The NC Department of Environmental Quality has issued a Notice of Continuing Violation to Colonial Pipeline regarding with ongoing contamination from a major gasoline spill in Huntersville. The spill, which occurred in August 2020, released an estimated 1,289,190 gallons of product, equivalent to 30,695 barrels, the nation’s largest such spill onshore since at least 1997.
However, the figure is likely an underestimation because the extent of the contamination below ground is still unknown.
High levels of benzene, xylene, toluene and other petroleum-related chemicals have been found in monitoring wells at the site. The company says no drinking water wells have been contaminated; however, Colonial did pay to connect several households to a public water supply. It also purchased three homes near the spill site.
DEQ issued its first Notice of Violation in September 2020; this is the fourth Notice of Continuing Violation since February.
In a letter dated Oct. 19, 2021, Michael Scott, director of the Division of Waste Management, asked Colonial for updated information about the estimated volume of the spill. “As previously communicated to you by DEQ, the volume of the petroleum release is vital to understanding the magnitude of the contaminant impact,” he wrote, as well as more accurately projecting a cleanup timeline. Understanding the true extent of the contamination is also key to assessing progress on the cleanup.
Scott also asked Colonial Pipeline to provide the vertical extent of groundwater contamination — how deep it extends — through out the plume. The agency is also requiring other details, including sampling for the presence of PFAS in the “petroleum-contact water” — essentially water that has been pumped from the recovery wells along with the gasoline. The reason for that PFAS sampling is to ensure any substances used to prevent the gasoline from igniting are free of those toxic compounds.
Colonial previously told DEQ that to gather more data about the amount of gasoline spilled, it would have to shut down the pumping system that is removing the product from the groundwater. That would delay the cleanup, Colonial said. The company has also requested — and received — several extensions from DEQ in filing an adequate Comprehensive Site Assessment.
A Colonial Pipeline spokesman issued an email statement:
“Colonial Pipeline Company is reviewing NCDEQ’s correspondence and will continue to work with the department on addressing the matters identified. As we have reported to the department, Colonial has recovered approximately 30,695 barrels of product, indicating our extensive recovery and monitoring network of 301 wells is working as designed. Regular, ongoing drinking water well sampling continues to show no impacts and our priority remains focused on quickly and safely recovering product, protecting human health and safety, and restoring the surrounding environment.”
The DEQ letter noted that it could fine Colonial Pipeline, as well as take other enforcement actions. The agency could not be reached immediately for comment.