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i/ 106 PLAINTIFF'S EXHIBIT RECEIVED NOV 81979 K. w. NEi:::; Asbestos; Exposure, Smoking, and Neoplas Irving J. Sclikofl, MD: E. Cuyler Hammond, Sri): and Jacob Clnirg, MD Asbestos insulation workers, as a group, have a high due to chance, the number of such deaths being risk of dying of bronchogenic carcinoma (about seven or small. During the latter part of the study, we ob eight times expected). We have observed 370 such work* tained information on the smoking habits ol most men from Jan 1, 1963 to April 30, 1967. Our findings of the survivors, but we could not obtain reliable indicate that asbestos exposure alone is not the entire information on the smoking habits of those who explanation. QL87 noncigarette smokers, none died of had died at an earlier date. Therefore, we could bronchogenic carcinoma. Of 283 workmen with a history not at that time investigate death rates in rela of regular cigarette smoking, 24 died of bronchogenic tion to smoking habits and exposure to asbestos carcinoma, although only three were expected to die of dust which were considered both separately and this disease. Calculations suggest that asbestos workers jointly. who smoke have about 92 times the risk of dying of There is abundant evidence that cigarette smok bronchogenic carcinoma as men who neither work with ing leads to a high rate of death from lung cancer asbestos nor smoke cigarettes. We conclude that asbestos in the absence of occupational exposure to asbestos exposure should be minimized, that asbestos workers who dust.1'* Our findings outlined above suggested (but do not smoke should never start, and that those now did not prove) that exposure to asbestos dust may smoking should stop immediately. lead to a high rate of death from lung cancer in the absence of cigarette smoking. If the latter be n 1964, we reported on deaths occurring between so, then the combined effect of both types of ex I Jan 1, 1943, and Dec 31, 1962, among 632 posure might or might not be equal to or greater members of the International Association of Heat than the sum of the two effects. On the other hand, and Frost Insulators and Asbestos Workers.1 All it was possible that exposure to asbestos dust in of these men had been occupationally exposed to creases the risk of lung cancer among cigarette asbestos dust for many years. Their death rate smokers but does not lead to lung cancer among from lung cancer was found to be 6.8 times as high nonsmokers. as that reported for the general white male popu The present study was undertaken primarily lation of the United States during the same years, to investigate these possibilities. In addition, we> with age taken into consideration. Three of the wished to obtain more information on the occur men-died of diffuse pleural mesothelioma and one rence of mesothelioma and gastrointestinal cancer died of a neoplasm histologically suggestive of peri among asbestos workers. toneal mesothelioma. This was of interest since mesothelioma is a very rare disease in the general population but is reported to be associated with Material From records of New York Local 12 and Newark, exposure to asbestos dust.1 In addition, their death rate from cancer of the stomach, colon, and rectum was higher than expected; but this may have been From (he Department of Community Medicine* Mount Sinai School of Medicine (Drs. Sclikofl and Churg), and the Dcpnrtment of Cpidemiotogy and Statistics, American Cancer Society (Dr. Hammond), New York. Read before a joint meeting of the Section on Diseases of the Chest with the Section on Preventive Medicine and the American College of Chest Phyiimivt at the HGth annual convention of the American Medical Association, AtUnlir City, NJ, Juno 19, lfK77. Itoprint requests to Mount Sinni School of Medicine, 100th Street and Fifth Avenue, New York 10029 (Dr. Selikoff). N-J, Local 32 of the International Association of Heat and Frost Insulators and Asbestos Workers, a list was made of every man who was a member of cither one of these locals on Dec 31, 1942, oi who joined between that date and Dec 31, 1962. No one was omitted regardless of his subsequent work history. Personnel data from union records indicated that of the 632 on the union rolls on Jan 1, 1943, 33S of the men had first been occupationally exposed to asbestos dust prior to 1922, and an additional 104 JAMA, April 8. 1968 Vol 204. No 1 y ASARCO ALV 0002148 ASBESTOS EXPOSURE-SEUKOFF ET AL 107. 83 men had first been ex* Table 1.