The N.C. Department of Environmental Quality (DEQ) will require additional actions by Colonial Pipeline after new data shows the amount of gasoline released in Mecklenburg County’s Oehler Nature Preserve exceeds Colonial’s 1.2 million-gallon estimate. DEQ will pursue appropriate enforcement actions based on the continuing investigation and remediation activities.
As of April 15, Colonial reports 944,400 gallons of gasoline (free product) and 1.15 million gallons of petroleum-contact water have been recovered from the site since the release was discovered on Aug. 14, 2020, at a rate of approximately 3,000 to 5,000 gallons of free product per day. Colonial has reported no petroleum constituents in drinking water well samples within the sampling radius to date. However, based on recovery rates and totals, DEQ raised significant concerns about the accuracy of the estimated volume and the modeling it was based on.
“It is unacceptable that for eight months Colonial Pipeline has been unable to provide a reliable accounting of the amount of gasoline released into this community,” said DEQ Secretary Dionne Delli-Gatti. “We will take all necessary steps and exercise all available authority to hold Colonial Pipeline accountable for what has become one of the largest gasoline spills in the country.”
As the responsible party, Colonial Pipeline is required to provide an accurate estimate of the amount of product released. On April 15, Colonial verbally informed DEQ that the 1.2 million-gallon estimate was no longer accurate and that the model used was no longer appropriate. DEQ is requiring Colonial to provide: a revised estimate of total product volume released to the environment, the specific model/predictive calculation selected and reasoning for the selection, as well as all related calculations, data, assumptions, sensitivity, and calibration information and results.
Colonial is required to provide a revised Comprehensive Site Assessment (CSA) by April 26 in response to the February Notice of Continuing Violation, which identified 22 deficiencies in Colonial’s CSA and directed Colonial Pipeline to extend residential private well sampling radius an additional 500 feet.
On March 29, 2021, the federal Pipeline and Hazardous Materials Safety Administration (PHMSA) issued a Notice of Proposed Safety Order, highlighting concerns about the Type A sleeve repair at the Mecklenburg site and requiring Colonial Pipeline to take measures identifying similar repair sites and evaluating leak detection monitoring across the system. DEQ is coordinating with federal authorities on this investigation and specific impacts in North Carolina.
Since the spill was reported, DEQ has required Colonial Pipeline to take all appropriate actions to protect the community and will continue to do so throughout the cleanup process. DEQ closely monitors the progress of the site investigation and cleanup activities through onsite inspections and meetings. In addition, DEQ’s Division of Air Quality, in coordination with Mecklenburg County Air Quality, has installed air monitoring equipment onsite for sampling and analysis.
For more information, go to: https://deq.nc.gov/about/divisions/waste-management/underground-storage-tanks-section/colonial-pipeline-spill.