How dangerous is coal ash? Well, that depends

How dangerous is coal ash? Well, that depends

Source:, June 8, 2014

If coal ash were a person, it would need a really good psychiatrist to treat a classic case of schizophrenia.

Is this power-plant byproduct the “toxic sludge” so threatening to the state’s ground water, streams and lakes?

Or is it the potentially beneficial substance Charlotte coal ash expert John Daniels works with in a quest to recycle more of it in roads, buildings and other uses?

“It’s important to remember that 99 percent of this material is just like soil,” said Daniels, an associate professor of civil engineering at UNC-Charlotte. “It’s that 1 percent that gives it the bad name, but really you can have regular dirt that is just as bad.”

Daniels cautions that he does not absolve coal ash of the Hyde part of its Dr. Jekyll and Mr. Hyde composition.

The stuff is, indeed, potentially harmful in the massive quantities it has been stored up by Duke Energy and other power companies around the nation.

“The difference between a poison and a remedy is the dose,” said Daniels, who is among a team of coal ash researchers at UNC-Charlotte. “Let’s keep the actual risk in perspective.”

As a waste, he said, coal ash ranks “somewhere between dirt and (household) garbage, and it’s closer to dirt.” Like garbage, the ash contains materials that could harm the environment so it needs to go in lined landfills if it can’t be recycled, said Daniels who has done consultant work for Duke Energy during his career.

But as a threat, coal ash pales beside inherently dangerous, industrial chemicals like the compounds you might find in some dry-cleaning fluids or gas pumps, he said, And there’s a potential to recycle much greater amounts in years to come, he believes.

A liter of the Dan

Coal ash spurted to regional prominence this winter when, after years of neglect, a drainage pipe ruptured beneath a Duke Energy ash-storage pond beside the Dan River, on the outskirts of Eden.

The ensuing spill unleashed as much as 39,000 tons — 78 million pounds — of coal ash into the river from the utility’s retired Dan River Steam Station.

The public learned to fear an industrial material few gave much thought to before that. Environmentalists doubled down on coal ash-related lawsuits against the Charlotte-based utility, which has a total of 33 ash ponds statewide storing huge quantities of the material from decades of power production by a total of 14 active and decommissioned, coal-fired plants.

The utility already recycles some of the ash produced by the active plants, sends some to landfills and has promised to close all the ponds, but in a manner environmentalists and some lawmakers criticize as too indefinite and slow.

The 1 percent of coal ash with a potential to harm involves such metals as arsenic that humans ingest routinely in small doses every day, Daniels said.

“You could have drank a liter of Dan River water on the day after the spill and close to the spill, and you would have consumed less arsenic than you usually ingest from other natural sources” daily, he said.

Solution to pollution

Belews Lake — in Stokes County northwest of Greensboro — became the site of a classic coal ash contamination incident after selenium-laced, ash discharges from Duke Energy’s plant there killed off many of the fish in the 1970s.

But the lake was too small, with too little fresh water flowing into it from a feeder creek, to adequately dilute the selenium in wastewater, Daniels said.

By contrast, Dan River’s “flow rate” dwarfs that of the lake, with daily infusions from that same Belews tributary upstream and from many others, he said.

That’s why Daniels believes the Dan River likely will escape the Feb. 2 spill with few lasting scars: “Dillution is not the solution to pollution, but it sure helps.”

Environmental groups see it as beside the point whether the relative toxicity of coal ash matches up favorably with that of benzene or some other industrial chemical.

North Carolina must reckon with volumes of coal ash that make it a serious threat, they say, a fact recognized in Duke Energy’s recent agreement with the U.S. Environmental Protection Agency to clean up the Dan spill.

Superfund invoked

That agreement was forged “under the Superfund statutes, which underscores the danger of coal ash,” said Frank Holleman, senior lawyer with the Southern Environmental Law Center in Chapel Hill.

“The Superfund statutes are not used to address the cleanup of mere dirt or sand; they are used to address dangerous substances,” Holleman said. “Coal ash is certainly not ‘dirt,’ as the people who live along the Dan River and live in the real world can tell any professor who might think otherwise.”

In fact, the Duke-EPA agreement asserts that coal ash contains a number of toxic substances “such as arsenic and a whole range of heavy metals,” Holleman said. “The storage of coal ash in unlined pits has resulted in these toxic and hazardous substances being transmitted into ground water, rivers and drinking water supplies.”

Daniels’ research with coal ash at UNC-Charlotte involves making the substance more water resistant, so that it can’t be transported into surface or ground water.

He is one of several professors and others at UNC-Charlotte who work on coal ash research in Duke Energy’s hometown.

Other research under way at the school includes developing a “geopolymer” concrete mixture in which ash displaces traditional cement. Daniels and his colleagues also are exploring ways of combing ash with power-plant wastewater and other additives to make a stable, construction material that would pose no pollution threat.

A bill pending before the General Assembly this session earmarks $5 million for the Charlotte school and N.C. State University to fund further research into coal ash recycling and other energy-related issues.

Search for options

In recent years, the power industry successfully recycled some types of coal ash for use in concrete and other building supplies, a practice some environmentalists are beginning to question now for fear problem metals could “leach out.”

Meanwhile, EPA remains conflicted about formally classifying coal ash “hazardous” as a nationwide policy. Agency directives in 1993 and 2000 found such across-the-board action “not warranted” by scientific fact. The agency’s official website touts the construction products in which it’s recycled, from grout to asphalt.

But EPA administrators began re-examining the “hazardous” issue after the massive, coal ash spill near Kingston, Tenn., in December 2008, the largest in U.S. history. They are obligated by court order to finish their inquiry and release its results later this year.

Daniels said he would be shocked if the EPA rescinds its earlier rulings and reclassifies coal ash as a hazardous substance.

If such a decision leads to restrictions against recycling and requires coal ash to be buried in specialized landfills — millions of tons in North Carolina alone — it would be a huge mistake, he said.

The state would end up maxing-out its landfill space on a material that is not that dangerous, leaving less space and fewer financial resources to deal with other chemical waste that truly merits that level of disposal, Daniels believes.

Duke Energy’s unlined ponds need to be shut down because it’s not wise to store anything that way with a potential to pollute, he said.

That means some likely will end up buried in a landfill.

“But landfill only what absolutely must be land-filled,” Daniels said. “Let’s try to reuse it. Let’s recycle as much of it as we can.”

That’s an area about which he and the environmental law center agree.

“EPA and other experts indicate that recycling of coal ash in concrete and wallboard has the effect of encapsulating the harmful materials and preventing them from leaching,” Holleman said. “We have not opposed this kind of recycling of coal ash to get it out of these unlined, aging, and failing pits and away from rivers.”

The important thing, Daniels said, is to strike the right balance.

“Those ponds do need to be addressed, but let’s keep it in perspective,” he said. “We have time to get the science and the engineering right.”


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