Document OzDzgMKZ57rxVOyza8GxJpM6K

Vol 188, No 1 Editor John H. Talbott, MD NO Managing Edjtor: Robert W, Mayo Senior Editors: Zenonas Danilevicius. MD, Lester S. King, MO, John H. Raach, MD, Alfred Softer, MO. M. Therese Southgate, MO 1 THE JOURNAL of the American Medical Association APRIL 6, 1964 Published under the auspices of the Board of Irustoes. Copyright 1964 by Hi* Amftficon Modlcol Atiociotion Department Editors: Charles F. Chapman . (Special Projects), Robert O. Hershberger . (Copy), Robert W.Riley (News).Frances Stern - (Deaths) Art and Layout: John C. Heavey (Supervisor). . Thomas Handrigan, NancyHawke - Production --Makeup: Wallace E. Myers . Administrative Assistant: Lulu M. Fisher . Medical News (Assistant Editors): B. Kay An* . derson, Elizabeth G. Barley, Paul 0. Schultz, . Lydia A. Woods . .t ' Copy Editing: iMary R. Gardner, Karen Knut* son; Evalyn-Kuhn, Jjhth Lambert. Marilyn / . Meyer, Victoria .Morey, Sharlene Polk, Sharort ' * Stephenson ; . .. >.- r Abstracting: Karen :Breinig, Felix Cisneros, . . Irmgard P. Palusinski, Elizabeth Sieweke/ y.{.VvV:;Eriedrich'i'Sternthalr>,l|ona Zichy 1 ; . .. '' . . Washington News: Ted Lewis . - Editorial Assistants: Sharon J. ..Cranford, - Marlene M. Hinsch, Joyce Kinloch, Mary Lind . berg. Margaret Muscarello. Betty. Nickrandt, ' Merry Uchida, Margery Zyck -. Makeup Assistants: Janice M. Cawley, Renell Kirsbenbaum, Marilyn Markowski ' ' . Manuscript Record:-Margaret Bruzas ' Communications Operations: FlorencevMeyer (Supervisor). Elsie McGowan. Ruby Ross ' Secretarial Staff: Monica Borgwardt, Carol. Gulli, Joanne Guljas, Joyce Kinzalow, Steph anie Poremski. Susan Roeth, Monique Szeliga Indexing: Susan Y. Crawford, Phyllis H. McLaren Executive Vice-President F. J. L. Blasingame, MD Circulation Manager . Robert A. Enlow Advertising Manager John L. Murphy Business Manager Russell H. Clark CONTENTS CONTINUED JUST WORDS ............................................................................................................................. . 68 COMMITTEE ON REHABILITATION ............................................................ Rehabilitation of the Alcoholic M. A. Block, Ml). Huffalo 84 . . : LETTERS .............................................................................................. Treatment for Barbiturate Intoxication . . . Personnel Selection in the Medical Sciences . . . Contraindications to Long-Term Fasting . 87 ' .,... THE BOOK FORUM .......................................... 89 QUESTIONS AND ANSWERS ........................................................................ Fluoridated Water and Dental Caries . . . Pressure Urticaria . . . Transient : Edema of the Arm . . . Allergy to Contrast Media . . . Gamma Globulin and Upper Respiratory Infections . . . Coldness of Extremities.. . . Sodium in Atmosphere . . . Cleansing of Lacerations . . . Postpartum Vein Surgery Site of Injection of Penicillin - 92 . ..... v.'C INTERNATIONAL COMMENTS ............................................................... . . .. 96 . DEATHS :................................................................................................................ . 99 , WASHINGTON NEWS ......................... .............. ....................... Adv Page ,rii Controversy Over Cigaret Labeling . . . AMA on Drug Evaluation . . . FDA : .... Warning on Tannic Acid ' . ,..... '..C, MEDICAL NEWS...........................................................................................Adv Page AMA Presents Cigaret Labeling Views to FTC . . . Newspapers Comment- ; ; on Labeling . . . Text of AMA Letter of Testimony to FTC : . FROM OTHER PAGES ....................................................................................... Adv Page 44- REFERENCE DIRECTORIES Meetings in the United States .................................................. ..................Adv Page 49 - INTERNATIONAL AND FOREIGN MEETINGS ...............................................Adv Page 99 MAGAZINE-TV REPORT .......................................................................................... Adv Page 104 .. REFERENCES AND REVIEWS .....................................................................:.........Adv Page 224 SATIRE ......................................................................... ................................................ Adv Page 259 : SMILE A WHILE ....................................................................................................... Adv Page 276,., CLASSIFIED ADVERTISING .................................................................................. Adv Page 287.,- INDEX TO ADVERTISERS ..................................................................................... 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ADVERTISING PRINCIPLES - Advertise' ments in this issue have been reviewed tocomply with the principles governmg advertising in AMA scientific publications. A copy of these principles is available upon request from the Advertising Department.1 SC-ALL-11480 SCF-FA-5420 A f j: jfi I $ V'.- i 'i i ) i ''! M vi?. .v-i , ? / V 22 JAMA, April 6, 1964 Asbestos Exposure and Neoplasia Irving J. Selikoff, MD, Jacob Churg, MD, and E. Cuyler Hammond, DSc, New York Building trades insulation workers have relatively light, intermittent, exposure to asbestos. Of 632 insulation workers, who entered the trade before 1943 and were traced through 1962, forty-five died of cancer of the lung or pleura, whereas only 6.6 such deaths were expected. Three of the pleural tumors were mesotheliomas; there was also one peritoneal mesothelio ma. Four mesotheliomas in a total of 255 deaths is an exceedingly high incidence for such a rare tumor. In addition, an unex pectedly large number of men died of can cer of the stomach, colon, or rectum (29 compared with 9.4 expected). Other can cers were not increased; 20.5 were expected, 21 occurred. Twelve men died of asbestosis. ALTHOUGH PULMONARY CARCINOMA had XT-been observed in the earliest studies of asbes tosis, association between the two conditions was first suggested by Lynch and Smith in 1935.1 Ad ditional reports of such association followed. Per haps the most striking data was presented in the annual report of the Chief Inspector of Factories of Great Britain for 1955.2 Every death with as bestosis in the files of the Factory Department, from the first recognition of asbestosis as a disease entity, was studied. Altogether 365 such deaths were recorded (1924-1955). Sixty-five or 17.8% were found to be accompanied by cancer of the lung or pleura. Doll,3 after reviewing the problem and add ing data of his own, concluded that lung cancer was a specific industrial hazard of heavily exposed asbestos workers. Nevertheless, some investigators have held that, while these observations might be suggestive, they did not establish an increased incidence of carci noma of the lung in pulmonary asbestosis, and further,, that the association was unproved. The factor of selection was considered a poten tial weakness in evaluating reports of autopsy series. It was noted that complicated and unusual cases would be more likely to come to autopsy, thus raising the apparent frequency of associated lung neoplasms.4 Further, it was argued that au topsy statistics, which dealt with particular groups of those who died, do not reflect total populations of asbestos workers.5 Additional reservations were based on the frequent absence of data regarding From the Division of Thoracic Disease, Department of Medicine, and the Department of Pathology, Mount Sinai Hospital. Read before a joint meeting of the sections on radiology and diseases of the chest and the American College of Chest Physicians at the 112th Annual Meeting of the American Medical Association, Atlantic City, NJ, June 17, 1963. exposure, smoking habits, and personal history, on the size of series, and on inadequate histological verification in some cases. Within the last few years a number of additional problems connected with asbestos exposure have appeared, making clarification and resolution of the foregoing statistical uncertainty a matter of con siderable concern. First, there has been greatly increased use of the various types of asbestos (a five-fold increase in world utilization of this group