--Subjects Classified by Age as of Jan 1,1963, and by Years From First Occupational v--d between the be- Exposure to Asbestos Oust up to Jan 1,1963 g of 1923 and the mu of 1942. All of these sen were successfully traced through Dec 31, 1962, and 262 of them nre found to have died op to that time. Of the 262 deaths, seven oc* cuned prior to the 20th anniversary of the man's fist exposure to asbestos Age, Yr 35-39 40-44 4549 50-54 55-59 60-64 6569 70-74 75-79 0-64 Total Total No. of Sub|ect* 2 13 32 109 60 42 49 38 21 4 370 r 20-24 2 12 17 . . > ... . No. of Years Since First Exposure to Asbestos 25-29 1 2 1 1 ,1,, ... ... 7 30-34 ... .. 13 80 16 3 1 . ... 113 35-39 . ... ... 28 34 11 10 3 ... 36 4044 ... .. ... 8 19 18 12 1 1 59 4549 .. ... . 1 8 18 6 5 1 39 No. Of 50+ 52 Mo* ... . ...... 1 2 18 14 u ... 16 2 17 17 IS 15 8 23 36 94 dost and 255 occurred after the 20th anniveraaiy. Thus, of the 632 men, 370 were still living on Jan 1, 1963. These 370 men were the subjects of the pres ent investigation. Table 1 shows their age distribu tion as of Jan 1, 1963, and the lapsed time from first exposure up to that date. All of them have been traced, and 94 of Table 2.--Subjects Classified by Age and by Smoking Habits on or about Jan 1,1963 35-39 4044 45-49 50-54 55-59 60-64 65-69 70-74 75-79 30-84 ToUt Tout No, 2 13 32 109 60 42 49 38 21 4 370 Smoked Regularly 1 2 2 12 6 7 6 7 3 2 48 Cigar Only ... ... 1 6 5 4 8 7 7 1 39 cigarette Smokers* 1 2 5 26 16 15 17 12 6 1 101 Current Cigarette Smokers* 1-9 o Day ... ...... .3 .. i. i ... ... 5 10-19 o Oay ... ... ... 5 ..3. 4 4 1 ... 17 20-39 o Day ... 5 12 33 20 a 9 4 3 -- 97 40+ o..O.ay 4 12 24 10 4 5 3 1 -- 63 them were found to have (Bed during the four-year Mnctudes cigarette smokers who also smoked pipes or cigars. TfC * four-month interval from Jan 1, 1963, to April 101 were excigarette smokers, five currently smoked .967. one to nine cigarettes a day, 17 smoked 10 to 19 Beginning in October 1962, we made arrange cigarettes a day, 97 smoked 20 to 39 cigarettes a ments to examine these men periodically, once day, and 63 smoked 40 or more cigarettes a day. every six to twelve months; the interval depended The smoking habits of the 370 subjects were cpon age and physical condition. The examinations compared with the smoking habits of a large num indude chest x-ray films as well as physical ex- ber of men selected from the general population.1 emination and cover past and present smoking There were proportionally more cigarette smokers habits, occupational history, medical history, and nmnnyr the ayfisubiects tfian were_jound in the current physical complaints. Altogether, we have gpnnral pnpnlaHnn samnle; age wastaken Into examined 338 (91.4 ) of the men at least once consideration. and have repeatedly examined most of those who Causes of Death.--A copy of the death certificate are still living. was obtained for each of the 94 deaths. In addi Information on smoking habits was obtained by tion. we examined hospital records, postmortem personal interview with the 338 men who were ex findings (41 cases), as wen as tne surgical and amined. Of the 32 men who. were not examined, pathologic reports wnen surgery was pertorme<T(39 . six told us their smoking habits by telephone and cases). We also reexamined histologic specimens. r five gave us the information by maiL The local It was found that the death certificate was inac union secretaries (who personally knew these men curate in 14 instances. However, this did not alter" welt) ascertained the smoking habits of 18 men, the picture as muen as might have been expected ' and family members supplied the information on since there were several compensating errors. For ' the remaining three men. This accounts for all of example, in one instance the death certificate in . the 370 men. Table 2 shows their smoking habits dicated bronchogenic carcinoma as the cause of < oner about Jan 1, 1963, the men being classified death while a review of the histologic specimen by their ages on that date, even though some showed that death was due to pleural mesothe changed their smoking habits between 1963 and lioma; but in another instance exactly the reverse i 1967. was found. Likewise, review in one instance re - Of the 370 men, 48 never smoked regularly, 39 sulted in changing the reported cause of death } ked or had smoked pipes or cigars but never from bronchogenic carcinoma to cancer of the , .jked cigarettes regularly, and 283 had smoked stomach with metastasis to the lungs while review cigarettes regularly. Some of those with history of in another instance resulted in exactly the oposite f\" cigarette smoking also smoked pipes, or cigars. Of change. The 94 deaths were ascribed to the follow [. the 283 with a history of regular cigarette smoking. ing causes: bronchogenic carcinoma, 24; pleural I JAMA. April 8. 1968 Vol 204. No 2 105 ASARCO ALV 0002149 108 ASBESTOS EXPOSURE-SELIKOFF ET AL Table 3.