Now Playing:


Energy | Environment

Coal Dust's Environmental Impacts

Coal Logo FINAL_a
This is the second in a two-part series.

Paul Barber isn’t one to let a little rain get in the way of doing his job.

As the plant superintendent for one of the largest open-pit mines in the world, part of Barber’s job is to see that more than 100 million tons of coal get loaded onto trains every year and sent from the Black Thunder Mine in northeastern Wyoming to power plants around the country.

Barber sits in front of a wall of computer monitors with blinking multi-colored lights. Asked what happens if it rains on an uncovered coal train, his answer isn’t nearly as high-tech as his surroundings.

“They have weep holes in ‘em so water don’t necessarily pool in the car grooves,” he says, going on to explain that the holes allow water to drain out of the moving cars.

Adding water weight to a coal train isn’t good for business, but allowing that water to filter through the coal car, taking dust with it, may not be a good thing for the environment.

Powder River Basin coal mines already have to deliver coal by train to destinations in the rain-soaked Pacific Northwest. Some of that coal is hauled by train to export terminals in British Columbia. There it’s loaded onto ships bound for Asia. And lots more of that coal could be headed to Oregon and Washington, where five coal export terminals are under consideration.

With the prospect of increased coal train and barge traffic through the Northwest, some are raising concerns about how escaped coal dust could affect the environment — on the land and under water.

Paul Barber is the superintendent of Black Thunder Mine, one of the largest open pit mines in the world. Credit: Katie Campbell

The Environmental Protection Agency says that if rain falls on piles of coal it can flush out heavy metals like arsenic and lead. Elevated levels of arsenic have been found in the soil surrounding a large coal export terminal in Virginia.

The EPA commissioned a report in the late 1970s to assess the impacts of transporting coal. EarthFix contacted the EPA to see if there was any more current research available about the environmental effects of transporting coal. The EPA said they did not have any more current information.

Here are some excerpts from the 1978 report:

  • “Operation of a rail line to transport coal can cause pollutant emissions, noise, potential for fires, leaching of chemicals and detrimental aesthetic effects.”
  • “Coal dust will cover the leaves of nearby vegetation and reduce its photosynthesis capabilities.”
  • Coal dust could have “toxic effects on wildlife that might browse on this vegetation.”

But the effects of coal dust may not be limited to the land. Coal trains will also follow the Columbia River, where some of the coal could be loaded onto barges. If the Gateway Pacific Terminal is built near Bellingham, up to 9 trains per day could make the journey north and south along Puget Sound.

A coal train travels along Puget Sound. Credit: Katie Campbell

“The fact that mussels and oysters filter feed means that small particles of coal will be taken up by these organisms,” says Gary Shigenaka, a marine biologist with the National Oceanic and Atmospheric Administration. Shigenaka has over 20 years of experience working emergency response on events like the Exxon Valdez oil spill in Alaska and Deepwater Horizon in the Gulf.

I asked him what happens to marine animals if they ingest coal dust. The answer? Scientists aren’t sure. “We call that the ‘so what question,’” Shigenaka says. “And that’s the really hard question to answer. You’re exposing an organism to contaminant A, contaminant B. So what? Why should we care about it?”

There are some who say maybe we shouldn’t care about coal dust. After all, coal occurs naturally. In Alaska there are places along the coast where waves crash directly onto exposed seams of black coal.

Coal beach in Alaska
Natural coal seams meet the Chukchi Sea near Wainwright, AK. Credit: Mandy Lindeberg/NOAA

“Coal dust shouldn’t have an adverse effect on the marine environment,” says Peter Chapman. He’s a scientist with Golder Associates, an environmental consulting firm which has conducted research for the fossil fuel industry.

And sure, coal has heavy metals in it, but Chapman says it’s a rock like any other. It’s crystalline structure locks in the arsenic, mercury and other metals.

That means shellfish and other animals that ingest coal dust can’t get at the harmful substances inside, he says. “Unless you have some very strong acids or ways of changing the matrix they will be held in there and they won’t be what we call ‘biologically available.’”

But some disagree with Chapman’s claims and say more research needs to be done - particularly on the chronic, low-level input of coal dust to the environment that steady coal train traffic could bring.

Here’s a blurb from one study by scientists in New Zealand:

“There are surprisingly few studies in the marine environment focusing on toxic effects of contaminants of coal at the organism, population or assemblage levels, but the limited evidence indicating bioavailability under certain circumstances suggests that more detailed studies would be justified.”

One thing to consider here in the Northwest: the coal that would come from Powder River Basin mines is softer than the coal mined back east in places like West Virginia. That means it breaks down into dust more easily, making it more readily available to animals –- especially the filter feeders at the bottom of the food chain.

Furthermore, heavy metals may not be the most concerning contaminants in coal dust, says John Incardona, a biologist and toxicologist in Seattle with NOAA. Incardona’s research focuses on what are called polycyclic aromatic hydrocarbons or PAHs. You’ll find these compounds in fossil fuels, including coal. And they’re a problem for fish.

“It’s a very simple matter,” Incardona explains. “If it leaves the PAH source and goes into the water and gets taken up by the fish it will be toxic. It doesn’t matter if it’s coming from coal dust or fuel.”

PAHs have been connected with liver disease and lower reproductive rates in English sole in Puget Sound. Incardona’s research has shown that when salmon and zebrafish embryos are exposed to PAHs in the lab, their hearts don’t develop normally. That can affect their growth as well as their ability to survive and reproduce.

Scientists don’t know exactly how much heavy metals and PAHs escape from coal –- especially when it’s in dust form as opposed to solid chunks, but Incardona says it wouldn’t be too hard to find out.

“There is a lot of simple science that can be done to answer these basic questions,” Incardona says. “But even with oil, almost all things relating with fossil fuel, seems like nobody really wants to get those answers.”

Trains have been carrying coal around the country for decades. But there is little research that looks specifically at the environmental impacts of chronic exposure to coal dust.

So far the EPA, the Washington Department of Ecology and the Oregon Department of Environmental Quality have raised concerns about coal dust.

Some say coal dust isn’t as much of a concern as the larger environmental impacts of coal exports – like global CO2 emissions, air pollution from Asia or diesel exhaust from locomotives. But as communities in the Northwest consider coal export terminals, and the significant increase in coal train traffic that those terminals will bring, some experts believe coal dust merits a closer look.

Monday: Dust From Coal Trains And What It Means For Human Health.

(Hover over markers to hear reports on coal in communities of the Northwest. Then click “website” for more EarthFix coverage. Click here for larger map view. Note: Train routes are approximations. They illustrate potential corridors based on existing lines and publicly available information.)

More News

More OPB