Diesel Exhaust & Cancers-Long Term
Railroad Exposures Linked to Diseases and Cancers
Published: May 5, 2008
This article discusses railroad worker long term diesel exhaust fume
lung disorders, as well as medical studies relating to diesel fume lung
diseases and lung cancers, and another related article in this series
covers new federal regulations that are clamping down on excessive
railroad locomotive engine diesel fumes, as well as historical knowledge
and diesel exhaust lung disease legal cases against railroads such as
CSX and Norfolk Southern over the last several decades.
There is a growing body of evidence that long-term railroad worker exposure to diesel exhaust fumes can lead to a condition called "diesel asthma" a form of COPD, and additional evidence shows an increased incidence of lung cancer rates among railroad workers/employees. Railroad worker injury claims against their employer-railroads fall under a federal act called the Federal Employers Liability Act. This article discusses railroad worker long term diesel fume lung disorders, as well as medical studies relating to diesel fume exposure, and another related article in this series covers new federal regulations that are clamping down on excessive railroad locomotive engine diesel fumes, as well as historical knowledge and legal cases against railroads such as CSX and Norfolk Southern over the last several decades.
What is diesel smoke or diesel exhaust fumes?
Diesel exhaust, also called diesel smoke or diesel fumes is a chemical mixture containing literally hundreds of compounds, including sulfur dioxide, nitrogen oxides, poly-systematic hydrocarbons, benzene, and many other compounds. Many of these individual particulates are known carcinogens, and have been known cancer-causing agents for over 30 years. In the railroad industry, diesel fuel runs nearly all locomotives, and has since the 1960's. When the diesel fuel is combusted, the chemicals change. They are changed into a gaseous state, and they are carried through the air by what are known as particulates. Particulates are the part of diesel exhaust fumes and diesel smoke that can be seen. But some particulates are so small that they cannot be seen and some of these get into the tiniest part of the lung tissue, deep in the lungs. Some of these dangerous chemicals can damage, inflame and destroy lung tissue. Also, the irritation over time can cause "hypersensitivity" disorders.
According to a scholarly 2001 American Cancer Society medical article (also published at CA Cancer J Clin 2001; 51:193; doi: 10.3322/canjclin.51.3.193), authored by Doctors Howard Frumkin and Michael Thun:
While diesel engines can operate with less highly refined fuel and consume less fuel per unit of work performed, they typically emit more particulate mass than catalytically equipped gasoline engines. Diesel engines are the predominant source of industrial power throughout the world for engines up to about 5,000 horsepower. A much larger percentage of passenger vehicles in Europe are powered by diesel engines than in the US.
The exhaust from diesel engines consists of both gas and particulate fractions, each of which is composed of thousands of different substances. The gas portion of diesel exhaust contains primarily carbon dioxide, carbon monoxide, nitric oxide, nitrogen dioxide, sulfur oxides, and hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs). PAHs are produced as pyrolytic products during the combustion of any fossil fuel, including diesel fuel.
The particulate portion of diesel exhaust, also known as soot, is mainly composed of elemental carbon, organic material (including PAHs), and traces of metallic compounds. Thus PAHs are found in both the gaseous and particulate fractions of diesel exhaust.
Emissions of organic compounds from gasoline (both leaded and unleaded) and diesel engines are qualitatively similar, but there are quantitative differences. Older, light-duty diesel engines (automobile and light trucks), for instance, can emit 50 to 80 times more particulate mass, and heavy-duty diesel engines emit 100 to 200 times more particulate mass than catalytically equipped gasoline engines, although the difference has decreased substantially with newer models. Gasoline engines without catalytic converters produce a similar quantity of PAHs compared with diesel engines.
There are a number of railroad worker jobs that can expose workers to repeated and continuous diesel fume exposure, including brakeman, switchman, engineer, conductor, diesel engine and locomotive repair shop workers and carman/car repair workers, to name the most obvious. This type of work, over many years, can lead to various types of lung diseases and lung disorders, including aggravation to chronic obstructive pulmonary disease conditions (COPD), aggravated asthma, and in some cases exposure has been linked to cancer.
Workers have described, over many decades, how diesel exhaust fumes and diesel smoke can be seen, can be felt (while breathing), and can even be tasted, on the tongue after prolonged exposure. But most railroad workers are not aware of the long term, permanent lung disease associated with this toxic exposure.
Where and how are railroad workers exposed?
With regard to railroad engineers and conductors, many describe exposure to diesel fumes as occurring in locomotive engines, even though this is a place that should not have diesel fumes. Properly functioning railroad locomotive engines should deposit all diesel exhaust fumes outside an engine cab, but over many years it has been shown that the engine exhaust stack location has not prevented the fumes from entering a large number of engine cabs--based on methods of locomotive use and based on exhaust stack height or location. For example, air conditioning was not available and is still not available in many types of railroad engines. Many locomotive engines were normally operated with windows opened, because of the extreme heat inside and also to afford an engineer or conductor a better view of ground operations by looking out the side window of the cab. Many types of older yard and switching engines actually were run in the long hood forward orientation. In many yard and switching engines, this meant that the diesel exhaust stack was in a position forward of the engineer cab. As the engine moved forward, this would stream the diesel fumes back toward the open windows of the engine cab.
