Diesel--the Dark Side of Industry

Dale Lewis’ life went up in a puff of thick, black smoke.

For two days in a row, as he unloaded baggage from jets at Los Angeles International Airport, clouds of soot poured out of a malfunctioning diesel-powered loading machine. For 23 years Lewis worked for airlines, taking pride in hardly ever calling in sick. But now his head ached, his eyes burned and his nose ran. Coughs racked his body. Suddenly he could barely breathe.

Examined by a doctor, Lewis was shocked to learn, according to court documents, that his airways were severely scarred. A specialist told him he was suffering the sudden onset of an unusual respiratory disease, an “industrial asthma,” caused by the intense bouts of diesel smoke exposure.

“An irreversible condition,” the pulmonologist said, “with a poor prognosis.” The fumes had eaten away at the lining of his airways, leaving them so hypersensitive he had to live on oxygen 24 hours a day, confined to his home.

Less than three years later, in 1997, Lewis died at the age of 59--a victim, apparently, of a rare case of death by diesel.

One of the most ubiquitous and perilous pollutants in the nation’s air, exhaust spewed from diesel engines is a potent blend of particles and gases that can inflame the airways, clog the lungs, trigger allergies and even damage genes and induce cancer.

The danger is not just from the sort of sudden, extreme exposure that afflicted Lewis, but from everyday, lower doses as well. Exactly how much the public is endangered and how best to protect people from trucks and other machinery is now among the most contentious issues facing environmental officials.

The state air board last year declared diesel particles a cancer-causing pollutant, triggering a study of possible ways to reduce the health threat. The federal Environmental Protection Agency is considering similar action.

Nowhere is the issue more pressing than in California, where diesel engines--preferred for their reliability and powerful enough to climb mountain passes--drive the state’s economy. More than 4 million Californians suffer from a chronic lung disease. Residents of Los Angeles, Orange, San Bernardino and Riverside counties breathe some of the worst concentrations of diesel fumes in the nation--on average, almost 20 times more diesel particles every day than if they lived in the rural foothills of the Sierra Nevada.

Hot spots--city streets, trucking centers, ports, train yards and freeways--are even worse. Driving to work or standing at a busy intersection exposes Southern Californians to diesel exhaust several times worse than the amount the EPA calls unhealthful. Air along the region’s freeways regularly contains diesel pollution twice as bad as the EPA’s recommended maximum. Some city streets peak at six times higher.

A Population at Risk

Many baffling and controversial uncertainties remain about what precisely diesel exhaust does to human lungs, and the degree of danger people face from regularly breathing it in city air.

Despite the unanswered questions, most health experts believe the risk is real and that this airborne attack is leaving serious casualties.

Asthma attacks, allergies, lung cancer, deaths from heart and respiratory disorders, weakened lung power and difficulty fighting off infections such as bronchitis have all been linked to diesel particles in a series of scientific studies of humans and animals.

“Diesel has very powerful effects on the lung,” said John Froines, director of UCLA’s Center for Occupational and Environmental Health.

Routinely inhaling a concentration of diesel particles found in most urban areas--over 5 micrograms per cubic meter of air--can cause a “spectrum of respiratory problems,” said Charlie Ris, an EPA risk assessment expert.

The people who earn a living operating these pervasive machines, from truckers to rail crews--as well as the families that happen to live near them--face the most danger.

Children appear to be especially vulnerable because they inhale a larger dose of the particles in proportion to their lung size.

Every day across Southern California, people are routinely exposed to high concentrations of diesel’s soot and toxic gases--sometimes even in their own homes.

In the San Bernardino County town of Colton, idling freight trains sent thick clouds of diesel smoke blowing into houses near a track en route to a busy Union Pacific rail yard. Until an order from local air quality officials forbade the idling last summer, parents would not let their children play in the yards, and windows and doors were kept shut. Union Pacific is challenging the order as a violation of its interstate commerce rights.

Also near Colton, schoolchildren breathe diesel fumes in their playground at Grand Terrace Elementary School, which abuts a freeway onramp on Interstate 215 used by trucks at a supermarket distribution center.

Loft dwellers in downtown Los Angeles complain about noisy, dirty trucks carrying fruit and vegetables idling beneath their windows for hours.

In suburban Pico Rivera, Chris Johnson has lived next to a truck company yard for most of his 36 years, his bedroom just 50 feet from the trucks.