--Observed and Expected Number of Deaths Among 370 Asbestos Workers During the 52*Month Period white males of various ages during the year 1964 as reported by the National Center for Health Sta j 4 Cium of Death Observed Expected Deaths Deaths* tistics. These percentages were then standardized for age according to the age distribution at time Total, eancer (all sit**) 49 8.6 of the 47.5 expected deaths. The results are shown Cancer ot lung, plaura. bronchus. |t and trachea Bronchogenic carcinoma < Pleural mesothelioma Peritoneal mesothelioma 27 2.3 in Table 3. 24 t Expected vs Observed Deaths.--As shown in 3 7 t t Table 3, there were 94 observed deaths (ie, 94 of 1 Cancer of stomach 3 0-6 the 370 asbestos workers died) as compared with 1 Cancar of colon and rectum ; Cancer of all other sites combined JT Asbestosis 5 7 1.2 4.5 47.5 deaths expected on the basis of the age-specific 15 ... death rates of all white males in the United States Heart and circulatory disease including 'j stroke Ail other causes of death 22 28.5 in 1964. Thus, there were 94 minus 47.5 - 46.5 B 10.4 excess deaths. The excess deaths were due to bron 4 Total, all cauaas 94 47.5 chogenic carcinoma, mesothelioma of the pleura *Based upon US mortality date disregarding smoking habits. * tUnitad States data not available, but figure should bo only slightly and peritoneum, asbestosis, and cancer of the stomach, colon, and rectum. ^Vunitod^SUtos data not avaitabla, but thoso art raro causes of death In gonoral population. Cancer o/ Lung, Pleura, and Trachea.--In pub lished mortality data for the United States show _^*mesothelioma7three) peritoneal mesothelioma, sev- ing deaths each year from various causes by age, en; cancer oi tne colon, tour; cancer of the rectum, sex, and race, the following diseases are combined: "one; cancer of the stomach, three; cancer of the cancer of the lung (including sarcoma of the lung), pancreas, two; cancer of buccal cavity and pharynx, cancer of the bronchus, cancer of the pleura, and two; cancer of bladder, one: cancer of undeter- cancer of the trachea. For this group of diseases, mined primary site, two; (asbestosis, 15;)cor pul there were 27 observed deaths and only 2.3 ex monale, one; comary heart disease, 17; congestive pected deaths, a ratio of nearly 12 to 1. heart failure, one; cerebral vascular lesion, two; It is well known that, for the United States as aortic aneurysm, one; cirrhosis of the liver, three; p. whole, all except a very few of the deaths re- bronchopneumonia, one; encephalopathy, one; acute pancreatitis, one; Wegener's granulomatosis, Echhoiortgeednicinctahrecincoommab.inTehdusc,atietgmorayy are be due to broiv assumed that t ,M one; and accidental fall, one. there were close to 2.3 expected deaths from this Expected Deaths.--Fat purposes of comparison, cause as compared with 24 observed deaths, a ratio we wished to ascertain how many of the 370 sub of over 10 to 1. j_ jects would have died during the 52-month period Mesothelioma^Ten of the 94 observed deaens ~ i i M (Jan 1,1963, to April 30,1967) if their age-specific fCCere due to mesothelioma,/Three were due to death rates had been exactly the same as for the pleuiulTTieiOthelioma, and seven were due to peri ] general white male population ofthe United States. toneal mesotheliomas. This is such a rare disease /Tor this purpose, we made use ot the Unitea states j that if the 370 subjects had been selected as a -I | 1964 life table for white males; this provided the/ random sample from the general population, one Tnost stable basis tor comparison, it snould be would not have expected any of them to die of noted that for white males total death rates and mesothelioma within a period of 52 months. death rates from respiratory cancer were slightly All three of the men who died of pleural mes<P| higher in the industrial states of New York and thelioma had a history of regular cigarette smoking. I . New Jersey than in the United States as a whole.*'7 Of the seven who died of peritoneal mesothelioma, I ;1 On the other hand, respiratory cancer death rates in one never smoked regularly, one smoked only pipes I 3; : white men aged 20 to 64 are reported to be a trifle and cigars, and five had a history of regular ciga lower than average among laborers, not elsewhere rette smoking. __ classified employed in construction work.* Cancer of StomachColon, and Rectum.