Also, during the 1980's/early 1990's, Norfolk Southern and some other railroads used various diesel engines in the long hood forward position for decades, until union members and workers repeatedly complained about the diesel exhaust fumes and the health effects of repeatedly breathing the fumes. The problem for Norfolk Southern was that the engineer console was set up to run long hood forward, therefore Norfolk Southern was going to be required to modify its engines and/or to modify the locomotive exhaust stacks to prevent the streaming of the diesel fumes into the cab, and this would cost money. Eventually, NS made the modifications and the long hood forward cab engine issue partially was resolved involving one class of engine.
Workers with virtually every major railroad involved in rail yard switching or industry switching have worked with older engines affectionately called "butthead" engines, many manufactured in the 1950's by EMD (General Electric and EMD are presently two of the major diesel locomotive manufacturers in the U.S.. These yard switcher butthead engines were manufactured by EMD and many of these engines were called "smokers." Many variations situated the engineer on the right side of the engine cab, with the long hood forward, and this placed the diesel exhaust stack or pipe right in front of the cab, at a height fairly near the top of the cab-the engineer would face this stack in normal forward operations. This meant in long hood forward moves, that the exhaust trailed right back toward the cab and most times the windows were opened due to lack of closed ventilation or air conditioning. How long were these butthead switchers used? For decades. Some of the 1950's EMD engines are still in operation.
Car repair/carmen, with many railroad such as CSX, Norfolk Southern (NS/N & W) and Amtrak, worked inside of shops or tunnels, where ventilation was less than ideal to say the least. Even for workers not situated inside the engine cab, constant and repeated work in a poorly ventilated area around idling locomotive engines exposed these workers to significant diesel exhaust fumes over many years. This type work exposure can always be aggravated by significant work spent inside tunnels or mostly in closed areas such as shops.
What should railroads do to protect railroad workers?
According to industrial hygiene and industrial safety specialists, there are at least four different methods to control exposure to diesel exhaust fumes: 1) engineering controls should be implemented, such as isolation areas, appropriate shelters for employees, or actual engineering changes to equipment that subjects workers to diesel exhaust fumes, and this could include changing diesel exhaust stacks on engines to assure that fumes do not trail into locomotive engine cabs, providing air conditioning and/or pressurizing and sealing engine cabs so that fumes will not enter the cabs through openings, etc.; 2) implementing administrative controls, which means rotating a railroad worker in and out of a particular job that might expose the worker to excessive diesel exhaust ; 3) changing work practice controls, which means choosing the manner of doing a particular job so as to minimize exposure to diesel exhaust hazards; and 4) mandating personal protective equipment such as masks or respirators or other similar protective equipment. All of these principles are typical industrial health and safety controls, not only in the railroad industry, but for general industry.
A related health and safety practice, is to monitor the workplace-meaning to do air samples and air tests. Air testing has been a routine part of industrial health and safety since as early as the 1930s. Some railroads and or some state or federal inspectors have done air testing for various toxic substances earlier than even 1950. This author's research has shown the railroads occasionally did air testing for various toxic substances, but were very mindful that if the test returned a toxic air result above an acceptable limit, this could provide worker evidence to support claims. Accordingly, at least after the 1970s, the nation's major railroads were extremely careful as to who they allowed to do any air testing, anywhere on railroad property, including locomotive engines. Typically, railroads such as CSX and Norfolk Southern carefully selected "friendly" industrial safety experts that they knew they could count on to advocate their side. Railroad lawyers representing workers in the last 15 to 20 years have discovered that several of the industrial health and safety experts retained by railroads have testified literally hundreds of times, always on behalf of railroad defendants in injury lawsuits. Naturally, we do not believe that testing is valid when presented by an expert who has been paid by the railroads to do the testing, and who is again paid handsomely to testify on behalf of railroads in court hundreds of times.
Cancers and Prolonged Diesel Exhaust Fumes Exposure
In September 2002, under the Bush Administration, the EPA added that "long-term exposure to diesel engine exhaust (DE) in the air is linked to lung cancer. The human evidence from occupational studies is considered strongly supportive of a finding that diesel exhaust exposure is causally associated with lung cancer, though the evidence is less than that needed to definitively conclude that diesel exhaust (as a whole) is carcinogenic to humans," the EPA report said. "Overall, the evidence for a potential cancer hazard to humans resulting from chronic inhalation exposure to [diesel emissions] is persuasive," the report said. Earlier reports said that diesel truck drivers, mechanics, and people whose occupations expose them constantly to diesel exhaust have higher lung cancer rates. But the 2002 EPA report focused on those who breathe diesel exhaust in the air around them, whether they work directly with diesel engines or not.
However, the EPA, after 2002, delayed implementing the new regulation due to suits by the distributors of diesel fuel. The air-cleaning regulation was delayed when oil refiners sued the EPA to stop it, but eventually a federal appeals court ruled the EPA could go ahead and the agency said it would do so, according to news reports.