Like many people who live near such businesses, Johnson feels powerless and frustrated that no government agency is willing to help. He mostly frets about the annoying noise and road dust. But he can’t help but wonder whether he is risking lung disease from breathing so much exhaust. His father, a smoker who lived in the same house, died of cancer.

“I try to live my life without worrying about dying,” Johnson said, “but of course you have to be concerned.”

Diesels, by design, are dirtier than other engines. Equipped with no sparkplugs, a diesel engine ignites solely by compressing a mixture of fuel and air. Compared with a standard car engine, the mix in a diesel one contains a far higher percentage of fuel. Fine particles of carbon and sulfur remain unburned and are blown out the exhaust. The intense heat and pressure also create nitrogen oxides--a main ingredient of smog.

Today’s diesel trucks and buses, equipped with advanced electronics to control the fuel mixture, are much cleaner than a decade ago. Smog-fighting engine standards set by the EPA and the California Air Resources Board have steadily reduced the volumes of particles from new engines since 1988.

Still, diesels remain a predominant source of air pollution. If every train, truck, bus, tractor, ship and other engine powered by diesel instantly vanished, more than one-third of the nitrogen oxides that form California’s smog and one-fifth of the fine-particle soot would disappear.

Because of formidable engineering challenges and concerns about the economic impact, heavy-duty diesels are not as aggressively regulated as automobiles.

One heavy-duty truck--a typical one, not a particularly smoky one--spews as much soot as 150 average cars. Locomotives are even dirtier, emitting on average of 10 times more soot particles than a truck, according to an Air Resources Board estimate.

Much of the Threat Is Invisible

Although everyone hates being enveloped in the black clouds of smoke behind a bus or truck, it’s the pollutants you can’t see that pose the most danger to your lungs.

Microscopic carbon particles can hover in the air for 10 days. Many times thinner than a human hair, they are readily inhaled, penetrating deep into the lungs, where they stay lodged for weeks or months.

Bound to these particles are traces of hundreds of cancer-causing, petroleum-based chemicals that are carried into the lungs, where they dissolve and spread. One class of compounds, called nitro-PAHs, are such potent gene-damaging carcinogens that, unlike most others, they produce tumors in a multitude of organs in every animal tested.

Scientists theorize that diesel soot works like cigarette smoke--it irritates the airways, and the chronic inflammation can lead to a massive wave of mutated cells.

From routine exposure, people face a cancer threat from diesels comparable to the risk from breathing secondhand tobacco smoke, according to the Health Effects Institute, an independent research group specializing in air pollutants. The danger is low compared with people who smoke, which doubles the cancer risk, but high for cancers linked to pollution.

“Diesel certainly ranks as one of the more potent--and one of the more important--sources of long-term carcinogenic exposure to the public,” said Ron White, the American Lung Assn.’s environmental health expert. “It is probably one of the leading causes of environmental exposures that lead to lung cancer.”

Experts suspect that fewer than 2% of cancers are caused by environmental factors, but in a population as large as California’s, that can still translate into thousands of people. A state panel of scientists says four of every 10,000 Californians could contract cancer from breathing diesel fumes in average outdoor air. Overall, they estimate that 14,000 Californians alive today will die from lung cancer caused by diesel exhaust.

The estimate, however, is imprecise and highly controversial because it is extrapolated from cancer rates among railroad workers, truckers and others exposed to larger doses of fumes.

While the risk of cancer is the attention-grabber, for a majority of people the most prevalent threat is allergies and asthma, said Dr. John Balmes, chief of San Francisco General Hospital’s division of occupational and environmental medicine.

Diesel particles seem to aggravate--and may even cause--allergic reactions and asthma attacks in people who inherited certain genetic traits, Balmes said.

When diesel particles equivalent to breathing Los Angeles air are applied inside the noses of people with allergies, immune cells are triggered and there is a 50-fold surge in the antibodies that cause allergy symptoms, according to UCLA School of Medicine immunologist Andrew Saxon.

The UCLA research and animal studies in Japan suggest that diesel may be one of the culprits behind an alarming increase in asthma and hay fever. One of every five Americans suffers allergies, and asthma rates among U.S. children have soared over the last 20 years, reaching epidemic proportions.

Also, deaths from lung and heart ailments have been linked to fine soot particles that come not just from diesel, but from any fuel combustion. Whenever particles in the air increase, deaths and hospitalizations rise, according to several dozen studies of U.S. cities.

