Colonial Pipeline Spill

Information and updates, as they are available, related to the Colonial Pipeline Spill that occurred at the Oehler Nature Preserve owned by Mecklenburg County in the Town's extra-territorial jurisdiction off Huntersville-Concord Road on August 14, 2020.  

November 2, 2021 - NC DEQ Files Action Against Colonial Pipeline

The North Carolina Department of Environmental Quality (DEQ) today filed a Complaint and Motion for Injunctive Relief in Mecklenburg County Superior Court to force Colonial Pipeline to meet their obligations as the responsible party in the state’s largest gasoline spill. As outlined in the complaint, Colonial has failed to provide DEQ with essential information required for the appropriate remediation at the site.

October 27, 2021 - DEQ's Division of Water Resources issued a Notice of Regulatory Requirements to require Colonial to collect surface water data for pH, conductivity, dissolved oxygen, VOCs, total lead and PFAS (in specific locations)

October 19, 2021 - NC DEQ issued a Notice of Continuing Violation (NOCV) and a Notice of Regulatory Requirements (NORR) to Colonial Pipeline.  

This NOCV notes that Colonial remains in violation of the previous Notice of Violation on September 25, 2020 and other NOCV's from February 24, 2021, April 26, 2021 and May 5, 2021.

This NORR notes items such as estimation of contamination mass in the soil, air sampling analytical results, details about petroleum contact water and other details that are to be included in monthly groundwater monitoring reports that Colonial Pipeline submits to NC DEQ, in addition to information stated in previous correspondence.  

April 4, 2021 to July 27, 2021 Air Quality Monitoring Report:  Report shows results air quality monitoring during by NC DEQ and Mecklenburg Air Quality.  Report found the compound concentration averages for samples collected between April 4 and July 27, 2021 had values below the ATSDR or NIOSH guidelines for which values are available. 

August 2021 Monthly Monitoring Report (Colonial Pipeline to NCDEQ)

July 2021 Monthly Monitoring Report (Colonial Pipeline to NCDEQ)

June 2021 Monthly Monitoring Report (Colonial Pipeline to NCDEQ)

May 2021 Monthly Monitoring Report (Colonial Pipeline to NCDEQ) 

May 5, 2021 - NC DEQ issued a Notice of Continuing Violation about items not included in the revised Comprehensive Site Assessment and reevaluation of the estimated volume of gasoline released

April 2021 Monthly Monitoring Report (Colonial Pipeline to NCDEQ)

April 26, 2021 - Colonial Pipeline Revised CSA Submitted to NC DEQ

April 17, 2021 - Colonial Pipeline Supplemental 7000.1 Report to PHSMA 

April 16, 2021 - NC DEQ: Colonial Pipeline increases estimate of gasoline release near Huntersville.  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.

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 was 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.

March 2021 Monthly Monitoring Report sent to NC DEQ by Colonial Pipeline

On March 29, 2021, The Pipeline and Hazardous Materials Safety Administration (PHMSA) issued a Notice of Proposed Safety Order  to Colonial Pipeline. "The Notice proposes that Colonial Pipeline Company take certain measures with respect to the Colonial Pipeline System to ensure pipeline safety." The Notice proposes 13 actions that Colonial Pipeline will have 30 days to provide a written response or it waives its right to contest the Notice.

February 2021 Monthly Monitoring Report sent to NC DEQ by Colonial Pipeline.

February 25, 2021: Following review of the Comprehensive Site Assessment submitted by Colonial Pipeline last month, NC DEQ cites deficiencies in Colonial Pipeline’s Comprehensive Site Assessment; directs extension of private well sampling radius.

Due to the size and scope of the release, estimated in the CSA 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 approximately six additional wells in the expanded sampling radius, many of which were tested in the initial response activities, 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 identifies 22 corrective actions needed to remedy the CSA deficiencies. By April 26, Colonial must complete further actions, including but not limited to:

  • 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; and
  • Provide additional information about nearby surface water features, particularly neighboring springs.

January 21, 2021: DEQ reviewing Colonial Pipeline’s New Estimated Release Volume and Comprehensive Site Assessment - In this update from NC DEQ, Colonial Pipeline is now estimating the amount spilled into Oehler Nature Preserve at nearly 1.2 million gallons.  View full Comprehensive Site Assessment (CSA)

The CSA 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 details Colonial’s remedial actions.

Previous Documents:

November 30, 2020 Monthly Monitoring Report Submitted to NC DEQ by Colonial Pipeline 

November 5, 2020 DEQ Statement on Volume of Colonial Pipeline’s August Gasoline Spill in Huntersville

Colonial Pipeline submitted its Initial Abatement Action Report to NC DEQ on Oct. 30, 2020. This report indicates recovery in excess of 330,000 gallons from the spill site and recovery wells to date. It does not include a revised spill total.

September 25, 2020 Notice of Violation from NC DEQ to Colonial

September 13, 2020 Update from Colonial Pipeline - 48-hour estimate of 63,000 gallons spilled revised to 272,580 gallons of gasoline released (they estimate approximately half has been recovered) as part of their 30-day report due to the Pipeline and Hazardous Materials Safety Administration by September 14. As noted above, this number now stands at over 330,000 gallons.

Click Here to View Report submitted to PHMSA on September 13, 2020.

Charlotte-Mecklenburg Emergency Management Fact Sheet (August 26, 2020)

Handout from August 27, 2020 Community Meeting

Video Feed from August 27, 2020 Community Meeting (.mp4)

(Note: this is the virtual feed and shares what the audience saw that night.  While you can't see the audience, you can hear their questions and statements.  Feed begins just after start of meeting with introductions by regulatory agencies, starting with Tony Bateman from Charlotte-Mecklenburg EM).  

Contact information for agencies represented are included below:

Additional Resources and Contact Information from August 27 Community Meeting:


The Division of Waste Management through NC Department of Environmental Quality is the agency responsible for oversight of cleanup and remediation from this incident. 

NC DEQ has created a webpage to track this incident:  



May 5, 2021 - DEQ Issued Notice of Continuing Violation for Items not included in Comprehensive Site Assessment and reevaluation of estimated volume of gasoline leaked into ground.

April 26, 2021 - Colonial Pipeline submittal of revised CSA to NCDEQ

February 25, 2021 - DEQ Issued Notice of Continuing Violation after its review of the CSA found 22 deficiencies - for Colonial Pipeline to address by April 26.

On January 20, 2021, Colonial Pipeline submitted its Comprehensive Site Assessment to NC DEQ.

On Dec. 9, 2020, DEQ sent Colonial Pipeline a second Notice of Regulatory Requirements for additional information needed to carry out DEQ's investigation into the nature of the release.

Initial Abatement Action Report from Colonial Pipeline (Oct. 30, 2020) 

On Sept. 25, 2020, DEQ issued a Notice of Violation to Colonial Pipeline for impacts to groundwater quality.

September 25, 2020 Press Release Announcing Notice of Violation

August 20, 2020 Notice of Regulatory Requirements
MO-88795_95827_G_NORR_20200820_Notice of Regulatory Requirements (8/20/2020)