State officials said two dams at a Duke Energy power plant pose a “high hazard” of killing downstream residents if they were to breach and spill, as regulators begin a systematic safety review of 49 coal ash lagoons and cooling ponds across North Carolina.
One of the two dams at the W.H. Weatherspoon Power Plant near Lumberton had previously been classified as posing an intermediate risk, requiring a safety inspection once every five years, while the other dam was exempt from safety inspections. One pond contains coal ash; the other stores water in a cooling pond.
A high hazard rating by the state Department of Environment and Natural Resources calls for increasing annual inspections for structural integrity to once a year.
“If the coal ash storage pond were to fail, material from the coal ash storage area would likely flow southeast and could impact four occupied homes located closely together on the east side of both the coal ash storage pond and the cooling pond,” said DENR spokesman Jamie Kritzer. “All four homes are within a mile of the coal ash storage pond.”
The hazard rating does not reflect on the condition of the dam but the potential risk to lives and property if the dam were to burst.
However, a high hazard rating is significant because it will be a factor used to determine how coal ash ponds are prioritized for closure by the newly created N.C. Coal Ash Management Commission under legislation awaiting Gov. Pat McCrory’s signature.
By reclassifying Weatherspoon as a high hazard this week, DENR officials are signaling the ash pits should be reviewed for early closure, and the ash may have to be removed to a safer location. Charlotte-based Duke had previously opted for the most economical option: leaving the ash at the site in place and covering it with a layer of soil.
The two Weatherspoon dams are the first to be reevaluated for safety by the N.C. Department of Environment and Natural Resources, a review prompted by the February coal ash spill of 39,000 tons of slurry and sludge into the Dan River.
Most of North Carolina’s 33 coal ash pits already have a high hazard ranking. Kritzer, the DENR spokesman, said some could be reclassified to a lower hazard rating.
A coal ash dam that is exempt from inspections is either under 25 feet high or contains less than 50 acre-feet in volume. North Carolina dams have been assigned hazard ratings since 1967.
The Weatherspoon coal ash storage site was the first in the state set to be decommissioned after the coal-burning power plant there was mothballed in 2011 and demolished two years later. Duke inherited the facility when it acquired Raleigh-based Progress Energy in 2012.
Duke planned to submit a closure plan earlier this year but suspended the application after DENR filed lawsuits alleging the facilities are causing groundwater contamination across the state.
The Weatherspoon site contains 1.7 million tons of ash, one of the smaller ash pits in Duke’s system.
DENR’s hazard rating is based on an emergency action plan Duke submitted in response to a March request for such a plan after the Dan River spill.
The emergency plan is considered confidential and for security reasons is not available for public review, said Duke spokesman Jeff Brooks.