Presented at the Annual Meeting of The Cancer Control Council Los Angeles, California, July 2, 1977
An immense number of carcinogens are produced and spread throughout our modern technological society. They permeate our air, our food, and our drinking water. Our main source of knowledge about carcinogens still comes from cancer epidemics among industrial workers. Cancer of airway passages, urinary systems, digestive systems, skin, and various organs have been definitely related to such widespread pollutants as the volatile by-products of combustion, asbestos, arsenic, vinyl chloride, nitrosamines, nephtalamines, benzidines and many other substances. Many of these substances find their way into almost daily contact with the population of North America. Heavy handed attempts have been made to link industrial diseases to smoking. However, abundant evidence now exists that when it comes to cancer, WORKING KILLS SMOKERS RATHER THAN SMOKING KILLING WORKERS.
Cancer is a statistician’s disease. This does not mean that statisticians suffer more from the disease than do other mortals. It is a statistician’s disease because the complex causes that are cancer’s antecedents, making their effects felt over prolonged time periods, can be ferreted out best through statistical studies. At least I flatter myself that as a statistician I am a necessary cog in the machinery.
In the broadest sense, a carcinogen is a condition, an effective contact with some substance, a set of circumstances, that in due course increase the probability of developing cancer. Such conditions abound and so do carcinogens then. Most of them appear to be created by man for his own benefit or, better, lack of benefit.
That is not to say that many carcinogens do not occur freely. The ultraviolet rays of the sun are a major cause of skin cancer. Ionizing radiation occurs naturally in many locations and we all are exposed to cosmic radiation. Improper nutrition plays a role and so do many mechanical and chemical stimulations. But the number of all naturally occurring opportunities pales in comparison with the number of carcinogens which are produced by modern industrial processes.
A proper assessment of the extent of the man made disaster has only been made lately, perhaps as recent as the last decade. That carcinogens are produced indeed has been long suspected. But the history of modern health research has been one of failures of failures to test the many byproducts of technology for their carcinogenic properties, failures to test them properly, and of failures to acknowledge many results of such tests when they clearly indicated that a health hazard was created. Only when conscientious citizens brought pressure to bear on the health establishment, were responsible investigations undertaken. Publicly supported studies have now accumulated much of the evidence of what is or what is not carcinogenic. But by far our best source of knowledge are studies of cancer epidemics among industrial workers. Man, for the most part, has been his own best guinea pig and workers in mills, factories, and fields are most exposed and most vulnerable to the carcinogenic effect of technology. Independent of the moral question raised by this inhuman approach to health studies, industrial workers are the best test subjects. They constitute a large number of exposed subjects, they are exposed often and to high doses, exposure usually are at high temperatures where contact is much more volatile, and they are exposed over prolonged periods.
It would be an illusion, however, to assume that only industrial workers are exposed to industry produced hazards. Many of these hazards are spread throughout the community, often with undiminished force. The effluences of smoke stacks and the discharges of industrial sewers into the air and water are subject to ecological forces and become the increasingly concentrated companions of human existence. The industrial worker may be at the point, but the final target is all of us.
THE MANY SOURCES OF INDUSTRIAL POLLUTION
The recognition of industrially caused cancers leads back to the observation by Percival Pott in 1775 of the high frequency with which cancer of the scrotum occurred among London chimney sweeps. This observation lead in time to the recognition that perhaps the greatest number of carcinogens come from the volatile by-products of combustion of organic fuels such as coal and petroleum and from substances eventually recovered from these by-products, especially tars. Most exposed are workers in and around coke ovens. According to the U.S. Bureau of Mines, there were 13,218 coke ovens in operation in the U.S. in 1970. Workers in and around foundries or steel making operations or any intensely burning organic fuel are similarly exposed. But exposure to these volatile chemicals is not limited to workers. Very much the same materials are released into the atmosphere from home heating devices and automobile exhausts.
About a million tons of asbestos are used in the United States, each year. It has been estimated that 40,000 insulation workers are directly exposed to asbestos dust. Much of the asbestos used in construction now is sprayed on.
Fibres working loose from coatings are slowly circulated into the air through heating and ventilation ducts. Another estimated 50,000 workers are involved in the manufacture of asbestos containing products. Because of the countless uses of asbestos, fibres are now found in textiles, in food, in drink, in practically every other place including baby powder. One study in New York found that over 47% of autopsied lungs contains asbestos bodies. Another study found chrysotile asbestos in lungs of 104 out of 123 people coming to autopsy at random.
