It’s the Real Thing: Coke Oven Cancer

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It’s the Real Thing: Coke Oven Cancer

by Joel Schwartz

‘Science for the People’ Vol. 12, No. 3, May-June 1980, p. #11-16

Joel Schwartz teaches Environmental and Occupational Health Sciences at the University of Illinois School of Public Health. He works in the area of environmentally caused cancer, and is an active member of the Chicago Area Committee on Occupational Safety and Health (CACOSH). 

Coke batteries are like a classical conception of hell, with workers doing their jobs amid fire and brimstone. Besides being extremely dirty and unpleasant, work in coke ovens exposes workers to high levels of carcinogens. As a result, coke oven workers have high rates of cancer. Coke plants contribute significantly to air pollution in residential areas near mills, increasing the lung cancer rates among residents. 

For nearly a decade a major battle has been waged over conditions in coke plants. While the steel industry has resisted clean-up efforts tooth and nail, the United Steel Workers of America (USWA), prodded by rank-and-file coke oven workers, has won definite improvements in conditions in coke plants. Still, most plants did not comply with the Occupational Safety and Health Administration’s (OSHA) new standard for coke ovens by the January 1980 deadline, despite the standard’s technological feasibility1. (The standard is far less strict than needed to protect workers’ health anyway.) The American steel industry has seen repeated plant closings and layoffs, and the threat of further, more massive layoffs hangs over the workers. Although steel companies claim that a clean-up is too costly and would further damage their ailing industry, inexpensive methods are available to reduce pollution levels. The scientific community has played its part in the drama, with many scientists involved in covering up the possible health hazard, and a few playing an important role in documenting the hazard. 

Racism is also involved. The steel industry has a long history of keeping workers divided by assigning jobs according to race. Coke plant jobs, among the dirtiest and most grueling, have traditionally gone to black and other minority workers. Additionally, the communities surrounding many mills tend to be disproportionately black and minority. 

Coke ovens (arranged in batteries) are an essential part of the steel-making process. Coal is heated in the ovens to very high temperatures, giving off impurities, and leaving coke which is essentially pure carbon. The coke is used as a reducing agent and fuel in the blast furnace. In the process of coke production a number of carcinogenic substances are produced in large quantities, including benzpyrene (BP), benzine, phenols, anilines, and sulfur dioxide (which has been shown to increase the potency of carcinogens). A study by Dr. J.W. Lloyd, published in the early 1970s, showed that topside workers (who work on top of the coke ovens) with five or more years experience had a lung cancer rate ten times that of the general steelworker population, and coke oven workers overall had a lung cancer rate 2½ times that of the general steelworker population 2. Subsequent studies confirmed these results, and all showed that coke plant workers suffered from excessive rates of kidney and prostate cancer, as well as of chronic lung disease and heart attacks. To get an idea of what a ten-fold excess lung cancer rate means, it should be noted that normally lung cancer accounts for about 5 percent of all deaths among men in the U.S. 

There are some 22,000 coke oven workers in the U.S., with a disproportionately high number being black and other minorities 3. When Lloyd first analyzed his data, it appeared that the excessive cancer rates appeared only among blacks. Further checking revealed that when proper controls were made for place of work, the cancer rates depended only on place of work and had nothing to do with race. However blacks tended to have the dirtiest jobs. 

The Fight Back 

The first activity by steel workers in recent years to improve conditions was initiated by Dan Hannon, president of the USWA local at U.S. Steel’s Clairton works near Pittsburgh. Hannon noticed that death and disease rates among workers in the coke plant seemed to be very high. He took his case to Washington, testifying before House and Senate Committees about conditions in the coke plants. Back in Pittsburgh he spoke at several local unions and was instrumental in educating workers and organizing them to demand improved conditions. U.S. Steel attempted to harass and intimidate Hannon for his efforts, for example by shifting him to a work area where no phone was available, which made it very difficult to be a local president. The intimidation tactics did not work, and Hannon continued his efforts.