--In our* i From the life table we determined for each of the earlier study of asbestos workers,1 there were more i J* 370 men the probability of his dying within a pe deaths than expected from cancer of the stomach, ; riod of 52 months, considering his age on Jan 1, colon, and rectum (9.4 expected, 29 observed). As I. 1963, and assuming that the life table probability compared with a total of 1.8 expected deaths from \ ,, applied to him. Summing these probabilities for the these causes, there were eight observed deaths in 370 men yielded an estimate of the "expected" this study, due to cancer of the following sites: number of deaths under the null hypothesis that stomach, three; colon, four; and rectum, one. Al the age-specific death rates of these asbestos work though this bears out our earlier findings, the num ers are the same as for United States white males ber of deaths from these causes was so small that in general The computation indicated that 47.5 we still refrain from drawing any conclusion at deaths would have been expected. this time. ~ Next, we wished to estimate the expected num Asbestosis.-Asbestosis accounted for 15 of the ber of deaths from each of several causes. For this, 94 deaths. While it is not surprising that deaths we made use of the percentage distribution of from this disease occur among men exposed to deaths by cause of death among United States asbestos dust, attention must be called to the fact 10S JAMA, April 8. 1968 Vol 204. No 2 ..liX -T laewwwvgi! ASARCO ALV 0002150 ASBESTOS EXPOSURE--SEUKOFF ET At 109 . that these subjects were primarily insulation work- Table 4.--Estimated Number of Lung Cancer Deaths Expected to Occur During a Period of 52 Months per 10,000 Men Living at the Start of Period; by Age and by Smoking Habits* While all of them ^re occupationally ex posed to asbestos dust, their degree of exposure - was light as compared Ajtt, Tr (Jan 1,1963) 35-39 40-44 45-49 Never Smoked Regularly 0 2 2 np, Cigar Only . ...t 2 Exctgarette Smokeret 5 71 10 1-9 Day ... Current Cigarette Smokerat 1019 a ..D..a..y ... 20-39 ,O,a,y 15 39 40+ a .D.a.y 15 46 with the degree of exposure of asbestos miners, processors, and weavers 50-54 55 59 60-64 fiscs 7 6 16 14 12 15 31 32 22 28 44 69 90. 53 \ * 9i 117 185 . 71 80 190 256 ...97 157 305 350* ' in earlier times. Bronchogenic Card- 70-74 75-79 6064 12 26 25 52 53 32 100 100 148 1.0.3. ... 206 1.8.5. 288 341 ... 450* 3.2.9. . noma.--Bronchogenic carv'rinoma accounted for 24 - deaths while only about 2.3 were expected on the Bated upon data from a prospective study with adjustment for US mortality experience. tCUipses in..d...ic...a..t.e....r.a..t..e..s...o..m....i.t.t.e...d...f..o..r...c..a..t.e...g..ories with no su.b..j.e..c..t.s....i.n....t.h..i.s....s..t.u...d.y. nSeeet Tfaabblle 2. {includes cigarette tmokers who also smoked pipe or cigar. Men with history of enfjr cigarette smoking have higher lung cancar ratal than mown hart. |Rata* obtained by smoothing the data. basis of general United States mortality data for divided into many five-year age groups, some of the white males. However, as previously mentioned, subgroups contained only a small number of men. evidence at hand suggests that there were propor In consequence, the lung cancer death rate was tionally somewhat more cigarette smokers among statistically unstable in some of the very small sub : the 370 subjects than among white males in the groups. In three instances where the observed rate : United States as a whole, age being taken into in a small subgroup appeared to be badly out of consideration. This might have partially accounted line, we arbitrarily made an adjustment to bring it for the high bronchogenic carcinoma death rate of more into line with adjacent figures in the table. the subjects. For this and other reasons we made These adjusted figures which are indicated with estimates of the expected number of bronchogenic symbols in Table 4 carry very little weight in the carcinoma deaths, the smoking habits of the men final calculation. All of the rates were then ad being taken into consideration. This was done as justed as follows: follows: Lung cancer death rates in the United States *' Data are available on lung cancer deaths in re- have risen steadily year by year and were higher ition to the smoking habits of 440,000 men en- in 1964 than during the period 1960 to 1964 as a . rolled by American Cancer Society volunteers in whole. Furthermore, in the study described above, a prospective epidemiological study between Oc- we avoided enrolling seriously ill people and, as of tober 1959 and March 1960 and traced through the cut-off date for preparing the computer tape, Sept 30,1964. Causes of death were ascertained from we had not yet received death certificates for all i death certificates, but whenever cancer was men of the men now known to have died during the tioned on a death certificate inquiry was made of specified period of time. For these reasons, lung the physician who signed the certificate. In case cancer death rates in the study population were of disagreement between the two sources of infor- appreciably lower than those reported