Colonial Pipeline now says it spilled 2 million gallons of gasoline in NC — 31 times greater than original estimates

This story has been updated with further response from Colonial.

Colonial Pipeline has announced it spilled 2 million gallons of gasoline in Huntersville — 31 times greater than original estimates, and now the largest onshore accident in U.S. history.

The spill happened nearly two years ago, on Aug. 14, 2020, in the Oehler Nature Preserve in Huntersville. Colonial initially estimated the amount at 63,000 gallons.

The new disclosure was a requirement of a recent consent order that requires the company to provide an updated estimate of the volume of gasoline released within 30 days. The consent order also requires the company to take specific remedial actions and pay nearly $5 million in penalties and investigative costs.

The Huntersville spill occurred when a broken “Type A sleeve” failed. That sleeve had been installed in 2004. The sleeve was supposed to protect and reinforce a shallow dent in the pipeline, but over time became weakened by corrosion.

 A leak detection system failed to alert the company of the spill, one of a series of failures over the past five years throughout the Southeast. A year ago, the Pipeline and Hazardous Materials Safety Administration (PHMSA) determined that the problems with the pipeline in Huntersville were likely present throughout Colonial’s entire 5,500-mile route.

“As part of holding ourselves accountable, we have applied lessons learned from this event across our operations,” Colonial Pipeline wrote in a prepared statement. “For example, following the event in August 2020, 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.”

However, Colonial did not make these repairs independently. They were required as part of a federal consent order with the PHMSA, which mandated that Colonial inspect its leak detection system and inventory all of its Type A sleeve repairs and determine whether they need replaced. By complying with the federal consent order, Colonial avoided being fined.

Colonial responded on July 27: “While sleeve conversions were indeed part of the consent agreement, Colonial had already initiated a framework, through our Safety Management System, to better understand the incident and apply learnings from it. Well before any regulatory enforcement action, Colonial proactively identified all similar repairs on the mainlines of our pipeline system (both stacked and segmented Type A Sleeves) and converted them all to pressure-containing Type B Sleeves. In all conversions to Type B Sleeves on the mainlines, Colonial did not observe any evidence of product having been released from the pipe.”

The consent order also requires Colonial to begin sampling groundwater by Aug. 7 for five types of PFAS — perfluorinated compounds. As part of its emergency response to the original spill, Colonial Pipeline used a fire suppressant known as F-500 encapsulate to prevent vapors from the gasoline from igniting.

At the time of the accident, “DEQ was told [by Colonial] that the encapsulate used was PFAS-free,” agency spokeswoman Laura Leonard told Policy Watch in a story published last year.

Nonetheless, DEQ asked Colonial to test for PFAS in the suppressant because agency staff were aware of the potential for contamination based on other investigations, as well as the magnitude of the spill, Leonard said. “Out of an abundance of caution, DEQ collected — and directed Colonial to collect— samples of the encapsulate.”

Colonial’s test results of the “mixed” product — fire truck water and the F-500 — showed high levels of PFOSA: 4,810 ppt. Likewise, DEQ’s sampling showed high levels of PFOSA: 5,620 ppt. The water in the fire truck contained levels of the compounds below 1 ppt. It’s possible that residue from the hose or firefighting equipment contained PFAS; a type of firefighting foam, known as AFFF, contains high levels of the compounds.