“We are now finding, more and more, that lower levels of particles can cause significant health concerns, ranging from premature death to aggravation of asthma,” said White of the lung association.

Machine Operators Face Most Serious Risk

The 4 million Americans who operate diesel machines on the job face the most serious risks.

Their chances of dying from lung cancer rise 20% to 40% compared with the general population, according to a Health Effects Institute review of about 40 studies by epidemiologists. While five of every 100 people in the general population contract lung cancer from smoking and other factors, another one or two are expected to get it from diesel exposure at their jobs.

At the Ports of Long Beach and Los Angeles--massive operations that are filled with trucks, ships, trains and cranes--workers breathe some of the most severe doses of diesel exhaust found anyplace in California.

On busy days, the seaside air is tinged a dingy gray, with a hundred or more big rigs backed up at each of the two harbors.

One typical afternoon at the Long Beach port, Mike Nichols stood beside his big rig, engine running, as he waited to drop off a load of cargo destined for overseas. A dozen trucks like his were lined up, most of them so old or badly maintained that black soot poured out in long, billowing streams.

Nichols and the other truckers breathe the fumes for hours at a time as they wait for ships to load or unload cargo containers.

“That stuff’s bad,” said Nichols, who has driven trucks for 15 years. “It makes me nauseated and dizzy and sleepy. When I get home, I have to sleep it off. It feels like my body is buzzed. Like I’ve been drugged.”

Wes Brickner, a marine clerk at the Port of Los Angeles, remembers one especially bleak day when a ship stoked its stacks for more than an hour. Winds blew the soot up, straight at workers sitting in the cabs of gigantic cranes unloading the cargo.

“There was a big cloud over the harbor, and it was just sitting there,” Brickner said. “It just makes you sick to think about it. You’re exposed, you’re breathing it, you’re tasting it. You get headaches and stuff from it.”

Studies show that truck cabs contain the same amount of carbon particles as the surrounding highway air. But because truckers spend more time on highways than the general population, they probably breathe more pollutants into their lungs.

In one federal study, truckers with more than 35 years on the job faced an 89% increase in lung cancer compared with the general public. The study controlled for both smoking and diet.

A Harvard University study that tracked 55,000 railroad workers who died before 1980 found that their cancer rate increased with years of exposure--those with more than 15 years on the job had a 72% greater rate of dying from lung cancer than the general population.

Yet many truckers and their employers remain skeptical.

“If there’s an epidemic of cancer in our industry, where are the bodies?” asked Mike Applegate, owner of a trucking company in Sacramento. “I’ve never had a trucker die of lung cancer.”

Many cancers, however, have a 20-year latency, and the use of diesel has grown dramatically only in the last generation. Because of that, many workers may not fall ill until well into retirement.

If the cancer risk is true, added Applegate, “we would need some serious changes. We’re not making that much money. It’s not worth it.”

Engine manufacturers and trucking companies question the veracity of the studies, calling them flawed and outdated. In most cases, the workers were exposed several decades ago, when exhaust was dirtier, and the researchers lacked important data about how much the people actually inhaled.

Aaron Cohen of the Health Effects Institute and Millicent Higgins of the National Institutes of Health found “a paucity of data on exposure and potential confounding [factors]” that makes the worker studies “difficult to interpret,” they said in a 1995 report.

Still, Froines said, “the evidence around the human studies is extremely strong and consistent.”

Daniel Greenbaum, president of the Health Effects Institute, said about 40 studies have been conducted and “they all, almost every one of them, show a positive association” between diesel and cancer in workers. The institute, funded by the EPA as well as the automobile industry, is considered a leading, unbiased source of data on the hazards of air pollution.

Efforts to understand the health danger are complicated by the complex makeup of diesel exhaust.

It remains a mystery as to which of the thousands of chemicals in diesel exhaust makes people sick or how it inflicts its damage--critical questions for public officials trying to protect people. Some health officials suspect that the size of the individual particles determines the damage, not necessarily what they are made of.

Other arguments remain about what the higher cancer rate for workers means for the general public. Can the risks of working on a freight train for 20 years be scaled back to gauge the danger to people who occasionally drive behind trucks on freeways or live near a rail yard? Is there a level where there is no risk at all?

USC epidemiologist John Peters called it a “classic threshold question that may never be answered.”

