NTSB: Cause of Michigan Explosion Similar to San Bruno Fire

The National Transportation Safety Board on Tuesday issued its report on the 2010 pipeline explosion in Marshall, MI, and the conclusions about the disaster show glaring similarities to the San Bruno fire.

A 30-inch pipeline owned and operated by Enbridge ruptured on July 25, 2010, just months before the PG&E pipeline explosion in San Bruno, and spilled 840,000 gallons of crude oil near the Kalamazoo River in Michigan.

Investigators from the NTSB concluded that pervasive organizational failures and weak federal regulations led the pipe to rupture. Multiple cracks in the pipe fatigued by corrosion grew over time and eventually an 80-inch-long breach, and those defects were overlooked by the company and regulators, investigators said.

NTSB Chairwoman Deborah Hersman said “the operator took advantage of weak regulations” and questioned whether Enbridge and PG&E are “representative of others.”

In the PG&E explosion, the NTSB found that that expanded over time and eventually ruptured. In addition to finding PG&E at fault for the disaster, the NTSB said that state and federal regulators were at fault as well for their lack of oversight related to pipeline safety.

PG&E is now facing a trial for damages caused by the explosion and has had to spend millions of dollars repairing its pipeline system. The utility could also face millions of dollars in fines from state regulators.

Carl Weimer, the executive director of the Pipeline Safety Trust, said the report on the Enbridge explosion is another reminder that pipeline safety needs to be reexamined throughout the country. The Pipeline Safety Trust is an organization formed after the 1999 gasoline explosion in Bellingham, WA, that works to keep the pipeline industry accountable so that further accidents don't happen. 

“While the industry through regulations has been given great flexibility to determine the safety and integrity of their own pipelines it has become increasingly clear that the industry does not always handle their responsibilities responsibly, and that government regulators do not have the resources, data, or ability to verify that industry decisions are safe enough” Weimer said in a statement.

To see the report on the Enbridge accident, visit the NTSB's website.

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