Soon after activities began in Clairton, Lloyd’s study was published and received widespread publicity. The newly formed OSHA, fresh from winning stricter standards for asbestos and vinyl chloride, moved to adopt a new coke oven standard. The steel industry had already been trying to get the old standard tossed out, and geared up for a massive battle to avoid a major change. The USWA mobilized its forces to fight for an improved standard, but its ability to fight was limited by the non-struggle position of leaders who had negotiated a no-strike agreement, and whose racism made them unwilling to go all out for the sake of mostly black and minority workers. 

Both the old and new standards deserve comment. The old standard for coke oven emissions was 0.20 milligrams of particulate matter (called the benzene soluble fraction) per cubic meter of air (mg/m3). It was apparently arbitrarily set, as the standards committee gave no scientific reason for selecting that figure 4. Although the hydrocarbons in coke plant emissions have since the 18th century been known to cause cancer, and several studies 5 from the U.S., Great Britain, and Japan document very high cancer rates among workers, several important articles in the U.S. literature state that the cancer threat from coke ovens is either slight or nonexistent 6. These articles played an important role in supporting the previous standard. 

The new coke oven emissions standard, set by OSHA and backed by USWA, is 0.15 mg/m3 of benzene soluble fraction, or 75 per cent of the old standard. If enforced, this standard would be a big improvement, because actual exposure levels in coke ovens generally exceed the exposure limit by a factor of 10 to 100. The new standard also carries a provision requiring yearly medical exams for coke plant workers, which is an important benefit. Still, this standard will not eliminate lung cancer from coke oven emissions. It was revealed that the standard was set by determining the lowest level of emissions that OSHA considered economically feasible for the steel industry to achieve7. The exposure level in the standard was set to equal the levels at the Fairfield, Alabama plant of U.S. Steel, deemed the best in the nation for controlling emissions. It was in no way based on an attempt to meet a certain level of health protection. 

While the USWA committed itself to having the standard implemented, rank and file coke plant workers in several areas took action to pressure the union to take a stronger stance and obtain improvements in local conditions. One local in Canada won for coke plant workers four hours relief time for every four hours worked. In Sparrows Point, Maryland, a work stoppage by coke plant workers resulted in guarantees by the company to make major improvements in coke oven conditions. In Fontana, California, coke plant workers from Kaiser Steel jammed a meeting of the State Air Resources Board demanding a cleanup. A few years later the Board forced Kaiser to sign a consent order which committed it to make major improvements. Workers at the Inland Steel plant in Indiana came close to striking over the coke plant workers’ demands. These included four hours relief time for every four hours worked and greatly increased oven maintenance. Neither was granted. The latter demand would have increased jobs, and lowered pollution levels, as much of the exposure results from leaks and poorly fitting doors on the ovens, problems which could be resolved by proper maintenance. 

The steel monopolies did everything they could to block implementation of the new standard. One channel they used was the courts. The USWA spent $1 million and a large amount of time and effort in a successful defense of the standard which wound up being decided by the Supreme Court. The steel companies’ main arguments were that the steel industry was in a crisis, and that the new regulations were so costly they would result in massive layoffs and general devastation of an already suffering industry. The truth is that meeting the regulations would eat into the industry’s high profits slightly, but overall the cost would be small compared to their profits 8. In fact, exposure could be reduced to far lower levels than required by the OSHA standard — at relatively little cost 9. Furthermore, although there is a crisis in the U.S. steel industry, the blame falls on the excessive profits of the industry, and it will not be solved by attacking working conditions and living standards of steel workers. In spite of the crisis, profits in the industry are high, about 50 percent higher in 1979 than in 1978.

Emissions Control 

Technology is available to reduce greatly the exposure levels, and at reasonable cost. For example, a half dozen methods are available for reducing emissions during the loading of coke into the ovens — called charging, a major emissions source. An enclosed pipe system for loading coal into the ovens could be built into new coke ovens for less than the cost of traditional systems 10. Unlike the old system of loading the coal from a rail car on top of the oven through an open door, little gas escapes into the air from a pipeline. 