for white mation, the physician's statement was accepted. males in JhaJLIpited States in 1964. To compensate For the purpose at hand, we only made use of data for this, we raisea me rate ot earh individual smok covering the 52-month period beginning on June 1, ing category so that the total King ranner death 1960, and ending on Sept 30, 1964. The number of rate (disregarding smoking habits) in each five- .. lung cancer deaths occurring during the 52-month ygar age group w"ld th-f period was divided by the number of men alive at United States white males (based upon the 1964 r e / the beginning of the period. This was done by fiveyear age groups for men in each of the following smoking categories: (1) never smoked regularly lire table and the 1964 distribution of deaths by causes of death). The results of these computations are shown in Table 4. (It should be noted that W s .- (nonsmokers and occasional smokers being com- Table 4 shows only such rates as were required for bined); (2) history of regular pipe or cigar smok- further calculations.) .1 n ' ing, past or present, but never smoked cigarettes The rates shown in Table 4 were then applied to regularly; (3) excigarette smokers (including those the number of asbestos workers shown in each of who had smoked or currently smoked pipes or the corresponding internal cells of Table 2. This . cigars); and (4) current regular cigarette smokers yielded an estimate of the number of lung cancer t t - (including those who also had smoked or currently smoked pipes or cigars). The last of these cate. gories was further divided by current number of deaths expected to occur during a 52-month period among the 370 asbestos workers classified by their . smoking habits. By ''expected" number, we here e cigarettes smoked per day: (4a) one to nine ciga mean an estimate of the number ot lung cancer rettes a day; (4b) 10 to 19 cigarettes a day; (4c) deaths which would have occurred under the null s 20 to 39 cigarettes a day; and (4d) 40 or more hypothesis that asbestos workers do not differ from D cigarettes a day. Since the men were divided into other men in respect to their lung cancer death seven groups by smoking habits and further sub- rates, both age and smoking habits being taTjgn- - JAMA. April 8.1968 Vol 204. No 2 f 107 ASARCO ALV 0002151 !*' < ' *! L: / i .1? t t ! 4 *:t y;i 1 ; * ' ii : *t *. ! no ASBESTOS EXPOSURE-SELIKOFF ET AU Table 5.--Observed and Expected Bronchogenic Carcinoma Deaths by Smoking Habits* for 370 Asbestos Workers Smoking Habits Never smoked regularly History of pipe, cigar smoking only History of regular cigarette smokingt Observed Deaths 0 0 24 Expected Deaths 005 0.13 2-98 Total 24 3.16 *8ased upon data In Table 2 and Table 4. tlndudes cigarette smoker* who also smoked pipe or agar. Table 6.--Expected and Observed Deaths Among 632 Asbes tos Workers Exposed to Asbesto Dust 20 years or Longer Tot.l d.atha: *11 causa* Expected Observed Total cancer all site* Expectad Observed Cancer of lung, trachea, pleura Expected Observed Ca near of stomach, colon, nctum Expected Observed Cancer all other sites combined Expected Observed Asbestosis Expected Observed AU other causes Expected Observed 1943-1962 203.5 2SS 36-5 95 Total 1963-1967 1943-1967 47.5 94 8.6 49 251 349 ___ 45.1 144 6.5 45 23 27 8.9 72 9.4 29 1.8 1U 8 37 20.5 21 4.5 14 25 35 00 12 ' 15 Q 27 167 38.9 2054 148 30 178 into consideration. The results are summarized in Table 5 which showB the expected and observed number of lung cancer deaths in each of three smoking categories. Taking smoking habits as well as age into con sideration (Table 5) a total of 3.2 bronchogenic carcinoma deaths were expected whereas taking only age into consideration 2.3 deaths were ex pected from this cause (Table 3). Thus, perhaps one of the excess bronchogenic carcinoma deaths might be attributed to the fact that there appear to have heen proportionally somewhat more ciea7pfra~gmr>lfprs among thaJi?!,) subjects than, among* men 'of the same ages in the general population. The following statements are based upon the data shown in Table 5. Twenty-four deaths from bronchogenic carcinoma occurred among the 370 subjects compared with only 3.16 expected, a ratio of about 7.6 to 1. This is slightly higher than found in our earlier study which indicated a ratio of 6.8 to 1 (not taking smoking habits into considera tion). It should be noted in this connection that the 370 subjects in this study had been exposed to asbestos dust somewhat longer than the subjects of our previous study (the present 370 subjects are survivors as of Jan 1, 1963, of subjects in the previous study). Of the subjects who never smoked regularly and those who smoked only pipes or cigars, none died of bronchogenic carcinoma