On Sunday, May 23, 2004 at approximately 8 a.m., Olympic Pipeline experienced a shut down of its pipeline due to a leak and resulting fire at its Renton facility. The source of the fire was a fuel leak from a 3/8" stainless steel tube used for sampling pipeline liquid from the 16-inch main line.


Photo by Al Jones, UTC Pipeline Safety Division inspector

The Root Cause Incident Investigation Report conducted by Olympic Pipe Line Company, and completed in Sept. 2004, found that intense heat burned a small hole in the steel tube carrying fuel. The same heat source that melted the tube also ignited the fuel creating the fire. The leak occurred in a portion of the sample tube located approximately one foot above ground and running between the building's outside wall and an electrical junction box. The junction box provided above ground access to a below-ground electrical conduit.

Olympic Pipeline Company retained Anvil Corporation of Bellingham to conduct field surveys and metallurgical testing of the sample tube. Using evidence collected from Scanning Electron Microscopy testing and historical information, the company determined that the leak was caused by a concentrated heat source that burned through the sample line and ignited the fire.

Anvil determined that the type of concentrated heat necessary to create the indentations and marks on the sample tube and the back of the junction box was an electrical arc leaping the short distance between the junction box and the tube. The Olympic Root Cause Investigation team believes this electrical arc was likely the result of a ground fault that occurred within or very near, the nearby electrical substation that supplies power to Olympic's Renton Station.

Puget Sound Energy confirmed that it experienced a phase-to-ground fault of its transmission line in the general vicinity of the Olympic Pipeline facility during that time. However, PSE denies that its phase-to-ground fault was the cause of the subsequent Olympic Pipeline fire.

As a result of the investigation, BP as the Operator of Olympic Pipe Line, on its own accord, decided to do the following:

1) Ensure a minimum two-inch separation from cathodically-protected systems to prevent the type of electrical arc that occur between the sample tube and the electrical conduit.
2) Review and consider improvements to its leak detection and alarm systems at the Renton facility as well as at other Olympic facilities.
3) Determine mitigation methods to minimize and/or eliminate interaction of the facility’s ground grid and cathodic protections with future utility substation ground faults.
4) Improve communications and relationships with area emergency responders through training and discussion.