of minerals, from 500,000 tons to 2,500,000 tons per year in the last 30 years), as well as a greatly in creased number and variety of industrial applica tions of asbestos (over 3,000 such uses now re corded). Second, suspicion has been growing that malignancy associated with asbestos exposure may include neoplasms other than carcinoma of the lung. Thus, a significant relationship has been claimed between diffuse mesothelioma of the pleura and peritoneum and asbestos exposure. Tins communication is concerned with investi gations undertaken to study the following factors: (1) the incidence of deaths due to pulmonary car cinoma among a group of workers exposed to as bestos under United States industrial conditions in the past several decades, (2) whether or not such individuals would also be found to have an increased risk of other neoplasms, and (3) whether such risks would be present in an industry other than the asbestos-producing or asbestos-products industries, with which most reports in the past have been concerned but which would not nec essarily represent the most important areas of as bestos exposure at this time. Further, it was hoped that study of an industry with asbestos exposure of limited extent and intensity would throw some light on the potential problems associated with minimal exposure to asbestos. Materials and Methods Our investigations have been concerned with 1,522 members of the Asbestos Workers Union in the New York metropolitan area, members of New York Local 12 and Newark, NJ, Local 32 of the International Association of Heat and Frost Insu lators and Asbestos Workers. As the full title im plies, these men are insulation workers. Although the union is considered one of the building-trades unions, its members do insulation work in a va riety of industries, including shipbuilding. Called "laggers" in Great Britain, they are often desig nated "pipe coverers," "insulators," or "asbestos workers" in this country. The union is one of the oldest in the country. 142 1964 : vol 188, No 1 ASBESTOS EXPOSURE-SELIKOFF ET AL 23 . on ical >nal ave the onitly (a DUp per inieare hat lay the sen ura sti ffs: `AT- as ms not an her her cts ast ecasted ire me ith ith in ew the SUr in:gh ies pa led igtos ry- l The New York local, as the "Salamander Associa; tion of Boiler and Pipe Felters," was the first union of insulation workers in the United States, It amal gamated with other locals as the current Asbestos ' Workers Union in 1912. The stability of this union ; lias been reflected in the stability of its membersi ship rolls. "Once a pipecoverer, always a pipecov: erer" has been of epidemiological importance to us r and has made this group of-men particularly suit able for the study of long-term effects of asbes{os inhalation. Unlike unskilled workers exposed to asbestos inhalation in poorly paid industries, ...there is little labor turnover among . insulation workers. Accurate employment records are main tained by the union, which has also been con : cemed with health problems in the industry. ! v The trade was badly hit during the depression; ') some men had to drop out and very few were . added during the 1930's. By the end of 1942 the !; union rolls consisted mainly of men with considi; .erable experience, plus a few who joined in 1940, 1941, and 1942. Between 1946 and 1962 union K membership increased substantially, gj. Source of Data.--From union records, a list was prepared of every individual who was a member of either of the metropolitan locals on Dec 31, jU, 1942, or who joined between that date and Dec 31, !> 1962. No one was omitted, whatever his subse quent work history. The 1942 list included 632 fv men; 890 men joined after 1942. |i;v Personal data were obtained from union records, I? and the work history of each man was detailed, p:- including withdrawal from employment (war serY vice, other employment, retirement, illness). These data gave the baseline for calculation of the onset y) and duration of exposure. For members who had |v died, records of the Health and Welfare Fund pro?;}. vided date and place of death. Copies of death certificates were obtained on all but one of them. Autopsy protocols, histological specimens, and hos:'r pital records were obtained and reviewed in those deaths, approximately one half, in which the ter minal illness had occurred in a hospital. ` Statistical Analysis.