whereas 0.18 of. these men were expected to die of lung cancer. This sug gests that exposure to asbestos dust does not in crease the risk of bronchogenic carcinoma among men who never smoked cigarettes regularly. How ever, considering the small number of such subjects in this study, we only conclude that exposure to asbestos dust does not greatly increase the risk of bronchogenic carcinoma among men who never smoked cigarettes regularly. Twenty-four of the men with a history of regular cigarette smoking died of bronchogenic carcinoma whereas only 2.98 were expected to die of it, a ratio of 8.05 to 1. From this it appears that exposure to asbestos dust greatly increases the risk of lung cancer among cigarette smokers. Now we may ask how greatly is the risk of bron chogenic carcinoma increased by the combined ef fects of cigarette smoking and exposure to asbestos dust. To answer this question, we applied rates shown in Table 4 for nonasbestos workers who never smoked regularly to the number of subjects with a history of regular cigarette smoking as shown in Table 2. This indicated that only 0.26 of the subjects with a history of regular cigarette smoking would have been expected to die of bronchogenic carcinoma if they had never smoked regularly and had never been occupationally exposed to asbestos dust. Since 24 of them actually died of this cause, the ratio of observed to expected deaths is 92 to 1 . (ie, 24 divided by 0.26-92). This appears to in-, dicate that cigarette smoking plus occupational exposure to asbestos dust increases the risk of bronchogenic carcinoma by a factor in the order of magnitude of_92 to 1. It should be noted that this' estimate does not take current amount of cigarette smoking lulu HOhsiderationi Comparison With Earlier Findings.--As explained, we started with a cohort of 632 asbestos insulation workers, the entire membership of the union locals on Jan 1, 1943. We have now traced each man through April 30,1967. Table 6 shows the observed and expected number of deaths for each of two periods (the first, 1943 to 1962, being previously reported') and for the entire period. In respect to respiratory cancer (lung, trachea, and pleura) and in respect to cancer of the stomach, colon, and rectum, the findings in the two periods are in close agreement Comment The increased risk of neoplasia (mainly broncho genic carcinoma and mesothelioma) among insula tion workers reported here should be evaluated in the knowledge that these men have comparatively light exposure as asbestos trades go. Primarily em i ployed in construction work, many of the materials they use contain little or no asbestos and others have only 5% to 15%. Conditions of work vary; these men often work outdoors unlike asbestos operators in factory work. Comparatively few dustexposure surveys have been made in this trade but their results have generally been within the 5 mil lion particles per cubic foot permissible limits cur rently accepted by the American Conference of Governmental Industrial Hygienists.* '0 Nor have 108 I JAMA. April 8. 1968 Vol 204. No 2 ASARCO ALV 0002152 % ASBESTOS EXPOSURE-SEUKOFF ET AU 111 k'additional potentially carcinogenic substances been ! ; identified among the other materials used.,B Heavier or even lighter exposure may result in erent degrees of risk of neoplasia. Heavy factory i ' exposure in the past has in some instances resulted ; \ in considerable lung cancer risk.11 In others, para doxically, little lung cancer was seen because as. bestosis was so common and so severe as to cause death of the exposed workers before they could live long enough to develop lung cancer. Once exposure l was reduced by improved industrial hygiene practices, early death from asbestosis sharply dimin'ished and lung cancer became common.1* In any case, heavy exposure is not likely to be i the most important problem in the future, unless there be sheer carelessness or unconcern. Rather, flight exposure, similar to that in insulation work, will be much more common, both in direct asbestos -"working trades and as the result of indirect occupational exposure, as in the construction and ship building industries. There is another type of "light exposure" which -may affect many more people than those industrial:' ly exposed. In the past several years, it has been >' demonstrated that asbestos bodies can be found in Jthe lungs of 25% to 50% of adults examined at autopsy in large cities, such as Belfast, Northern -'Ireland, Capetown, Republic of South Africa,, t'-Miami, Fla, Pittsburgh, and Montreal. This is '-presumably due to "asbestos air pollution" by 1 *vers derived from industrial "spillover" (as dust ^ m construction sites or factory wastes) or from >end-produet use. Such community asbestos air > pollution may be important since there is already - evidence that in certain circumstances, as living V within half mile of an asbestos plant or in the - household of an asbestos worker, intimate environ.