For older ovens a jumper system could be installed cheaply. In this system, gases from the oven being charged are moved by suction through a jumper pipe to another oven, rather than escaping into the atmosphere. Another system, now in use at the Jones and Laughlin steel mill in Pittsburgh, uses greater steam pressure to suck up coke oven gases, blocks gas escape routes, and uses special doors to seal hoppers on the loading cars. These systems cut emissions from the charging process by about 85 percent. The cost of installation and operation of either system has been calculated at less than 1 percent of the cost of coke 11

The quenching operation, the cooling of the hot coke, is another major source of pollution in which emissions can be readily reduced. Coke is usually quenched in the U.S. with waste water, causing a subsequent release of high levels of pollutants with the steam into the air. The dry quenching process uses inert gases (nitrogen and carbon dioxide) to absorb heat from the coke. The gas then transfers the heat to a waste heat boiler to make steam which can be used to make electricity or preheat coal. Emissions from quenching are reduced by over 90 percent by this process 12. Dry quenching systems are used in steel mills throughout the world, including mills in France, Germany, Czechoslovakia, the Soviet Union, and Japan. Although conversion from wet quenching to dry quenching requires significant capital investment, the savings from capturing the waste heat and producing superior coke make these investments pay for themselves in four years. One dry quenching operation is being planned for a steel mill in Weirton, West Virginia, but this only with financing by the Environmental Protection Agency (EPA). Apparently U.S. steel companies are avoiding the method because they prefer to put capital into more profitable investments outside the steel industry. Much of the record profit now being made by U.S. steel monopolies is being sunk into the mining industry in such countries as South Africa and Brazil. 

In general, the steel industry has attempted to blame recent plant closings in large part on environmental as well as health and safety regulations, but these accusations are false. First, with expenditures of about 1 percent of steel production costs, emissions levels for coke ovens could be reduced to far below that required by the OSHA standard, and in the long run some pollution control techniques would save money 13. In other countries steel producers have installed more pollution control devices, met stricter standards, yet still produced steel more cheaply than their U.S. counterparts. Bernie Bloom, Director of the EPA Enforcement Division, studied pollution control technology in Japan, a nation which produces many types of steel at 80 percent of the cost in the U.S. He concluded that the Japanese steel industry had installed technology in all its new plants which far surpassed technology in place in the U.S. Every coke oven in Japan had hardware for capturing pushing emissions and desulfuring coke oven gas 14. In another country, the Soviet Union, the use of the dry quenching method is mandatory. 

The main reasons for the steel crisis and the closing of steel plants are that demand for steel in the U.S. is low 15 and that the U.S. steel industry has let plants run down by refusing to install new equipment or properly maintain old equipment. Two plants that were closed recently, the Youngstown Sheet and Tube and the Lackawana works of Bethlehem Steel, were closed because they were in bad repair and saddled with obsolete technology. A recent Journal of Commerce article noted, “Steel companies are closing older plants and laying off thousands of workers in an effort to reduce costs and improve profit margins.” 16 

Cancer and the Workplace 

As the problem of cancer resulting from exposure to industrially generated chemicals has come to light, a controversy has arisen as to its importance. Some epidemiologists and members of the American Industrial Health Council (AIHC), a coalition of various industrial concerns, estimate that at most 5 percent of all cancers result from exposure to industrial chemicals (1). Unfortunately, the numbers from which these estimates were derived cannot be found in their respective publications. 

Recently, a rather large group of epidemiologists at the National Cancer Institute (NCI), the National Institute of Occupational Safety and Health (NIOSH), and the National Institute of Environmental Health Sciences (NIEHS) have estimated that 20-38 percent of all cancers might be due, at least in part, to occupational exposure (2). Their evaluation is based on a simple calculation involving estimates of the increased risk of cancer from exposure to a specific substance, and estimates of the number of workers exposed to that substance. There is sufficient data to make this type of calculation on only a limited number of recognized human carcinogens, including arsenic, asbestos, benzene, nickel, chromium, coal tar pitch, coke oven emissions, iron oxide, and vinyl chloride. 

