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Colonial Pipeline raises estimate of Huntersville gasoline spill

Aerial photo of the Colonial Pipeline leak site on Huntersville-Concord Road in August 2020.
Mike Harvey
Aerial view of the Colonial Pipeline gasoline spill in Huntersville in August 2020.

Colonial Pipeline has raised its estimate again for how much gasoline spilled at a Huntersville nature preserve two years ago. And the company said in a web post on Friday that the record-breaking spill probably happened weeks before it was discovered.

The spill happened when a repaired section of the underground gasoline pipeline broke in the Oehler Nature Preserve, about two miles east of downtown Huntersville.

The company now says at least two million gallons spilled, up from a previous estimate of 1.47 million gallons. When it first happened, Colonial estimated the total at about 60,000 gallons, and it has revised the number regularly as it recovers more gas daily from a network of more than 385 wells.

State regulators say it is the largest gasoline spill on land in the U.S.

Meanwhile, Colonial also said the pipeline failed on July 27, 2020. That means millions of gallons of gasoline were spilling unchecked for at least 18 days before the break was discovered on Aug. 14, 2020, by two teens riding a four-wheel utility vehicle.

"This date was validated by a third-party expert and allowed us to further analyze the operational data to estimate an updated estimated released volume," Colonial said in a post on its website Friday.

011421 Colonial gasoline spill map.jpg
Colonial Pipeline (via NCDEQ)
A revised map from Colonial Pipeline's December report to state regulators shows recovery and monitoring wells around the spill site in Huntersville. The yellow and black line is the pipeline and the yellow dotted line is the area where gasoline has been recovered.

Colonial also says it has identified repaired and other segments of the pipeline that have the same type of repair that burst in Huntersville. That's something federal pipeline regulators had requested in their own enforcement action against Colonial.

"We identified segments of our mainlines with previous repairs similar to the type at Huntersville (called a segmented Type A sleeve) and converted them all to pressure-containing Type B Sleeves.

The company now says at least two million gallons spilled, up from a previous estimate of 1.47 million gallons. State regulators say it is the largest gasoline spill on land in the U.S.

Colonial said those repairs cost $50 million. Officials also say the total cost of the Huntersville cleanup alone is now more than $55 million.

So far, Colonial said, it has recovered 1.49 million gallons of gasoline — about 75% of the new estimate — and more is being pumped from underground daily.

The company said tests show the spill has not affected drinking water wells in the area.

The pipeline is the major supplier of gasoline to markets along the East Coast. Colonial Pipeline owns 5,500 miles of pipelines along and connecting to the main route from Texas to New Jersey.

More than 600 employees and contractors have been working at the site for nearly two years. The cleanup has required removing about 8,700 tons of soil, much of it contaminated by gasoline and related organic compounds. Colonial offered no guesses about when the cleanup might be finished.

"We will be here for as long as it takes to remediate the location," Friday's statement said.

The new estimate was required by a settlement agreement that Colonial reached three weeks ago with state regulators.

Last November, the North Carolina Department of Environmental Quality (NCDEQ) sued Colonial in Mecklenburg County court seeking more data. A judge two weeks ago approved the settlement, which calls for up to $5 million in penalties, a new estimate and details of plans for the cleanup.

On Friday, NCDEQ said in a statement that it is reviewing the new estimate.

On June 30, state environmental secretary Elizabeth Biser said: “The Consent Order requires Colonial to meet its obligations to the communities impacted by the release, starting with an accurate accounting of the spill volume. This release is on track to be the largest onshore spill in our nation’s history and the order holds Colonial accountable for the necessary cleanup to restore the environment.”

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David Boraks is a veteran journalist who covers climate change for WFAE. See more at www.wfae.org/climate-news. He also has covered housing and homelessness, energy and the environment, transportation and business.