DEQ finds several ‘deficiencies’ Colonial Pipeline needs to fix at Huntersville gasoline spill site

HUNTERSVILLE, N.C. — Following a review, the North Carolina Department of Environmental Quality (DEQ) has found “several deficiencies in the Comprehensive Site Assessment (CSA) submitted by Colonial Pipeline on Jan. 20.”

The department has issued a Notice of Continuing Violation detailing what needs to be done to fix the issues. It has also directed Colonial to extend the radius of residential private well sampling.

“We will continue to hold Colonial Pipeline accountable for its actions and response to the largest gasoline spill in North Carolina’s history,” said Division of Waste Management Director Michael Scott. “The Comprehensive Site Assessment lacks critical information necessary to determine the full extent of the impacts of this event. This information is crucial for the protection of public health and the environment.”

Due to the size and scope of the gasoline spill, estimated at 1.2 million gallons, DEQ also has directed Colonial Pipeline to extend residential private well sampling 500 feet beyond the edge of the current sampling radius. The six additional wells in the expanded sampling radius, many of which were tested in the initial response, will be sampled once every six months going forward.

To date, Colonial has reported no gasoline products in drinking water well samples within the sampling radius.

The Notice of Continuing Violation identified 22 corrective actions needed to “remedy the CSA deficiencies.” By April 26, Colonial must:

  • Install at least 12 deep wells to fully define the vertical extent of the contamination.
  • Supply free product volume estimate documentation.
  • Provide additional subsurface cross-sections to further develop the conceptual site model.
  • Describe the waste profile of excavated soil and permanent disposal location.
  • Provide a report that identifies the potential for vapor intrusion in residences, buildings and utility conduits.
  • Provide a detailed summary about air and noise monitoring sampling efforts.
  • Provide additional information about nearby surface water features, particularly neighboring springs.

In November, DEQ required Colonial Pipeline to recalculate the estimated release because “the amount and continued rate of free product recovery, along with other data submitted by Colonial Pipeline, indicated that the spill is significantly larger than initially reported. As of Feb. 23, 740,368 gallons of free product and 592,037 gallons of petroleum contact water have been recovered and transported off-site for disposal.”

In a release, DEQ said it “required Colonial Pipeline to submit a CSA as part of its regulatory process to ensure the site is restored to the state’s groundwater standards. It identifies and describes the groundwater plume and soil impacts, and it is the next step in ongoing cleanup and remediation efforts. The CSA, and any additional information requested by DEQ, will dictate the direction of the Corrective Action Plan. DEQ must approve the CSA before Colonial Pipeline can prepare and submit its Corrective Action Plan, which will detail Colonial’s remedial actions.”

Colonial has installed pumps in the wells within the free product area and is still recovering about 3,000 to 5,000 gallons of gasoline each day.

Colonial issued the following statement Thursday:

“From the beginning of this incident, Colonial Pipeline Company has cooperated and coordinated with state and federal regulators as well as Mecklenburg County officials, with regular on-site meetings and updates. We continue to provide detailed information as required and as requested regarding ongoing recovery and remediation efforts, including proactive and voluntary activities at the site and on our pipelines. We are reviewing NCDEQ’s most recent request, which includes activities that are already underway, and some information requests that have already been previously submitted, and we will work diligently to respond to the department’s additional requests.”