Arsenic is found in larger amounts in the general environment. To this naturally occurring amounts are added 35,000 tons of arsenic trioxide in the United States each year. Arsenic is used in pesticides, in pigments, in the manufacture of glass, in textile printings, in tanning, in taxidermy, in antifouling paints to control sludge formation, in cutting oils. Arsens are often used in alloys. NIOSH estimates that approximately 1,500,000 workers are exposed to inorganic arsenic.
Here we have then three sources of pollutants with which most individuals in the modern world have daily contact. All of them produce cancer in the work place.
The first report of unusual lung cancer experience in men engaged in coal carbonization came from Japan where gas producers showed lung cancer mortality many times that obeserved from other japanese steel workers. The excess lung cancer risk was confirmed about the same time by British studies of death certificates. In 1952, Richard Doll observed in the study of gas works pensioners an 81% excess of lung cancer death in comparison with the general population. In the United States, Lloyd reported recently that many coke oven workers had lung cancer mortality rate 21/2 times that predicted by the experience of all steel workers. These figures have been confirmed again by recent studies of U.S. and Canadian workers.
However, cancer of the lung is not the only cancer found. An excess risk of bladder cancer has now been confirmed for workers exposed to coal carbonization. Bladder cancer is a rare form of cancer and the very fact it was observed indicates that it’s rate among coke oven workers is very high. Coke oven workers experience about three times the expected rate of kidney cancer. Other cancers that have been reported are of the larynx, nasal sinuses, pancreas, blood forming organs and stomach. However, the major site of attack for workers exposed to carbonized byproducts have been skin, lung, and urinary organs.
The report of bronchogenic carcinomas among asbestos workers are so many as to establish asbestos as a leading cause of lung cancer among them. In fact, one recent study found that 80% of lung cancer patients and another that 30% of patients with squamous cell carcinoma of the larynx report occupational or other exposures to asbestos.
Another frequent type of cancer among asbestos workers are mesotheliomas. Ten to 15% of cancer deaths among asbestos workers are due to that disease. Other epidemiological studies have consistently shown an excess risk of a number of other cancers among asbestos workers, especially of the gastric and intestinal tracts following exposure to mixed fibres. Dr. Muriel Newhouse reported that of 76 mesothelioma patients, 31 worked with asbestos, 9 were relatives of asbestos workers (pointing to the direct danger to wives and children when the breadwinner brings home toxic substances on his hair, skin, and clothing) and 11 lived near asbestos using factories.
Lung cancer has been attributed to arsenic exposures since 1924 when a high lung cancer rate was observed among nickel refining workers in South Wales. Since then nickel itself was found to be a carcinogen. However a number of factory studies established between 1936 to 1948 that workers exposed to arsenic had twice the incidence of respiratory cancer and ten times the incidence of cancer of the skin than did the general population. The incidence of lung cancer appears to be directly related to the amount of exposure to arsenic. Lee and Fraumeni of the U.S. National Cancer Institute found the lung cancer prevalence for groups that differed in exposure to arsenic from lights to medium to heavy were respectively 2.4, 4.8 and 6.7 times the expected rates.
Here are some other substances definitely proven to be carcinogens.
Besides many serious harmful effects which has been reported among workers exposed to chromium dusts are lung cancer. An increasing number of workers are exposed to benzenes, and alpha and beta nephtalamines. These chemicals are known to cause cancer of the bladder, pancreas, and various other organs. Vinyl chloride and polyvinyl chloride are known to cause gall bladder cancer, cancer of the nervous system, liver, kidney and lung. There is an increasing incidence of bone marrow cancer and multiple melonomas and myloid leukemia among radiation exposed workers. The cancer producing properties of nitrosamines were first found in workers using cutting oil and hydraulic fluid. Workers in the rubber industry have a high incidence of tumors of the nervous system, cancer of the pancreas, cancer of the lymphatic/ homopoetic systems, cancer of the kidney, and cancer of the stomach.