The following are examples of the findings: Of four million workers who have had heavy exposure to asbestos, 20-25 percent can be expected to die of lung cancer, 7-10 percent of mesothelioma (cancer of the lining of the lung), and 8-9 percent of gastro-intestinal cancer. Coke oven workers face two-and-a-half times as great a chance of dying from lung cancer and are seven times as likely to die from kidney cancer as the general population. Smelter workers heavily exposed to arsenic trioxide for more than 15 years had an eight-fold excess of respiratory cancer. Other well-known occupational carcinogens include vinyl chloride, bis-chloromethylether, benzene, and benzopyrene. In a retrospective study of a coal tar dye plant where benzidine was used, 44 percent of the workers exposed to benzidine developed bladder tumors. Another study showed that 94 percent of workers exposed to benzidine and beta-napthalene for over five years developed bladder tumors. 

Certain groups of workers are known to have higher incidences of cancer, although the exact agent responsible is unknown. For example, barbers are known to get more larynx cancer, painters more leukemia and stomach cancer, leather and shoe workers more nasal cavity and sinus cancers, and chemists more lymphomas, leukemias, Hodgkin’s disease, and pancreatic cancer. 

U.S. counties in which certain types of industries are located are known to have higher rates of certain types of cancer; for instance, counties with rubber industries have more leukemia and prostate cancer, chemical industries more stomach and bladder cancer, paper industries more lung cancer, and petrochemical industries more cancers of the lung, skin, nasal cavity and sinuses. 

It should be made clear, however, that all the studies of cancers resulting from industrial chemicals have been made on chemicals used for many years. No one can predict the effects that the great boom in organic chemical production, which began around 1945, and continued to grow rapidly into the 1970s (3) will have on cancer incidence in the future. The reason for this is that there often is a 20-40 year lag period between first exposure to a substance and the first appearance of cancer symptoms. Thus the cancer incidence resulting from the boom in chemical production may only be beginning.

Do we have reason to expect an increase in cancer incidence from this boom? Unfortunately, yes. While the Occupational Safety and Health Administration (OSHA) currently recognizes and regulates only 20 chemicals as human carcinogens, the International Agency for Research of Cancer (IARC) lists 221 chemicals for which there are good data indicating animal carcinogenicity, and NIOSH lists over 2000 chemicals as suspected carcinogens. There are currently 60-70,000 chemicals in production, and the list is expanding at a rate of about 700 per year. Unfortunately, many have not been tested for carcinogenicity. In addition the current Threshold Limiting Value (TLV) for a number of chemicals allows workers to be exposed to a daily dose very close to the dose known to give cancer to 50 percent of exposed experimental animals (after correction for body weight differences). Although these facts cannot be used to reliably predict the future, they suggest an alarming potential problem.

To deal with this problem, OSHA, under its current progressive leadership, has recently released its so-called “Generic Carcinogen Standards.”(4) OSHA estimates this new procedure will allow 10 new substances per year to be regulated as carcinogens, an improvement from the previous rate of about two per year. Labor finds this improvement a step in the right direction, but insufficient given the magnitude of the problem. In spite of the concessions made by OSHA to industry regarding the standards, the AIHC and others have filed for federal appeals court review of the policy, which will undoubtedly delay its implementation for years. 

While the courts decide on the appropriateness of the OSHA standards, and scientists debate just how many workers are victims of occupational cancer, the incontrovertible point is — an improved policy is needed because too many workers are dying. Even if we accepted the conservative figure of 5 percent of all U.S. cancer deaths being due to occupational exposures, that amounts to 20,000 deaths per year. And unlike cancers due to so-called “lifestyle” factors (e.g., cigarettes and alcohol), these cancers are totally imposed on people. — workers have no choice over production priorities or production methods. Occupational cancers are a problem we can prevent now.

Ed Loechler 


1. J. Higgenson, “A hazardous society? Individual versus community responsibility in cancer prevention,” American Journal of Public Health 66, 1976, pp. 359-366. E.L. Wynder and G.B. Gori, “Guest Editorial: Contribution of the environment to cancer incidence: an epidemiological exercise.” Journal of the National Cancer Institute 58, 1977, pp.825-832.

2. K. Bridbord et al., “Estimates of the fraction of cancer in the United States related to occupational factors.” A draft evaluation of this problem by the NCI. NIEHS, and NIOSH dated Sept. 15, 1978. 