--Previous studies have sug1] gested that neoplasia associated with asbestosis .seli>' dom occurs until 20 years after first exposure to as ? bestos dust. Therefore, we decided to limit the present analysis to men with such an exposure >;' history. Our complete records cover all members C; of the union (including active and retired rriemii-'l bers, both dead and alive) during the 20-year ` period from Jan 1, 1943, through Dec 31, 1962. However, with few exceptions, the only men with ' a history of 20 years or longer since first exposure : to asbestos were the 632 men on the union rolls as t of Jan 1, 1943. (The exceptions were a few men I who joined the union after Jan 1, 1943, but who , had been employed previously as asbestos workers elsewhere.) Of these 632 men, 255 died before Jan v 1,1963. Table 1.--Man-Years of Experience of 632 Asbestos Workers Exposed to Asbestos Dust 20 Years or Longer Years Age 35-39 ................. ..... 40-44 ................. ..... 45-49................. ..... 50-54 ................. ..... 55-59................. ..... 60-64 ................. ..... 65-69 ................. ..... 70-74 ................. ..... 75-79 ................. ..... 80-84 ....................... 85+ .................... ..... 19431947 85.0 230.5 339.5 391.5 382.0 221.0 139.0 83.0 31.5 5.5 3.5 Totals ................ 1,912.0 19481952 185.0 466.5 324.0 364.0 390.0 341.5 181.0 115.5 70.0 18.5 2.0 2,478.0 19531957 7.0 291.5 530.0 308.0 316.0 344.0 286.0 137.0 70.5 38.5 8.0 2,336.5 19581962 11.0 70.0 314.5 502.5 268.5 255.0 280.0 197.5 75.0 23.5 13.5 2,011.0 Of these 632 men, 339 had been exposed to as bestos dust prior to 1924. In other words, as of Jan 1, 1943, 20 years or longer had elapsed since these 339 men were first exposed. The remaining 293 men reached the 20-years-since-first-exposure point at some time after Jan 1, 1943, and before the end of 1962. The 339 men who were first exposed prior to 1924 were counted in each of the 20 years (or up to the time of death of those who died). The 293 who were first exposed in 1924 or later were counted only after they reached the 20-years-since- . first-exposure point (those who died being dropped at the time of death). When the statistics were completed, we found that we had records covering a total of 8,737.5 man-years of experience of men with a history of 20 years or longer since first exposure to asbestos dust. Of the 8,737.5 man-years, 1912.0 were in the fiveyear period 1943-1947;. 2,478.0 were in the period 1948-1952; 2,336.5 were in the period 1953-1957; and 2,011.0 were in the period 1958-1962. Table 1 shows the age distribution of the man-years in each of these five-year periods. Table 2 shows (1) the average age-specific death rates of all US white males during each of these periods, and (2) the average age-specific death rates from cancer of the lung, pleura, mediastinum, and trachea among US white males during each period, as reported by the US National Office of Vital Statistics. . The man-years were then multiplied by the cor responding reported US death rates to ascertain the expected number of deaths under the null . hypothesis that the death rates of asbestos workers do not differ from death rates of all US white males (both age and date being taken into consid eration). The results are summarized in Table 3. Results Total Deaths--During the first five years (1943 1947) only 28 deaths occurred among, the asbestos workers, whereas 39.7 deaths would have occurred had their age-specific death rates been the same as for all US white males during those years (Ta ble 3). In other words, at the start of the study, the asbestos workers had below average death rates. This is by no means surprising. Indeed, such 142 143 24 ASBESTOS EXPOSURE-SELIKOFF ET AL JAMA, April 6, 19(>4 Table 2.