61 33 94 33.5 22.6 56.1 623 213 94.8 13 1.2 1.2 1.0 1.0 1.0 103 99.5 1.0 70 70.9 1.0 173 170.4 1.0 177 183.7 1.0 115 89.4 1-3* 292 273.1 1.1 Total F 25-74 18 21.8 0.8 66 65.2 1.0 220 191.6 1.1 75+ 8 9.7 0.3 39 41.5 0.9 136 130.0 . 1.0 Total 26 315 0.8 105 106.7 1.0 356 321.6 1.1 M 25-74 53 47.7 1.1 124 141.2 0.9 402 418.7 1.0 75+ 14 19.5 0.7 84 71.6 1.2 233 196.2 13t Total 67 67.2 1.0 208 212.8 1.0 635 614.9 1.0 F 25-74 30 33.0 0.9 106 98.7 1.1 323 291.1 1.1 75+ 19 15.0 1J 66 64.1 1.0 206 200.9 1-P Total 49 48.0 1.0 172 162.8 1.1 529 492.0 1.1 See Methods section of text. fP <.05, by the chi-square test if E (expected number of deaths) > 20 and by Poisson distribution if E <20. +P<.01,by the chi-square test if E>20 and by Poisson distribution if E <20. Buccal cavity, pharynx, esophagus, and stomach. in tissues directly or indirectly exposed to the fibers. This possibility has caused some concern about the presence of asbestos fibers in municipal water supplies both in the United States2 ,J and in Canada.4,10 The present study revealed some evidence of excess mortality due to gastrointestinal cancer in the two munic ipalities in Croup 1 (known to have water supplies con taining high concentrations of asbestos fibers). The individual sites for which there were statistically signif icant excesses of gastrointestinal cancer in these two municipalities were the stomach (males) and the pancreas (females). In Duluth, a significantly high incidence of pancreatic cancer was observed in both sexes. The present study does not support an association between pancreatic cancer and exposure to asbestos fibers in drinking water, because there was no excess among males. The excess stomach cancer among males may reflect occupational exposure to asbestos; the absence of an excess among females argues against a role for waterborne asbestos. Ex cess mortality due to stomach cancer has previously been observed in asbestos workers.6,7 The excess male mortality due to lung cancer observed for the two municipalities in Croup 1 (Asbestos and Thetford Mines) was mainly due to an excess in Thetford Mines (0 = 58, E = 31.6). This observation is consistent with the reportedly higher prevalence of opacities, pleural thickening, and pleural calcification, as diagnosed by chest roentgenography of asbestos workers,11 in Thetford Mines than in Asbestos. The substantial excesses of deaths due to pro static and brain cancer among males in Group 2 municipalities (pos sible high exposure to asbestos) deserve further investiga tion, but do not appear to be related to waterborne asbes tos since similar excesses were not observed in Group I, and the excess of brain cancer in Group 2 was confined to males. Conclusion A study of twenty-two municipalities in Quebec did not reveal excess cancer mortality that could be related to the presence of asbestos fibers in drinking water supplies. Ex cess mortality due to stomach and lung cancer among males in two municipalities (Asbestos and Thetford Mines) may reflect occupational exposure to asbestos. The tabulation of mortality data by John SBins and Pio Uran and the assistance in data analysis by M. Honora Smith are grate fully acknowledged. Submitted December 21,1976; accepted for publication Februaty 28, 1977. Article copies are available from Dr. Wigle at the Bureau of Epidemiology, L. C. D. C., Health and Welfare Canada. Tunney's Pasture, Ottawa, Ontario, K1A OL2, Canada. REFERENCES 1. Report of the Advisory Committee on Asbestos Cancers to the Director of the International Agency for Research on Can cer. Br J tndur.rMxi 30(1973): 180-86. Julv/August 1977 f. HER 0001000 i89 2. Mason, T. J.; McKay. F. W.; and Miller. R. W. 1974. AsbestosIiaC fibers in Duluth water supply: Relation to cancer mortality. JAMA 228: 1019*20. 3. Levy, B. S.; Sigurdson, E.; Mandcl. J.; Laudon, E.; and Pearson, J. 1976. Investigating possible effects of asbestos in city water: Surveillance of gastrointestinal cancer incidence in Duluth, .Minnesota. Am J Epidemiol 103: 362-68. 4. Cunningham, H. M.f and Pontefract. R. D. 1971. Asbestos fibres in beverages and drinking water. Nature 232: 332-33. 5. Gibbs. G. W., and Lachance, M. 1972. Dust exposure in the chrysotile asbestos mines and mills of Quebec. Arch Environ Health 24: 189-97. 6. Sclikofr. I. J.; Hammond, E. C.; and Churg, J. 1968. Asbestos exposure, smoking, and neoplasia. JAMA 204: 104-10. 7. McDonald, J. C.; McDonald, A. D.; Gibbs, G. W.; Sicmiatycki, J.;and Rossitcr, C. E. 1971. Mortality in the chrysotile asbestos mines and mills of Quebec. Arch Environ Health 22: 677-86. 8. Ncwhouse, M. L.; Berry. G.; Wagner, J. C.: and Turok. M. U. 1972. A study of the mortality of female asbestos workers. Br J Industr Med 29: 134-41. 9. Sclikoff, 1. J.; Hammond, E. C.; and Churg, J. 1972. Carcin ogenicity of amositc asbestos. Arch Environ Health 25: 183-86. 10. Kay, C. 1973. Ontario intensifies search for asbestos in drinking water. Water Pollut Control (Sept. 1973): 33-35. 11. McDonald, J. C.; Bccklakc. M. R.; Gibbs, G. W.; .McDonald, A. D.; and Rossiter, C. E. 1974. The health of chrysotile asbestos mine and mill workers of Quebec. Arch Environ Health 28: 61-68. Director of Environmental Health Engineering for Bethlehem Steel Corporation Our Environmental Quality Control Division has an opening for an experienced Environmental Health (Industrial Hygiene) Engineer to direct our Environmental Health Engineering Program. Required qualifications are: An undergraduate engineering degree with a graduate degree in environmental health (industrial hygiene); S to 10 years experience in the technical aspects of workplace evaluations and the application of engineering control techniques; and several years experience in administering a comprehensive industrial hygiene engi neering program. Excellent benefits, opportunities for further study, ultra-modem facilities, and attractive working con ditions in a pleasant cultural community. Send resume and salary requirements in confidence to: Dr. D. M. Anderson. Manager Environmental Quality Control Bethlehem Steel Corporation * Bethlehem. PA 18016 An Equal Opportunity Employer Work in fresh air all day. MSA Air-Line Respirators. Choice of constant-flow demand or pressure-demand- flow systems to protect workers in toxic atmospheres not immediately hazardous to life or health. Variety of facepieces, as well as spe cial iu-ods for working with abrasives, sandblasting and lead grinding. Write for details to M$A. 600 Penn Center, Pittsburgh. Pa. 1S23S. Make sure/check MSA SSeEJ 190 Softsnugj effective. Accu-FitTM and Ear Defenders1 Earplugs. Comfortable enough to wear all shift to guard against noise considered harmful on long exposure. Accu-Fit Ear Plugs are pliable, with one size to fit most people. Ear Defenders come in five sizes with EarscopeTM gage to find correct size. Write for more details to MSA. 600 Penn Center, Pittsburgh. Pa. 15235. Make sure/check MSA !< "I Archives of Environmental Health HER 0001001