Epidemiology includes the scientific study of statistics and medical causes. According to Frumkin & Thun's 2001 medical journal study/article, prolonged diesel exhaust fume exposure has been linked to increased lung cancer rates, per this excerpt:
The major cancer suspected of being linked to diesel exhaust is lung cancer. Epidemiologic studies of lung cancer risk in diesel-exposed workers are affected by the usual challenges of epidemiologic studies, especially the difficulty of correctly defining and quantifying occupational exposure, and confounding by other exposures such as smoking and concurrent workplace exposures.
Epidemiologic studies of workers exposed to diesel exhaust have shown small but significant elevations in risk of lung cancer. A case-control study found that railroad workers with at least 20 years of service were significantly more likely to die from lung cancer than were members of the general population. A cohort study of over 55,000 railroad workers by the same researchers found that lung cancer risk increased with duration of exposure to diesel exhaust; the relative risk was 1.72 among workers with the longest exposure (as much as 22 years).
Several studies of teamsters also linked diesel exhaust exposure with lung cancer. Still another study analyzed the lung cancer incidence of almost half a million American males in relation to their occupational exposure to diesel exhaust; men with the heaviest and most prolonged exposures, such as railroad workers, heavy equipment operators, miners, and truck drivers, had higher lung cancer mortality than unexposed workers.
Also, the International Agency for Research on Cancer (IARC) studies exposures that may be cancer causing/carcinogenic. This organization classified diesel exhaust as "probably carcinogenic to humans."
The Environmental Protection Agency (EPA) uses a classification system very similar to that of the IARC. EPA considers diesel exhaust "likely to be carcinogenic to humans by inhalation at any exposure condition."
The National Institute for Occupational Safety and Health (NIOSH) recommends that "whole diesel exhaust be regarded as a potential occupational carcinogen as defined in the Cancer Policy of the Occupational Safety and Health Administration (OSHA.)"
How long have railroads known of the dangers?
The nation's railroads, such as Norfolk Southern, CSX and Amtrak, as well as the other major railroads, participate in a national research and trade organization known as the Association of American railroads (AAR). An affiliated organization is called the medical and surgical section of the AAR, allowing the railroad staff medical doctors to exchange information and have seminars-the physicians met annually as early as the 1930's. Likewise, there is yet another affiliated organization of the claims representatives of the nation's railroads, allowing these staff to exchange information and hold educational meetings and seminars. As early as the 1950s, the claim representatives of the railroads were discussing the health effects of diesel exhaust fumes. Historical documents have shown that these doctors and claims representatives discussed railroad worker claims relating to diesel exhaust fumes, and that discussions of the health effects was covered in detail.
In 1955, a railroad industry attorney gave a formal presentation to the major railroad claims representatives. The attorney, Robert Straub, was employed at the time with the Chesapeake and Ohio Railways Company, which was at a later date folded into CSX. The presentation was entitled "potential dangers from exposure to diesel locomotive exhaust." Referring to the gases that made up diesel exhaust, Straub stated "it appears that continuous or prolonged exposure to atmospheres containing any of the above mentioned gasses in excess of the established maximum could initiate harmful results." He noted that availability of "atmospheric testing" could help determine the degree of hazard to which workers were exposed. Straub went on to state that he had completed a survey of the majority of the railroads and as of 1955 had found a total of six cases involving diesel fume exposure, and he categorized the jury verdicts as between 18,000 and $19,000. He categorized the payments as relatively unimportant and stated that "from a claim and law standpoint, this field has been relatively unimportant...."
Several years later, in 1961 the same AAR railroad industry organization, the claim agent's subsection, published an article in its journal mailed nationwide to its members, called The Bulletin (volume 46, number 10), reporting on a notable legal decision involving the Missouri Pacific Railway Co. and a pipefitter's injury claim against Missouri Pacific. The appeal involved a personal injury verdict in favor of Mr. Sims, a Missouri Pacific pipefitter, and the case outlined that the pipefitter contended that because of alleged insufficient ventilation in the shop, he suffered injuries from inhaling the diesel fumes and gases given off by railroad locomotives. He complained about the harmful effects on his body upon being required to work in a place where diesel fumes were concentrated in large quantities.
In 1965, the nation's railroad medical doctors had their annual seminar, and the seminar discussions were transcribed. The annual meeting was moderated by Dr. Kaplan, a Baltimore in Ohio Railway Co. staff physician (this railroad was later folded into CSX). The dangers of diesel fumes and the potential association of diesel fumes with cancer was a topic of discussion at the annual meeting.
By 1971, the Occupational Safety and Health Administration was created in the U.S.. During the 70s and 80s, OSHA enacted a large number of workplace protective regulations pertaining to respiratory protection, workplace protections in general and the communication to workers of hazards relating to toxic substances.
Around the same time, the National Institute for Occupational Safety and Health (NIOSH) issued what it called Intelligence Bulletin 50 setting forth many of the dangers of diesel exhaust fumes, as established by many peer reviewed scientific and medical studies reporting on adverse health effects of prolonged diesel exposures. A study by NIOSH is typically widely distributed to general industry including railroads.