3. From 1950 to 1974, production of synthetic rubber, pesticides, and plastics increased from (all in billions of pounds per year) 0.8 to 6, 2.5 to 12.5, and 1.3 and 32, respectively. For a detailed breakdown see: Science 204, 1979, p. 587. 

4. Generic Carcinogen Standards: OSHA Federal Regulations 45, Jan. 22, 1980. For reviews, see: Nature 283, 1980, p.320 and Business Week. Feb. 4, 1980, p.76. 


Moreover, lowering emissions at existing plants creates, rather than eliminates, jobs. Strict maintenance, repairing doors, plugging leaks requires more workers but slows down production. At the U.S. Steel plant at Fairfield, 16 to 22 workers per unit shift were added to enforce the new coke oven standard. Similar changes took place at the Clairton plant. 

The Environmental Hazards 

Coke oven emissions constitute a serious health hazard to the surrounding community as well as to coke oven workers. The EPA estimates that coke oven operations contribute about 19 percent of the nation’s air pollution burden of BP, and about 15 percent of polycyclic and aromatic hydrocarbons 17. They are also major sources of gaseous hydrocarbons, sulfur oxides, and nitrogen oxides, many of which cause cancer.

Since most of these emissions are concentrated in the vicinity of coke ovens, the health effects on people living near plants are much more pronounced than the 15- or 19-percent figure would indicate. The most recent EPA figures state that the average ambient air concentration of BP for cities with coke ovens is 1.21 nanograms per cubic meter (ng/m3), compared to 0.78 for 13 cities surveyed without coke ovens, and less than 0.1 for rural areas 18. For the benzene soluble fraction of particulate air pollution, the figures are 4.21 micrograms per cubic meter for coke oven cities, 3.75 for cities without coke ovens, and 0.95 for rural areas 19

Even more pronounced differences can be seen when air concentrations of BP at different areas within cities are considered. For example, in Alleghany County, Pennsylvania, the average air concentration of BP varies from 51.95 ng/m3 at a site 2 kilometers from the U.S. Steel plant, to 1.64 at another site. Four of the eleven sampling stations had average readings in excess of 10 ng/m3 20

The EPA estimates that over 200,000 people in the U.S. live in areas where the ambient air concentration of BP from coke oven emissions alone exceeds 10 ng/m3, and almost one million people in regions where the contribution from coke ovens exceeds 5 ng/m3 (compared to a 0.38 ng/m3 average for cities without coke ovens). More than 8 million people live in cities where coke ovens contribute 1 ng/m3 of BP or more to the air. Thus coke oven emissions make a substantial contribution to urban air pollution. 

Numerous studies have linked high lung cancer mortality rates to living in more polluted areas. Similarly, chronic respiratory disease has been attributed to exposure to both particulate air pollutants and sulfur oxides. While no studies have been performed that directly link coke oven emissions to either of these diseases, there is ample evidence indicating that pollution from coke ovens makes a serious contribution to cancer among people residing near plants. 

An analysis of lung cancer mortality rates of counties with coke ovens reveals higher rates in these counties than in the state as a whole and in neighboring counties. The rates are, in general, higher for both men and women. These differences in mortality are in some instances very high, up to 40 percent. The rates for women generally show the same pattern as for men, which tends to indicate that the differences are due, in part to ambient exposures, not simply to workplace exposures. Women were not employed in steel mills in significant numbers during the period of the study. 

The Situation Today 

The January 1980 deadline for compliance with the new coke oven standard has passed, but the battle to end the carnage continues with greater interest and participation by coke oven workers. There have been some major improvements to date, but the powerful steel industry, aided by the deepening steel crisis and a media blitz about how regulation is ruining our economy and causing inflation, has successfully dragged its feet in many instances. Two years ago, an OSHA inspection at the Indiana plant of Inland Steel indicated that exposure levels for many workers were still ten to 100 times those permitted by the standard. Only one plant had met the OSHA standard by the required date, and most are far from compliance. OSHA has not announced how it will deal with plants not meeting the standard. 