-mental contamination can be associated with some - risk of mesothelioma.1* What is not now known is x whether the minimal amounts inhaled by the general public carry a similar risk.1* | ^ Nor do we know whether inhalation of the very Ismail amounts of asbestos present in the air of some | '^communities is associated with a special lung .^cancer risk in cigarette smokers (or, conversely, * whether cigarette smoking makes the inhalation of : very small amounts of asbestos particularly hazardbus). It will be important to ascertain whether such ' cocarcinogenic or potentiating or precipitating rela^tionships exist because, with the rapid growth of ^-asbestos use (500,000 tons per year world produc- ytion in 1930 has risen to over 4,000,000 tons per - year now), it may be difficult for cigarette smokers .ito avoid inhaling air contaminated with asbestos, v'j It may not be easy to unravel the interrelationf ships which might exist between community as.ibestos air pollution and cigarette smoking. Both asbestos exposure and cigarette smoking have a ^-lapsed period between onset of exposure and ,, .urrence of neoplasia, yet for current smokers 'V these two exposures may not have begun simulta neously; there was much less asbestos used 20 to .V . JAMA, April 8. 19S8 Vol 204, No 2 40 years ago. Youngsters who start smoking now have a much greater chance of having both ex posures simultaneously. Significance of Findings for Asbestos Workers.-- The import of the data reported here seems clear. There is an extraordinary risk of developing and dying from lung cancer for asbestos workers who smoke cigarettes regularly. In the group studied, the combination of asbestos exposure and cigarette smoking increased the risk approximately 90 times compared with men who neither work with asbestos nor smoke! Of 283 asbestos workers who had a history of cigarette smoking, 78 died within a period of 52 months whereas only 32.4 would have been ex pected to die within that length of time if their age specific death rates had been the same as for the general white male population of the United States. Of the 78 deaths, 24 (31%) were due to broncho genic carcinoma. It is estimated that if these men had smoked cigarettes but had not been exposed to asbestos dust, only 2.98 would have died of bron chogenic carcinoma within the same length of time. If they had neither smoked nor been exposed to asbestos dust, only 0.26 would have been expected to die of the disease within a period of 52 months. Of 87 asbestos workers who never smoked ciga rettes regularly, none died of lung cancer within the 52-month period (although three died of asbestosis and one died of peritoneal mesothelioma). This finding, being based upon the experience of only 87 men, does not prove that exposure to asbestos dust has no influence on the risk of lung cancer v among nonsmokers. However, it suggests that ex posure to asbestos dust does not lead to an ex- I tremely high risk of lung cancer among nonsmokers. J The conclusions are evident: 1. Occupational exposure to asbestos dust should be reduced to as low a level as possible; but there may be an irreducible minimum level if asbestos, a very useful material, is to be used at all. Such reduction in exposure will benefit asbestos workers of the future. However, we are also concerned with workers who have already been exposed at signifi' cant levels for many years. Asbestos fibers will re main in their tissues for the remainder of their lives. 2. All people incur a great increase in risk of lung cancer if they smoke cigarettes; for asbestos work ers the increase in risk is tremendous. Asbestos workers who do not now smoke cigarettes should never begin. Those who do smoke, should stop immediately. We may hope that the decrease in risk which results from cessation of smoking among the general public* will be the good fortune of the asbestos workers as well. This investigation was supported by the Health Research Coun cil of the City of New York. References 1. Selikoff, U.; Churg, J.; and Hammond, E.C.: Asbestos Ex posure and Neoplasia, JAMA 188:22-26 (April 6) 1964. 2. Selikoff, 1J.; Churg, J.; and Hammond, E.C.: Relation Be tween Exposure to Asbestos and Mesothelioma, New Eng JMed 272:560-565 (March.18) 1965. i ASARCO ALV 0002153 1 -t -I /i ) :t ..ii I .v 1 r. 'A s- . 1 112 ASBESTOS EXPOSURE--SEUKOFF ET AL 3. Hzmmond. E.C.: "Smoking in Relation to the Death Rates of 1.000,000 Men and Women," in Epidemiological Study ol Canetr end Other Chronic Diseases, Betheade. Md: National Cancer Institute. 