I have carefully limited myself to those sources of cancer producing agents for which definite evidence has been accumulated. But what of substances for which no such observations exists? What of the many products based on chlorinated hydrocarbons or on arsenic compounds that have flooded the environment through heavy use as pesticides and herbicides? How many food preservatives are based on nitrosamines? What about food coloring chemicals? What about plastic food packaging materials that leach out various highly toxic chemicals? What about aerosol propellants of cosmetic sprays that contain vinyl chloride? (300,000,000 lb. of vinyl chloride escape each year in the air from aerosol use.) No answers to most such questions exist because no answers to most such questions are seriously sought. But when tests are made of the carcinogenic properties of many common chemicals, the results often are surprising. In the late 1960s, the National Cancer Institute tested 120 commonly used household chemicals for carcinogenic properties. Eleven of them were found to be carcinogens and one, a teratogen. As we examine our environment more and more closely, the number of hitherto unsuspected carcinogens increases. For instance sulphur dioxide, which has been associated mostly with malodorous irritation, is now thought to increase the prevalence of lung cancer among smelter workers.
WHAT ABOUT SMOKING
No discussion of cancer is complete without turning to the role of tobacco in causing cancer,especially of the lung.
The findings from occupational health studies are in direct conflict with the popular opinion that lung cancer is primarily a disease of smokers. And indeed, ever since the Advisory Conunittee to the Surgeon General had concluded in their report Smoking and Health that it was smoking and not occupational exposures that caused lung cancer, the popular opinion has remained that smoking is primarily to blame for cancer of airway passages. That conclusion was based on very few occupational health studies that examined both the occupational exposures and the smoking habits of workers. But a mass of new evidence gathered since 1964 now compels us to reexamine that conclusion. Unfortunately there are also many vested interests that seek to keep attention focused on smoking and to divert as much attention as possible away from industrial sources of cancer. Our discussion would be incomplete if we were not to point to some of these “interests” as well.
NEW EVIDENCE ABOUT THE EFFECT OF SMOKING VERSUS THE EFFECT OF INDUSTRIAL EXPOSURE AS A CAUSE OF LUNG CANCER
A number of investigations of lung cancer epidemics among industrial workers conducted during the last decade have compared the prevalence of lung cancer among smoking and non-smoking workers. With two notable exceptions, all studies agree that the prevalence of lung cancer is practically the same among smoking and non-smoking industrial workers. In fact, in some studies the prevalence of lung cancer was higher among industrial workers who did not smoke than among industrial workers who did smoke. The studies were of workers exposed to coke oven emissions, to asbestos, to uranium mining, to bimethyl methyl ether, to vinyl chloride, and others.
One of the two exceptions, Doll’s study of physicians in England, does not disagree so much with the findings of occupational effects but, at the best, would point to cigarette smoking as one cause of lung cancer but not necessarily its exclusive antecedent. In addition Doll has failed to look into other carcinogenic exposure among physicians such as to anesthetics or radiation. The other study by the American Cancer Society, finds a much higher incidence of lung cancer among smoking than non-smoking asbestos workers. But, there appeared to be a number of curious difficulties with that study. The Criterion Document on Asbestos Exposure, published by NIOSH, has challenged the interpretation given to that study in light of other evidence.
Finally, a series of studies by my ‘associates, Dr. Weinkam and myself have now established that the comparison of smokers and nonsmokers in a number of studies has really hidden a comparison between occupations. In our recent article in the Journal of Occupational Medicine we find that when the smoking prevalence is compared among different occupations, occupations in which smoking is heaviest turn out to be those which expose workers with a high probability to irritating toxic dusts and fumes while occupations in which smoking is infrequent are primarily of teaching or professional workers. Thus a comparison between smokers and nonsmokers primarily is a comparison between two groups of which one, the smokers, consists of a large proportion of blue collar and a small proportion of occupational workers and managers and of which the other, the non-smokers, consist of a small proportion of blue collar and a larger proportion of professi6nals and managers.
In summary, new evidence uncovered in the last decade has pointed toward industry as a major source of carcinogens that cause cancer of the lung. The extent to which tobacco also causes that disease needs yet to be established by properly conducted studies that control for occupational exposure of smokers and nonsmokers.
AND THEN THERE ARE VESTED INTERESTS
On May 12, 1977 Dr. Kotin, senior VicePresident for Health, Safety and Environmental of Johns-Manville addressed the National Commission of Smoking and Public Policy and among others said: “In the practical sense, were it not for the associating of cigarette smoking with occupational exposure and chemical or physical carcinogens (e.g. uranium mining, asbestos, coke oven exposure, chromates and nickle, lung cancer in these occupational groups would virtually disappear as a hazard of the work place).”
