The science linking diesel exhaust to serious illness, including lung cancer and bladder cancer, has been building since the 1950s. The railroad industry was not on the outside looking in — it was in the meetings when these dangers were first discussed. So, it had every reason to act long before most workers were ever protected.
Why This Matters Legally
Under the Federal Employers Liability Act (FELA) — the federal law that protects railroad workers — a railroad can be held responsible if its negligence played any role in causing a worker’s illness.
One of the key building blocks of a FELA claim is notice: did the railroad know, or should it have known, that diesel exhaust posed a health risk to its workers? When it comes to diesel exhaust, that question has a clear answer.
The railroad industry’s own internal records, medical meetings, and decades of published scientific research show that railroads knew about the hazard long before most workers were warned or protected. That history of knowledge is central to holding railroads accountable.
A Timeline: What the Railroads Knew and When
1955: The Railroad Industry Discusses Cancer and Diesel Exhaust
The railroads transitioned from coal-burning steam locomotives to diesel locomotives in the years following World War II. In May 1955, the General Claims Division of the Association of American Railroads held a meeting in Washington, D.C. An attorney for one of the major railroads stood up and addressed the group on what he called the “Potential Dangers from Exposure to Diesel Locomotive Exhaust.”
His presentation listed cancer-causing substances — which he called “cancerogens” — among the important components of diesel exhaust gases. He noted that the National Cancer Institute, in conjunction with the Railroad Retirement Board and several railroad labor organizations, had already launched a study to explore the link between diesel exhaust and lung cancer. He warned that the cancer-causing potential of diesel exhaust “cannot be overlooked.”
So in 1955, in their own meeting room, railroad representatives were discussing the possibility that their workers were breathing cancer-causing substances, and talking about how to defend against future lawsuits.
The 1950s: Science Confirms Diesel Exhaust Is Potentially Carcinogenic
The railroad industry’s internal discussions were consistent with what scientific researchers were finding at the same time. As early as 1955, published studies showed that the black soot produced by inefficiently operating diesel engines contained significant amounts of cancer-causing compounds. Animal studies demonstrated that exposure to diesel exhaust extracts produced tumors, leading researchers to describe diesel exhaust as a carcinogen of “high potency.” By the late 1950s, researchers had also confirmed that diesel exhaust was a significantly greater source of harmful hydrocarbon pollution than gasoline engine exhaust.
1962: Benzene Identified as a Component of Diesel Exhaust
A 1962 study of diesel exhaust composition found that diesel engines actually produce more benzene in their exhaust than is present in the fuel itself. Benzene is a chemical that causes cancer in humans, including leukemia and bladder cancer. Its presence in diesel exhaust meant that railroad workers breathing diesel fumes were also being exposed to a known human carcinogen, whether anyone told them or not.
1965: The Railroad Industry Holds a Panel on Diesel Exhaust and Lung Cancer
By 1965, the Association of American Railroads was devoting an entire panel discussion at its annual medical meeting to the connection between diesel exhaust and lung cancer. The moderator opened the session by telling the assembled railroad medical officers that “the railroad industry is also becoming implicated as possibly being a factor in lung cancer because of diesel exhaust fumes,” and that “more and more litigation in this field is being presented.”
The panel discussed the carcinogenic potential of certain diesel exhaust compounds. It distributed a report on pulmonary diseases in the railroad industry. It acknowledged that the problem was “indeed a vital one to the railroad industry and well worth investigating.”
This was the railroad industry’s own medical leadership telling itself that diesel exhaust and lung cancer were a serious, growing problem.
1970: The Federal Government Draws a Hard Line on Carcinogens
In 1970, a federal committee reported directly to the U.S. Surgeon General that no level of exposure to a chemical carcinogen should be considered safe for humans. Also, any substance shown to cause tumors in animals should be treated as a potential cancer hazard for people. That same year, Congress created the Occupational Safety and Health Administration(OSHA) and established the General Duty Clause, which requires every employer to provide workers with a workplace free from recognized hazards likely to cause serious harm or death.
1977 and 1978: Federal Agencies Flag Diesel Exhaust Health Risks
The Federal Railroad Administration published reports in 1977 and 1978 examining diesel exhaust exposure among railroad workers. Although those reports downplayed the risks and relied on flawed studies, they still showed that the federal government and railroad industry were actively studying the health effects of diesel exhaust exposure.
1979: Benzene Confirmed as a Human Carcinogen
International health researchers confirmed in 1979 that benzene causes cancer in humans. Since benzene had already been identified as a component of diesel exhaust, this finding meant that railroad workers exposed to diesel fumes were being exposed to a confirmed human carcinogen. By this point, the only honest question was not whether diesel exhaust was dangerous — it was what the railroad industry intended to do about it.
1987 and 1988: Harvard Researchers Prove the Link to Lung Cancer in Railroad Workers
In 1987 and 1988, researchers at Harvard University Medical School published landmark studies examining lung cancer rates among railroad workers specifically. Researchers analyzed the death records of tens of thousands of railroad workers and found that those in diesel-exposed jobs for 20 or more years had a significantly higher risk of lung cancer — even after accounting for smoking and other factors.
The 1988 study evaluated over 55,000 railroad workers. The U.S. Environmental Protection Agency (EPA) later described it as a large, well-designed study with meaningful findings. These were not studies of industrial workers in general. They were studies of railroad workers, doing railroad work, breathing diesel exhaust on the job.