1966, monograph 19, pp 127<204. 4. Smoking end Health. Report of the Advisory Committee to the Surgeon General of the Public Health Service, publication 1103, US Dept of Health, Education, and Welfare. 1964. 5. Hammond. E.C, and Garfinkel. L.: Changes in Cigarette Smoking 1959-1965. Amer J Public Health 56:30-45 <Jan) 1968. 6. Vital Statistic* ol the United State*. 1960, part A. US Dept of Health, Education, and Welfare. 1963, vol 2. 7. Death Rate* From Malignant Neoplasm*. 1960. Public Health Service, publication 1113, US Dept of Health, Education, and Welfare, 1963. 8. Mortality by Occupation and Cause ol Death. Public Health Service. US Dept of Health, Education, and Welfare, Vital Sta tistics Division, Vital Statistics--Special Reports, 53:323 (Sept) 'I 1963. ,y 9. Fleischer, W.E,, et al: A Health Survey of Pipe-Covering Operations in Constructing Naval Vessels, J Industr Hyg Toxic ' 28.-9-16 (Jan) 1946. 10. Keane, W.T, and Zavon, M.R.: Occupational Hazards ef Pipe Insulators. Arch Environ Health 13:171-178 (Aug) 1966. 11. Doll. R.: Mortality From Lung Cancer in Asbestos Workers, : Brit J Industr Med 12.81-86 (April) 1955. 1 12. Jacob. G, and Anspach, M.: Pulmonary Neoplaaia Among Dresden Asbestos Workers, Ann NY Acad Sc 133:536-548 (Dee 1 31) 1965. ;. 13. Newhouse, M.L- and Thompson, H.: Mesothelioma ef Pleura and Peritoneum Following Exposure to Asbestos in ths ' London Area. Brit J Industr Med22:261-269 (Oct) 1965. .i 14. SelikofI, U, et al:Asbeatosis andNeoplasia,Amer J Med ' 42:487-496 (April) 1967. Many, possibly most, of the words in the dictionary stand there as representatives of a whole family of forms. Not even the timidest of the linguistically timid will run to the dictionary for encouragement when, for instance, they want to refer to a spell of "hiccuping," provided they are certain that Webster does know "to hiccup." All the tense forms, the participles, the gerunds are assumed to be authorized by implication the moment the infinitive is known to exist The plurals of nouns are similarly taken for granted, and the forms of comparison and the adverbial forms of adjectives. This phenomenon is generally covered by the assertion that a dictionary is not a grammar and that each individual entry in a dictionary stands simultaneously for all its grammatically possible forms. (For details, consult your grammar.) But is a gerund a grammatical form? Or is it a suffix-derived noun? I am not really looking for an answer. I ask those questions to suggest that the dividing line between grammatical form and derived neologism is both hard to de fine and artificial. If I distinguish--among men--the "hunting" from the "hunted," I have done no more than form (grammatically) two nouns from two adjectives which are forms (grammatically) implied in the existence of "to hunt." But if "hunting" is implied, why not "hunter"? Why not "huntee" and "huntable" and "huntabilize"? The question of when a new word is a new word and when it is merely an "im plied" form of a conventional term is indeed more complex than is grossly ap parent Take "dehairability" as an example. Can I claim the word is implied in the existence of "hair," or must I assume the responsibility for having spawned a monster? Or take "unequivocably," which indeed was the starting point of all this rea soning and wondering, for it was spotted as a bold neologism in JAMA in the sentence, "Research at the Public Health Service Hospital at Lexington, Ky, has unequivocably proven that methadone has all of the euphoric properties of morphine...." Now, clearly, the adverb "unequivocably" is grammatically implied in the ad jective "unequivocable," and this in turn is implied--grammatically of semi-gram matically or otherwise--in "equivocable." If we grant further that formations in "-able" of "-ible" are likewise legitimate without special dispensation, we shall conclude that "unequivocably" is in no sense a bold departure since "to equivo cate" is a firmly established, standard English word. But there is a hitch and a flaw in the argument "To equivocate" means "to use ambiguous language" and (by extension) "to render ambiguous." Hence, "equivocable" can only suggest the trait of "being apt or able to be made ambig uous," and that, I fear, was not intended. Which means, by (nongrammatical) implication, that the discrepancy between the obviously intended meaning of "un equivocably" and its structurally supported significance was the cause of the un pleasant jolt experienced by the spotting reader. PS.--It is of course possible, and even likely, that "unequivocably" was just a typo for "equivocally." Alexander Code; PhD :v '. ' f i ! ;; > ; I . > , r }- ' 110 JAMA. April 8.1968 Vol 204. No 2 r ,, I sasaass ASARCO ALV 0002154