--'Total Deaths and Deaths From Cancer of the Lung, Bronchus, Pleura, Mediastinum, and Trachea per 10,000 White Males per Year _________ 1943-1947________ 1948-1952 ___________ 1953-19571958-1962 Age r Total , -. ^ Lung Cancert 1 Total >r Lung Cancert Total >r Lung Cancert Total " Lung Cancert 35-39 ............... 36 .... 30 .... 26 .... 25 1 40-44 ................ 55 1 48 1 43 1 42 1 45-49 ................ 85 2 78 3 72 3 70 3 50-54 ................ 133 4 124 5 115 6 116 7 55-59 ................ 196 5 189 8 178 10 178 11 60-64 ................ 2957281102761427217 65-69 ............... 435 7 417 li 4l6 17 8 21 70-74 ................ 634 6 605 11 586 16 607 21 75-79 ............... .............. 9776915108781486617 80-84 .......... 1.453 5 1,353 8 1,346 12 1,363 15 85+ ................. 2,422 3 2,162 7 2,017 9. 2,148 11 Death rates as reported annually by the US National Office of Vital Statistics. A five-year average is given here for each period. Average for 1958-1962 is a projection of 1958-1960, since 1961-1962 rates are not yet available. tOeath rates include cancer of the lung, bronchus, pleura, mediastinum, and trachea, assigned to international list code No. 47b-f prior to 1949 and to No. 160-164 thereafter. is almost always found in the first few years of a prospective epidemiological study of this type. The explanation is almost certainly as follows: The 632 men in this analysis were actively employed as as bestos workers in 1942. Since disability from illness or other causes precludes employment in a trade of this type, these men were presumably well (or at least not disabled) at the start of the study pe riod. Almost any group so selected as to exclude the ill and disabled has a lower death rate during the ensuing few years than does the general popu lation, since ill and disabled persons have extreme ly high death rates. A selective effect of this type gradually wears off with time and largely disap pears within five to ten years from the time of in itial selection. During the second five-year period (1948-1952) the death rate of the asbestos workers was slight ly higher than the death rate of all US white males, ie, 54 observed deaths compared with 50.8 ex pected deaths. In later periods, the death rate of the asbestos workers was proportionately higher. For the period 1953-1957, there were 85 observed deaths compared with 56.6 expected deaths, and for the period 1958-1962, there were 88 observed deaths compared with only 54.4 expected deaths. Table 3.--Observed and Expected Number of Deaths Among 632 Asbestos Workers Exposed to Asbestos Dust 20 Years or Longer Cause of Death Years ,------------------- --, Total, 1943- 1948- 1953- 1958- 19431947 1952 1957 1962 1962 Total, all causes ............................ 28 Observed (asbestos workers) Expected (US white males).... 39.7 54 50.8 85 56.6 88 255 54.4 203.5 Total cancer, all sites .................. 13 Observed (asbestos workers) Expected (US white males).... 5.7 17 8.1 26 13.0 39 9.7 95 36.5 Cancer of lung and pleura......... 6 Observed (asbestos workers) Expected (US white males).... 0.8 8 13 18 .45 1.4 2.0 2.4 6.6 Cancer of stomach, colon, and rectum ..................................... 4 4 7 14 29 Observed (asbestos workers) Expected (US white males).... 2.0 2.5 2.6 2.3 9.4 Cancer of all other sites combined ....................................... 3 5 6 7 21 Observed (asbestos workers) Expected (US white males) .... 2.9 4.2 8.4 5.0 20.5 Asbestosis ....................................... 0 1 4 7 12 Observed (asbestos workers) Cancer of the Lung, Pleura, and Trachea.--In each of the four five-year periods, far more deaths from cancer of the lung and pleura occurred among the asbestos workers than would have oc curred had their death rates from these diseases been the same as for all US white males (Table 3). Altogether 45 of the 632 asbestos workers died of cancer of these sites, whereas only 6.6 such deaths would be expected from general US experience. Of these 45 deaths, 42 were recorded as due to bronchogenic carcinoma and 3 to neoplasms of the pleura. The pleural neoplasms were all recorded as mesotheliomas. Thus it was found that the death rate from can cer of the bronchus and pleura was 6.8 times as high