The diesel industry has strongly rejected the idea that their engines can be linked to cancer. “Before you say ambient air causes cancer, you should be very certain, and we don’t think that the evidence is there,” said Dr. William Bunn, medical director of Navistar International, one of the largest diesel engine manufacturers.

Independent scientists agree that the estimates of the level of cancer risk are controversial. “Diesel exhaust is a carcinogen,” said Balmes of San Francisco General, and workers “are at risk.” What is less clear, he said, is “whether ambient levels are leading to a cancer problem in the general population.”

Workers generally breathe exhaust “an order of magnitude [10 times] higher than what you or I would get on the street,” Greenbaum said.

Froines defends his panel’s conclusion that the general public faces a serious cancer risk from diesel exposure. To assume there is no cancer at doses people routinely breathe “ignores basic chemical facts” about the human body, he said.

“I believe there are different [cancer rates] at different doses, but the risk to the general population is not zero,” he said.

Despite the uncertainties, after nine years of debate and delays, the state air board last year followed its scientific panel’s advice and declared diesel particles a cancer-causing pollutant.

Former EPA assistant administrator Dick Wilson said, “Whatever the risk [of diesel] is today, it’s way down and will continue to go down.” Still, he said, “we are concerned about the health reports showing it’s toxic.”

The new, and rare, phenomenon of severe lung illnesses being directly linked to diesel exposure adds some urgency to the call for action. In the last few years, health experts have uncovered a handful of such cases.

At LAX, two days of breathing heavy diesel exhaust combined with years of exposure apparently turned deadly for Dale Lewis. Dr. Mohan Khurana, a Torrance pulmonologist who treated him for three years until he died, said in a 1997 court declaration that the diesel exhaust ate away at the lining of Lewis’ airways, “causing an extreme hypersensitivity.” His airways constricted so tightly whenever he encountered airborne irritants that he was left unable to breathe on his own.

Before he died, Lewis sued the maker of the container loader, alleging that the machine was designed with an improper exhaust system. His widow, who declined to talk to The Times, settled for an undisclosed amount of damages last year.

Pulmonologists uninvolved with the Lewis case say there are only a few documented examples of asthma induced by diesel exhaust.

In 1993, scientists at the National Jewish Center for Immunology and Respiratory Medicine in Denver reported that three railroad workers contracted sudden, severe asthma from riding in locomotives right behind the lead engines of freight trains. Like Lewis, all three were healthy until a severe exposure at work that persisted many hours.

Such diseases, sometimes called irritant-induced asthma, “are rare, and death due to it is very rare,” said Balmes of San Francisco General Hospital. Still, he said, “it is conceivable. I think it’s real.”

Union leaders say few truckers and other workers complain about diesel fumes, believing the danger simply comes with the job. But trucker Mike Nichols wonders if he can stand it much longer.

“It’s the sickness, the exhaust,” he said. “If it’s not my truck, it’s all the others.”

*

Next: Cleaning up diesel pollution is difficult but possible.

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

Sources of Diesel Exhaust

Statewide tons of diesel particulates in 1995

Trucks 54%

14,280 tons

Construction equipment: 19% - 5,010 tons

Ships/boats: 10% - 2,770 tons

Farm equipment: 7% - 1,870 tons

Trains: 4% - 1,090 tons

Stationary engine/mobile refrigeration units: 4% - 950 tons

Cars and buses: 2% - 590 tons

Source: California Air Resources Board

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

How a Diesel Engine Pollutes

A diesel engine has several unique characteristics that make it an efficient and durable technology--and a major source of air pollution. It has no spark plugs; instead the fuel is ignited through pressure. Also, it has a very high ratio of fuel to air during combustion--more than 20 times more fuel than air.

Diesel fuel is pumped into the computerized injector that inserts fuel into the cylinder at a very high pressure so it is atomized into a fine mist.

Air is forced through the turbocharger into the cylinder, where it mixes with the fuel.

The piston rises up, compressing the air and fuel to create an explosion--combustion--at temperatures exceeding 1,500 degrees.

The explosion pushes the piston down, which turns the crankshaft and ultimately moves the truck.

Toxic hydrocarbons, soot particles and other compounds come out the exhaust pipe. Because of the extreme pressure and heat in the engine, nitrogen and oxygen react, forming nitrogen oxides--a major ingredient in smog. Also, because so much fuel is injected, some is left unburned, leaving fine particles of sulfur and carbon that spew out of the exhaust pipe.’

Source: Cummins Engine Co. and California Air Resources Board