Dr. Bundy, of the United States Steel Corporation allowed that: “I could not say flatly whether Dr. Kotin is right or wrong, but the evidence at least in so far as the asbestos and uranium mining fields and possibly the coke oven industry would seem to point in the direction he indicates.”
The Occupational Health and Safety Letter that carried these comments also included answers by Dr. Wagoner of NIOSH that “Dr. Kotin’s opinion is not,in accord with the facts as derived from NIOSH studies and data from the International Cancer Research Group in Lyons.” And by myself that “whenever an excessive industrial incidence of lung cancer has been investigated, there either was very little or no difference between smokers and non-smokers in that industry”.
This exchange clearly marks the lines of battle between the industry and environmentalists and occupational health workers. Ever since it has been discovered that workers in some industries suffer with high frequency from cancers and from chronic obstructive pulmonary diseases, industry spokesmen have blamed these diseases on smoking. Paul Brodeur in his The Expendable American relates how Dr. Grant, medical consultant for the Pittsburgh Corning Corporation which managed the now defunct asbestos plant in Tyler, Texas, blamed the excessive cancer rate among the workers on smoking. Only a few days ago (June 21, 1977) the Vancouver Sun reported that during the last twenty years, 132 workers at an Italian dye plant have died from confirmed and suspected cancer of the bladder due to exposure to betanaftalamine and benzidine. The article also quoted the factory doctor as saying that workers should just “drink less and smoke less”. (The article reports that the managers of the plant received jail sentences. It says nothing about punishment meted out to the doctor.)
There are substantial economic factors at work. To meet acceptable standards of exposure to both workers and the community at large would require industry to make heavy investments in air cleaning devices. Industry has a long record of fighting setting and enforcement of any standards and, to their shame, regulatory agencies have just as long a record of caving in to industry pressure. In addition, compensation claims are expensive as well to both industry and government. Smoking has been a Godsend in dealing with occupational injuries. In a recent Institute on Occupational Disease Claims, sponsored by the School for Workers at the University of Wisconsin, it became clear that occupational claims for a variety of lung diseases were denied altogether or seriously cut when workers had a history of smoking. While the occupational health problems produced by industry cannot be swept under the rug, they can at least be held temporarily at bay by NO SMOKING signs. Perhaps President Nixon, in his 1972 report to Congress on “Environmental Pollution Effects” expressed most crudely this convenient interest shared by government and industry. He charged that for lung cancer “95% of the disease is attributable to cigarette smoking” as a prelude to diverting much needed funds from environmental and occupational health research.
Finally it is unfortunate that vested interests are not only found in industry and government and not only controlled by ‘economic and financial considerations. A distinguished committee of Scientists, carried away by commendable zeal, pronounced in 1964 on the basis of rather questionable evidence that it was smoking and not occupation or air pollution exposures that caused lung cancer and chronic obstructive lung disease. Now it finds itself unable to retract on the basis of new evidence. Nor does the U.S. Public Health Service and the National Institute of Health help matters because having sold themselves on cigarette smoking as the major cause of cancer in the past, the bureaucratic mind does not follow easily changes in scientific understanding. But because smoking is used so often to divert attention from environmental and occupational health problems, it is high time that the effect of tobacco is reassessed as opposed to and relation to other antecedents of cancer.
An immense number of carcinogens are produced and spread throughout our modern technological society. They permeate our air, our food, and our drinking water. Our main source of knowledge about carcinogens still comes from cancer epidemics among industrial workers. Cancer of airway passages, urinary systems, digestive systems, skin, and various organs have been definitely related to such widespread pollutants as the volatile by-products of combustion, asbestos, arsenic, vinyl chloride, nitrosamines, nephtalamines, benzidines and many other substances. Many of these substances find their way into almost daily contact with the population of North America.
Heavy handed attempts have been made to link industrial diseases to smoking. However, abundant evidence now exists that when it comes to cancer, WORKING KILLS SMOKERS RATHER THAN SMOKING KILLING WORKERS.
“The greatest dangers of liberty lurk in the insidious encroachment by men of zeal, well meaning but without understanding.”
– U.S. Supreme Court Justice Louis Brandeis.