It’s in the air we breathe. Diesel exhaust contains at least 40 toxic air contaminants, plus soot particles so small that they bypass filters in the human body. And it’s everywhere in urban air. Some people breathe more of it than others. Millions of American workers are exposed at work to diesel exhaust — truckers and loading dock workers, obviously, but also longshore, maritime, and railroad workers, school and city bus drivers, firefighters, construction workers, and others who work near heavy equipment.

The good news, for breathers, is that new heavy-duty trucks and buses have some of the cleanest engines in the world, thanks to Environmental Protection Agency rules that took effect in 2007. These new diesel engines are so clean that the air coming out the tailpipe is cleaner than the air that went into the engine — in polluted locales like Los Angeles, anyway.

The “bad” news is that diesel engines are incredibly durable. That means a “legacy fleet” of dirty older-model diesel engines is likely to be putting worker health at risk for decades to come. There’s a tow boat on the Columbia River, for example, that still runs on an engine pulled out of a World War II submarine. These engines stick around.

So it’s the job of one union member — Kevin Downing — to persuade owners of diesel engines to take measures to reduce exhaust sooner rather than later. Downing coordinates the Oregon Clean Diesel Initiative at the Oregon Department of Environmental Quality (DEQ), and is a former president of Local 3336 of the American Federation of State, County, and Municipal Employees.

“It takes a certain amount of convincing,” Downing said, “because I really can’t guarantee there will be fewer people sick on job, and I can’t guarantee they’re going to see reductions in their health insurance premiums. But there are tremendous benefits to the community at large.”

The medical evidence, Downing says, is convincing.

“Diesels always have had a reputation for being smoky and smelly,” Downing said. “But now, what we’re discovering through advances in medical research is that particulates are more than a nuisance; they are a health concern. There’s increased risk for lung cancer, cardiovascular disease, asthma, bronchitis, and other health effects.”

“We can’t predict on an individual basis who will experience these health effects,” Downing said. “But we can say that generally with increasing exposure to diesel, we see increasing incidence of [the diseases].”

Part of the problem is that carcinogenic chemicals produced when diesel fuel combusts “stick” to the soot particles in the exhaust, and those particles are small — 2.5 microns in diameter, one-hundredth the width of a human hair. The particles are so small that they can’t be trapped by nose hair or swept out by cilia cells that line the windpipe. They enter the lungs and go directly into the bloodstream, where they affect the metabolism of cells, causing inflammation and blood clotting that can lead to heart attacks.

Non-road diesel engines are the dirtiest. In Oregon, Downing said, construction equipment represents as large a segment of the total contribution of diesel particulates as all the over-the-road trucks. Cleaner, low-sulfur diesel fuel is required for diesel engines on the highways, but not yet for off-road diesel engines like heavy construction equipment.

“Nobody disputes that there’s a problem with exhaust from diesel engines,” Downing said. “It’s just that for many folks, it’s like ‘tomorrow’s another day, and I’ll worry about it then.’”

One hurdle is that it can cost $1,200 to $12,000 per vehicle to install the filters and catalytic converters that reduce harmful exhaust. However, there are federal grants available to help with that, Downing said, and Oregon has state business income tax credits that reimburse half the cost of replacing or retrofitting diesel engines.

The recently-passed federal stimulus bill included $300 million for “Clean Diesel ”projects, mainly in the form of grants to diesel fleet owners to pay part of the cost of retrofitting engines. Locally, the Port of Vancouver will get $357,500 to retrofit engines on trucks, loaders, and forklifts. And TriMet will get $400,000 to retrofit engines on 29 buses.

“I think there’s an opportunity for unions to work with us to develop the partnership relationships we need with these fleets to raise the priority,” Downing said.

In some areas, the International Longshore and Warehouse Union has made an issue of diesel exhaust, working in coalition with community groups to get ships, trains and trucks to turn off their engines when not in use.

There’s not much that individual workers can do to reduce risk. Ordinary dust masks don’t stop the fine particles that are the problem. The one exception is when workers turn engines off that are not in use. Downing said it’s a myth that diesel engines need to be kept running all the time.

Anti-idling campaigns aim to make turning engines off a worker habit — and workplace policy. They’ve had particular success at school districts. The Oregon Department of Education encourages all school districts to have no-idling policies for school buses — especially when they’re lined up outside schools. And a bill in the Oregon House of Representatives would carry the ball further. House Bill 2186 would authorize the DEQ to write rules restricting engine use by parked medium-duty and heavy-duty trucks and by commercial ships while at port, and require truck stops and ports to make electric power available as an alternative to engine use.

“When I first started doing this,” Downing said, “I really had to scramble. People were very skeptical. Everybody was interested in being second, but very few were interested in being first.”

© Oregon Labor Press Publishing Co. Inc.