1988: The Federal Government Officially Declares Diesel Exhaust a Potential Carcinogen
Also in 1988, the National Institute for Occupational Safety and Health (NIOSH) published an official bulletin recommending that diesel exhaust be regarded as a potential occupational carcinogen. NIOSH called on employers who used diesel-powered equipment to inform their workers of the new findings and to implement all available controls to minimize exposure. The railroad industry was on the list.
1998 and 2002: Federal Agencies Confirm Diesel Exhaust Likely Causes Cancer in Humans
In 1998, federal scientific panels formally identified diesel exhaust as a toxic air contaminant. In 2002, the EPA concluded that diesel exhaust is “likely to be carcinogenic to humans by inhalation,” based on human studies, animal studies, and the broader body of supporting science.
2012: The World’s Leading Cancer Research Agency Calls It Certain
In 2012, the International Agency for Research on Cancer (IARC) — part of the World Health Organization — reclassified diesel exhaust as a Group 1 carcinogen, meaning the evidence that it causes cancer in humans is sufficient and no longer a matter of scientific debate. The specific cancer confirmed was lung cancer.
What the Railroads Could Have Done Differently
The science was not the only thing available — practical tools for reducing diesel exhaust exposure have existed for decades. Reducing unnecessary locomotive idling — which was identified as the single largest source of certain diesel emissions — could have been implemented with minimal cost and was discussed as early as the 1970s.
Air conditioning in locomotive cabs, which prevents workers from having to ride with windows open in exhaust-heavy environments, was available and in use on some railroads by the 1970s. Filtration systems capable of dramatically reducing diesel particulate levels in enclosed spaces have been available and used in other industries for decades. Respiratory protection, engineering controls, and proper ventilation in shops and roundhouses were all recognized industrial hygiene tools long before most railroad workers received any protection at all.
Federal regulations specifically require that enclosed cabs on ballast regulators, tampers, mechanical brooms, and similar maintenance equipment be equipped with air conditioning and positive pressure ventilation systems capable of protecting workers from air contaminants. The law has recognized the problem. The question is whether individual railroads acted on that obligation or ignored it.
What This Means for You
If you worked around railroad diesel exhaust and have been diagnosed with lung cancer, bladder cancer, or another diesel-related illness, the timeline above matters to your case. The railroad that employed you had access to this information. Its own medical leadership was discussing the cancer risks of diesel exhaust while many of today’s retired workers were still early in their careers.
A railroad diesel exhaust injury attorney can review whether the railroad failed to warn you, failed to protect you, or failed to take reasonable steps to reduce your exposure to a substance it knew was dangerous.
Under the FELA, the railroad does not have to be the only cause of your illness. If its negligence contributed to your diagnosis in any way — even a small role — you may be entitled to compensation.
A railroad may have been negligent if it:
- Failed to warn you that diesel exhaust was linked to cancer
- Allowed you to work in enclosed spaces or locomotive cabs with inadequate ventilation
- Did not provide respiratory protection when diesel exhaust levels were elevated
- Failed to reduce unnecessary idling in areas where workers were present
- Failed to properly maintain air conditioning and air filtration systems on its on-track equipment and locomotives
- Knew about the hazard from its own internal records and did nothing
Frequently Asked Questions
What is railroad diesel exhaust and why is it dangerous?
Diesel exhaust is the complex mixture of gases and fine particles that comes out of a diesel engine. It contains thousands of chemical compounds, including many that are known or suspected to cause cancer. Among them are benzene, formaldehyde, benzo[a]pyrene, and dozens of other harmful substances. Long-term breathing of diesel exhaust has been linked to lung cancer, bladder cancer, and other serious diseases.
When did the science on diesel exhaust and cancer become clear?
The concern about diesel exhaust and cancer began in the 1950s and grew steadily through the following decades. By 1988, the federal government had officially labeled diesel exhaust a potential human carcinogen. By 2012, the world’s leading cancer research organization concluded that the evidence was sufficient to call it a definite human carcinogen. The railroad industry had access to this developing science at every stage.
Did the railroad industry know about the health risks before workers were warned?
Yes. The railroad industry’s own internal medical meetings were discussing the cancer risks of diesel exhaust as early as 1955. By 1965, railroad medical officers were holding panel discussions specifically on diesel exhaust and lung cancer. This is not a situation where the science arrived without warning — the railroads were part of the conversation from the beginning.
What railroad jobs involve diesel exhaust exposure?
Almost all railroad work involves some exposure to railroad diesel exhaust, especially jobs performed in or around locomotives, rail yards, shops, and diesel-powered equipment. Common examples include:
- Engineers and conductors who ride in locomotive cabs
- Shop workers who service locomotives in enclosed buildings
- Maintenance of way workers who operate diesel-powered equipment on the track
- Yard workers who spend shifts around idling locomotives
- Hostlers, switchmen, carmen, and other workers who work in and around diesel-powered machinery
Does it matter if I smoked?
Not necessarily. Under the FELA, the railroad’s negligence only needs to have played some role in causing your illness. Research has also shown that the combination of diesel exhaust and cigarette smoke is more dangerous than either exposure alone. A smoking history does not eliminate the railroad’s potential liability for a worker’s diesel exhaust exposure.
If you or a family member worked for a railroad and has been diagnosed with lung cancer, bladder cancer, or another serious illness, contact Hughes Law Offices for a free consultation. We represent railroad workers nationwide.
Call us at (312) 877-5588. Your consultation is free, there is no obligation, and there is no attorney fee unless we recover compensation for you.
