Feb 11 (Reuters) - North Carolina has asked a state judge to put a controversial settlement deal with U.S. power company Duke Energy over pollution on hold after a massive coal ash spill into a local river raised fresh concerns about water safety.
Last week Duke said a pipe broke at one of its retired coal plants, spilling 50,000 to 82,000 tons of ash, enough to fill 20 to 32 Olympic-size swimming pools, into North Carolina's Dan River.
The accident occurred amid a long-running legal battle over the storage of coal ash waste at Duke facilities. The company owns all of North Carolina's 14 coal-fired power plants, though some are in the process of being decommissioned.
North Carolina's Department of Environment and Natural Resources (DENR) filed lawsuits last year against Duke Energy alleging water quality violations at the company's plants.
It then proposed a settlement agreement with the company in July that would levy $99,000 in fines and order increased monitoring of possible contamination at the sites.
"We were already addressing coal ash ponds through our multiple lawsuits against Duke Energy and we will continue on that course once we have an updated assessment of the situation statewide," DENR Secretary John Skvarla said in a statement on Tuesday.
"This experience may cause us to reevaluate the proposed consent order," he said.
Lawyers for North Carolina sent a letter on Monday to Judge Pat Ridgeway in the Wake County Superior Court, who is handling the suits, to ask for the postponement.
Environmental groups say coal ash in the state, a byproduct of power plants containing heavy metals that can cause cancer and nervous system damage, is stored in antiquated or unlined pits and risks seeping into groundwater and nearby rivers.
The Southern Environmental Law Center, which intervened in the lawsuits, assailed the proposed settlement for failing to require a cleanup of the coal ash contamination.
DENR received almost 5,000 public comments, nearly all of them negative, on the settlement. Some changes were made to the deal after the comment period but green groups said the fines remained small and there was still no requirement for comprehensive cleanup.
Duke spokeswoman Lisa Hoffmann said that while the company was eager to complete the work outlined in the proposed settlement agreement, "the event at Dan River is a good reason to take a fresh look at our plans moving forward."
On Saturday, Duke said workers successfully plugged the pipe under the 27-acre (11-hectare) ash pond, which broke on Feb. 2.
Working with the U.S. Environmental Protection Agency and state officials, Duke is testing a coal ash removal system in a small section of the river where a lot of sediment accumulated after the release, Hoffman said.
While Duke says water quality continues to improve in the Dan River, the Waterkeeper Alliance, a water advocacy group, said its analysis had shown "extremely high levels" of arsenic, chromium, iron, lead and other toxic metals.
"The reason this happened is that Duke poorly designed these coal ash lagoons, building them on top of a storm water pipe," said Frank Holleman from the Southern Environmental Law Center. "Next to a river is no place to store this kind of dangerous substance," he said. "There is a threat every day of another catastrophic spill."
The center is also involved in two federal court cases against the company over the coal ash pollution. Duke has filed motions to dismiss both cases, which are still pending, Holleman said.
On Sunday, North Carolina's DENR admitted it had miscalculated the levels of arsenic in the river, initially reporting that sampling showed the water was safe, when it actually exceeded the standards for human health.
"We made an honest mistake while interpreting the results," said Tom Reeder, the director of water resources at DENR, in a news release. The state agency recommended that people avoid "prolonged direct contact" with the river until further notice.
DENR also said it would be creating a special task force of experts to review the state's coal ash ponds.
Concerns about coal ash storage ponds were raised long before the Dan River spill, peaking in 2008 when a dam collapse inundated a small community in Tennessee with toxic coal sludge.