Photo of two NTSB investigators examine red repair sleeve on line 4.

​​Two NTSB investigators examine red repair sleeve on line 4.

Colonial Pipeline Company Petroleum Product Leak

What Happened

On September 21, 2015, at 12:03 p.m., an employee of Bonefish Grill in Centreville, Virginia, called the Fairfax County 911 Center to report a gasoline odor. The Fairfax County Fire and Rescue Department (FCFRD) immediately dispatched units to the restaurant in the Centre Ridge Marketplace shopping center. After arriving at the scene, firefighters confirmed everyone had left the restaurant; they established an incident command center, and they began the investigation. They did not detect the presence of flammable vapor inside Bonefish Grill and ruled out a natural gas leak; however, they noted a gasoline odor coming from the storm drains at the shopping center. Firefighters detected the presence of flammable vapor in most of the storm drains behind Bonefish Grill and Chipotle. Flammable vapor in some storm drains in front of Bonefish Grill was as high as 100 percent of the lower explosive limit (LEL); however, no liquid was visible in the storm drains.

After establishing that the gasoline did not come from the gas station that was located about 400 feet west of Bonefish Grill and that gasoline was not illegally dumped into a storm drain, firefighters considered that the odor could be coming from a leak in a nearby, buried Colonial Pipeline Company pipeline. Colonial confirmed the pipeline leak 2 days later.

What We Found

We determined that the probable cause of the release of gasoline and other refined petroleum liquids from the Colonial pipeline was a through-wall​ corrosion fatigue crack that developed at a dent in the pipeline due to residual and operational stress and exposure to the underground environment. Contributing to the accident were vague Pipeline and Hazardous Materials Safety Administration regulations that allowed the dent to remain in the pipeline. Also, contributing to the delay in recognizing the release were the limitations of pipeline Supervisory Control and Data Acquisition systems to detect small pipeline leaks.

What We Recommended

​We made recommendations to the Pipeline and Hazardous Materials Safety Administration​, the Colonial Pipeline Company​, and the Association of Oil Pipe Lines and the American Petroleum Institute​.

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