among these asbestos workers as in the gen eral US white male population (both age and date being taken into consideration). It may be asked whether the high rate of lung cancer among these asbestos workers could pos sibly be attributed to an unusually large proportion of cigarette smokers among them. We cannot an swer this question directly, since we have not yet been able to ascertain the smoking habits of the men who died. However, the following pieces of evidence indicate that unusual smoking habits can not account for the high death rate from lung can cer among these workers: We have interviewed 320 of the 377 surviving members of the 1942 group. Table 4 gives a sum mary of the smoking habits in this group compared with a sample of men drawn from the general population of 1,121 counties in 25 states.7 The un ion sample is somewhat inadequate since it does not include the men who died and does not in clude all of the present living members of the union. Nevertheless, it shows that a substantial proportion of asbestos workers never smoked ciga rettes regularly. Certainly the 632 men in our analy sis of death rates were not all heavy cigarette smokers. In the general male population, lung-cancer death rates are about ten times as high among cigarette smokers as among nonsmokers; and the 144 I c, 1964 Vol 188, No 1 ASBESTOS EXPOSURE-SELIKOFF ET AL 25 a Table 4.--Smoking Habits of 320 Abestos Workers Exposed to Asbestos Dust 20 Years or Longer Compared With Sample of Men From the General Population Cancerf 1 1 3 7 11 17 21 21 17 15 11 Average b-f prior ra.--ln ieaths airred 'e oceases Ie 3). ed of eaths ence. je to f the rded j'. K-' can is as gendate [ I 1 lung pos- tion an- yet the ! of anan- r f\ ;V: *.y- f f ). ing : imred :ral f an>es in- | he ial ; ;a- ly- Si te t er lg { le I Age 40-49 50-59 60-69 70+ Never Smoked Regularly Asbestos Workers, % 9.3 14.3 20.3 25.5 General Population, % 18.8 19.9 23.6 37.1 Smoked Pipe, Cigar, Never Cigarettes Asbestos Workers, % 4.6 6.1 10.1 11.8 General Population, % 7.5 9.9 16.2 23.9 *Sample of men from general population as reported by Hammond and Garfinkel.7 History of Cigarette Smoking Asbestos Workers, % 86.1 79.6 69.7 62.7 General Population, % 73.7 70.2 60.2 39.0 death rate from lung cancer increases greatly with the amount of cigarette smoking.8 However, a large proportion of all men in the United States have a history of regular cigarette smoking. From data in a prospective study on smoking,8 it may be esti mated that if all men smoked a pack or more of cigarettes a day (ie, if all the nonsmokers, cigar smokers, pipe smokers, and light cigarette smok' efs hid, instead, been heavy cigarette smokers) the lung-cancer death rate would be approximately 3.4 times as high as it is at this time. From this we may conclude that even if all our asbestos workers had smoked a pack or more of cigarettes a day (and, indeed, from our sample we know they did not), and if exposure to asbestos were of no significance, then their lung cancer death rate would have been about 3.4 times as high as the rate in the general US male popula tion. Clearly, the smoking habits of the asbestos workers cannot account for the fact that their lungcancer death rate was 6.8 times as high as that of white males in the general population. Gastrointestinal Cancer.--Rather to our surprise, the death rate from cancer of the stomach and the death rate from cancer of the colon and rectum were higher among the asbestos workers than would be expected from the rates reported for the US white male population, calculated in the same way as for lung cancer. Twelve deaths from gastric cancer occurred among the asbestos workers, as compared with only 4.3 expected. Seventeen deaths from cancer of the colon and rectum occurred among the asbestos workers, as compared with 5.2 expected. Cancer of All Other Sites--The combined death rate from cancer of all sites other than lung and pleura, and stomach, colon, and rectum was not increased. Twenty-one such deaths occurred among asbestos workers, as compared with 20.5 expected. Asbestosis.