The actual situations vary from plant to plant. In most coke batteries workers report some changes — new ventilating systems have been brought in, spare doors have been purchased, more time is allowed for maintenance, and some mills have even installed pipeline changing. Most of these changes have come as a response to OSHA inspection (OSHA has a special team of experts whose only function is to inspect coke plants), but many workers fear backsliding after the inspectors leave. 

Several steel locals are also fighting to reduce pollutant levels in the community. There is a close connection between the workplace and community pollutant levels as the same process changes and maintenance improvements that would reduce workplace pollution would also reduce ambient pollution. Three USWA locals have asked to participate in EPA suits to make the plants comply with environmental regulations. The workers argue that the EPA cannot by itself properly monitor emissions, but that they, because of their position in the plant, can determine when doors are not cleaned or replaced, when pipelines are leaking, when coke is incompletely charged, and, in general, when proper procedures to control emissions are not followed. 

The USWA has been sponsoring conferences for coke oven workers throughout the country, which have had broad rank and file participation. At a recent conference in the Illinois-Indiana district, coke workers formulated demands for the coming contract including 4 hours relief time for every 4 hours worked, full disclosure of medical test results, full compliance with the OSHA standard, and adequate maintenance crews with sufficient time to clean doors and plug leaks. The mood of workers at the conference was militant and optimistic. Despite the economic hardships in the industry the workers fully intended to “get the coke plants off Death Row,” as the buttons they sold declared.

>> Back to Vol. 12, No. 3 <<


  1. Frank Goldsmith, “Coke Ovens, Steel’s Big Demon Wins Again,” New Engineer, Jan. 1977, p. 26.
  2.  J.W. Lloyd, “Long Term Mortality Study of Steelworkers,” Journal of Occupational Medicine, vol. 13, 1971, p. 53.
  3. T. Mancuso and T. Sterling, “Lung Cancer Among Black and White Migrants in the U.S.,” Journal of the National Medical Association, vol. 67, 1975, p. 106.
  4. American Congress of Government Industrial Hygienicists, Documentation for Threshold Limit Values, Cincinnati, Ohio, 45202.
  5. W.C. Hueper, Occupational and Environmental Cancers of the Respiratory System, Springer-Verlag, 1966, chapters 9, 10.
  6. Falk, Kotin, and Mehler, “The Carcinogenicity of Certain Polyaromatic Hydrocarbons for Man,” Archives of Environmental Health, vol. 8, 1964, p. 721.
  7. Standard on coke oven emissions, U.S. Federal Register, vol. 41 no. 206, Oct. 22, 1976, p. 46742.
  8.  Frank Goldsmith, “Coke Ovens, Steel’s Big Demon Wins Again,” New Engineer, Jan. 1977, p. 26.
  9.  Frank Goldsmith, “Coke Ovens, Steel’s Big Demon Wins Again,” New Engineer, Jan. 1977, p. 26.
  10.  Frank Goldsmith, “Coke Ovens, Steel’s Big Demon Wins Again,” New Engineer, Jan. 1977, p. 26.
  11.  Frank Goldsmith, “Coke Ovens, Steel’s Big Demon Wins Again,” New Engineer, Jan. 1977, p. 26.
  12.  Frank Goldsmith, “Coke Ovens, Steel’s Big Demon Wins Again,” New Engineer, Jan. 1977, p. 26.
  13.  Frank Goldsmith, “Coke Ovens, Steel’s Big Demon Wins Again,” New Engineer, Jan. 1977, p. 26.
  14. Bernie Bloom, personal communication.
  15. Ed Greer, “Placebos for a Sick Industry,” The Nation. March 4. 1974; p. 234.
  16. Journal of Commerce, Aug. 19, 1977.
  17. B. Suta, Human Population Exposure to Coke Oven Emissions, USEPA Research, Triangle Park, North Carolina, 1978.
  18. B. Suta, Human Population Exposure to Coke Oven Emissions, USEPA Research, Triangle Park, North Carolina, 1978.
  19. B. Suta, Human Population Exposure to Coke Oven Emissions, USEPA Research, Triangle Park, North Carolina, 1978.
  20. B. Suta, Human Population Exposure to Coke Oven Emissions, USEPA Research, Triangle Park, North Carolina, 1978.