RALEIGH, N.C. (AP) — A year after the sudden collapse of an old drainage pipe triggered the third largest coal ash spill in U.S. history, regulators say they are still working to determine how much to fine the nation's largest electricity company.
It took nearly a week to plug the leak from Duke Energy's Eden coal ash dump that began Feb. 2, 2014 and coated 70 miles of the Dan River in gray sludge. North Carolina environmental officials quickly issued Duke a pair of formal notices outlining violations of wastewater and stormwater regulations. The company was issued additional notices for violations after regulators found issues at other Duke coal ash dumps across the state.
A key issue in assessing what Duke (NYSE: DUK) will eventually pay depends on what, if any, long-range damage was done by the estimated 39,000 tons of ash spilled into the river. Coal ash, the waste from coal burned to generate electricity, contains toxic arsenic, selenium, chromium and mercury.
So far, officials at both Duke and North Carolina's environmental enforcement agency say recent surveys of aquatic animals show the river is recovering.
"I am glad to say that the river is thriving, and there's hard science that tells us so," Paul Newton, Duke Energy's president for North Carolina operations, said Tuesday.
Tests on water samples collected downstream of the spill immediately after the spill showed high readings for arsenic, lead and aluminum. Those levels dropped within days, however, after the ash settled to the river bottom in drifts as thick as five feet.
Under the supervision of the U.S. Environmental Protection Agency, contractors hired by Duke vacuumed out the largest pockets, recovering less than 8 percent of the ash before stopping in July.
In October, staff from the N.C. Division of Water Resources sampled aquatic insects and other tiny animals in the river, determining that the size and diversity of the populations both upstream and downstream from the spill were similar. A second study, by an environmental consulting firm hired by Duke, said in November that the river's mussels were flourishing.
But scientists and environmentalists warn it could take years to know the true long-range impact on the river. The Dan is home to two federally listed endangered species, the Roanoke logperch fish and the James spinymussel.
Dennis Lemly, a U.S. Forest Service fish biologist and professor at Wake Forest University, said past research has shown the tiny aquatic insects counted as part of the state's study can survive in polluted water and sediment. The real concern, he said, is whether they will absorb the toxic metals from the coal ash, which over time would become concentrated in the fishes and birds that eat them.
Several studies are either planned or already under way to measure whether contaminates contained in the coal ash are making their way up the river's food chain.
Records show past fines levied after large coal ash spills in other states ran into the millions.
In the worst U.S. spill, an earthen dam at a Tennessee Valley Authority ash dump in Kingston, Tenn., collapsed in 2008, sending an estimated 5.4 million cubic yards of coal ash over 300 acres, destroying 40 homes and devastating the Emory River.
The cleanup cost nearly $1.2 billion so far, and Tennessee regulators also fined the TVA $11.5 million for violating the state's water quality and waste disposal laws. The EPA did not issue any fines.
In the second worst spill, 850,000 cubic yards of ash spilled across 10 acres and into the Delaware River from a PPL power plant in Pennsylvania in 2005. The company spent $37 million for cleanup and was fined $1.5 million by the state. The EPA did not fine the company.
In North Carolina, state environmental regulators agreed to move jointly with federal authorities to issue any fines resulting from Clean Water Act violations.
After the Dan River spill, Duke signed agreements with the EPA and North Carolina to pay any costs associated with the emergency response and the costs of the agencies overseeing cleanup and environmental monitoring efforts.
EPA spokeswoman Davina Marraccini estimated Duke's costs at about $15 million. She declined to discuss potential fines, saying the investigation continued.
Drew Elliot, spokesman for the N.C. Department of Environment and Natural Resources, also declined to provide a timetable for a decision. He said Duke faced multiple violations involving both the spill and ongoing groundwater contamination from ash dumps at 13 other sites.
"As you can imagine, the information gathering, data analysis, and all sorts of other background work that goes into issuing fines is significantly expanded when an agency chooses ... to go after 14 sites instead of just one," Elliot said.
There is also a federal criminal investigation into the spill and the state's prior regulation of Duke's coal ash dumps, with at least two dozen grand jury subpoenas issued last year seeking documents from the company and its North Carolina regulators.
Environmental groups worry that the possible penalities won't be enough to prevent future pollution by Duke, a corporate giant valued at more than $50 billion.
"EPA should fine Duke for violating federal law and require that Duke address any long-term impacts from its spill in the Dan River," said Lisa Evans, senior administrative counsel for Earthjustice. "Anything else is a slap on the wrist and an insult to local communities."