--Of the 255 deaths, 12 were due to asbestosis (pulmonary insufficiency, cor pulmo nale). The lapsed time from first asbestos exposure to death from asbestosis averaged 45.8 years, with a range of 32 to 59 years. Comment Carcinoma of the Lung.--The results with regard to carcinoma of the lung are clear. Industrial ex posure to asbestos by insulation workers, as stud ied here, residts in a marked increase in the inci dence of cancer of the lung, approximately six to seven times the expected incidence. Altogether, 45 (17.6%) of 255 men with more than 20 years elapsed since the onset of exposure died of cancer of the lung or pleura. These data do not give the "incidence of cancer of the lung in asbestosis." They relate to the spe cific condltinns of 9W investigation: to a group of men with only intermittent exposure to materials ' containing limited amounts (often 2% to 20%) of asbestos under working conditions varying from very dusty, as in extracting old insulation in closed quarters, to those with little dust exposure, as in building construction in open air. Moreover, they relate to the relatively recent past, in a trade with the shorter work week of the strong building trades unions, in an era when industry has been aware of potential asbestos hazard and the working popu lation has had some consciousness of potential risk associated with dust exposure. These data would not necessarily apply to asbestos exposure in other industries, such as the factory production of asbestos products, the asbestos textile industry, etc, where conditions of employment might be quite different. Our results do not contradict the even higher incidence of lung cancer suggested in other studies3; they are merely a shade less strik ing. Diffuse Pleural and Peritoneal MalignancyMesothelioma--Determining the incidence of dif fuse pleural mesothelioma is complicated by the insecurity of its histological verification. While some pathologists will so categorize a high propor tion of diffuse pleural tumors, in the experience of others it is a veiy rare tumor and may be mim icked by anaplastic peripheral carcinoma of the lung and diffuse fibrosarcoma of the pleura. It is difficult to evaluate completely the published re ports of diffuse pleural mesothelioma in asbestosis in the absence of complete details of each case. To the present time, there has been no informa tion concerning the incidence of diffuse pleural mesothelioma in asbestosis, since the published cases are reported without reference to a total pop ulation in which they occur. Nevertheless, the 26 ASBESTOS EXPOSURE--SELIKOFF ET AL JAMA, April G, 1904 growing number of reports of individual cases suggests that these tumors are perhaps becoming relatively frequent complications of asbestos ex posure. Our observations in this series are similarly sug gestive. In three of the 255 deaths among the men who had worked for 20 years or more, the exam ining pathologist considered the death due to dif fuse pleural mesothelioma, and in the two cases in which we have been able to review the histological material, the histological appearance was that of ten so categorized, and asbestos bodies were pres ent. This incidence of more than 1% of deaths from pleural mesothelioma is strikingly high for a tumor which is generally considered to be extreme ly rare. In one case in our series pathological ex amination suggested diffuse peritoneal mesotheli oma. This single experience is too fragmentary for evaluation. Gastrointestinal Carcinoma.--Isolated instances of gastrointestinal carcinoma in the presence of asbestosis have been known, but there have been no data to indicate that these were more than coinci.1 ntal findings. Among the asbestos workers studied here, cancer of the stomach, colon, and rectum was three times as frequent as expected. These data suggest that there may perhaps be an etiological relationship between industrial asbestos exposure and carcinoma of the gastrointestinal tract. Environmental Asbestos Exposure--The recent demonstration, by South African 0 and British * in vestigators of pleural and peritoneal neoplasms among individuals who had chance environmental exposure to asbestos many years before raises the very important question of possible widespread carcinogenic air pollution. The possibility of en vironmental exposure has long been known. Soon after the initial clarification of asbestosis as a clinic entity, Haddow 10 demonstrated asbestos bodies in a man not employed in the industry but living next door to an asbestos factory. This finding was later mirrored in the finding of chronic beryllium dis ease among residents of a community near a beryl lium factory.11 What is new, however, is an appre ciation of the potential extent of the problem. Thomson and associates 12 have reported the fre quent findings of asbestos bodies in the lungs of urban dwellers. Among 6,312 individuals x-rayed in an area about an asbestos mine in Finland, Kiviluoto 13 found 499 cases of pleural calcification of the type characteristically seen among asbestos workers, without obvious cause. In a comparable area without any asbestos mine, no cases were found among 7,101 persons x-rayed. It should be noted that these were not people who worked in the mine--none did--but, rather, were farmers, housewives, and others who lived in the general location. In one subject who came to autopsy, polarized-liglit microscopy demonstrated asbestos fibers in the lung. Similarly, the lung of a cow graz ing near the mine also showed the presence of asbestos. A particular variety of environmental exposure may be of even greater concern. Asbestos exposure in industry will not be limited to the particular craft that utilizes the material. The floating fibers do not respect job classifications. Thus, for ex ample, insulation workers undoubtedly share their exposure with their workmates in other trades; intimate contact with asbestos is possible for elec tricians, plumbers, sheet-metal workers, steamfitters, laborers, carpenters, boiler makers, and fore men; perhaps even the supervising architect should be included. 1 E 100th St, New York 10029 (Dr. Selikoff).- This study was supported by the Health Research Coun cil of the City of New York. Cooperating in this investigation were the executive of ficers of the International Association of Heat and Frost Insulators and Asbestos Workers, Washington, DC, and the officers and membership of the New York and Newark, NJ, locals of this Union. References 1. Lynch, K.M., and Smith, W.A.: Pulmonary Asbestosis: Carcinoma of Lung in Asbesto-Silicosis, Amer J Cancer 24:56-64 (May) 1935. 2. Annual Report of Chief Inspector of Factories for Year 1955, London: Her Majesty's Stationery Office, 1956, cmnd 8, p 206. 3. Doll, R.: Mortality From Lung Cancer in Asbestos Workers, Brit J Industr Med 12:81-86, 1955. 4. Bohlig, H., and Jacob, C.: Neue Gesichtspunkte fiber den Lungeakrebs der Asbestarbeiter, Deutsch Med Wschr 81:231-233 (Feb 17) 1956. 5. Braun, D.C., and Truan, T.D.: Epidemiological Study of Lung Cancer in Asbestos Miners, AMA Arch Industr Health 17:634-653 (June) 1958. 6. Wagner, J.C.; Sleggs, C.A.; and Marchand, P.: Diffuse Pleural Mesothelioma and Asbestos Exposure in North Western Cape Province, Brit ] Industr Med 17:260-271, 1960. 7. Hammond, E.C., and Garfinkel, L.: Smoking Habits of Men and Women, J Nat Cancer Inst 27:419-442 (Aug) 1961. 8. Hammond, E.C., and Horn, D.: Smoking and Death Rates: Report on Forty-Four Months of Follow-up of 187, 783 Men. I. Total Mortality; II. Death Rates by Cause, JAMA 166:1159-1172 (March 8); 1294-1308 (March 15) 1958. 9. McCaughey, W.T.E.; Wade, O.L.; and Elmes, P.C.: Exposure to Asbestos Dust and Diffuse Pleural Mesothelio mas, Brit Med ] 2:1397 (Nov 24) 1962. 10. Haddow, A.C., in Report of Annual Meeting of British Medical Association, Manchester, 1929, Lancet 2:230-231 (Aug 3) 1929. 11. Chesner, C.: Chronic Pulmonary Granulomatosis in Residents of Community Near Beryllium Plant: Three Autopsied Cases, Ann Intern Med 32:1028-1048 (June) 1950. 12. Thomson, J.G.; Kaschula, R.O.C.; and MacDonald, R.R.: Asbestos as Modem Urban Hazard, S Afr Med J 37:77-81 (Jan 19) 1963. 13. Kiviluoto, R.: Pleural Calcification as Roentgenologic Sign of Non-Occupational Endemic Anthophyllite-Asbestosis, Acta Radiol Suppl 194, pp 1-67, 1960. 146