Report details errors that led to deadly Tesoro refinery explosion

ANACORTES, Wash. -- The public will finally get answers to one of the largest deadly refinery accidents in U.S. history.

In April 2010, equipment at the Tesoro plant in Anacortes exploded and caught fire, killing seven workers. Subsequent investigations have found it could have been prevented.

"They are learning that they have to run below what they thought were the set temperatures, and to do the proper testing as they go to stay ahead of the problems," said David Beninger, a Seattle attorney who represented the victims' families in a wrongful death claim.

Beninger sued Tesoro and Shell Oil Company and just settled for $39 million, which will be split among the victims' families. But Tesoro's trouble's aren't over because the U.S. Chemical Safety Board (CSB) is presenting its own findings.

"It's tough for the families because this is a process and they were interested in making sure that one, the right people are held accountable, and two, other people don't have to walk in their shoes and feel the same pain they go through," Beninger said.

The CSB report calls on Tesoro to adopt new safety protocols after finding that the refinery failed to check for cracks in a heat exchanger. The report says the explosion was caused by damage to the heat exchanger, a mechanism known as "high temperature hydrogen attack" or HTHA, which severely cracked and weakened carbon steel tubing leading to a rupture.

The draft report makes far-reaching recommendations to the federal Environmental Protection Agency and the Governor and State Legislature of the State of Washington to more rigorously protect workers and communities from potentially catastrophic chemical releases.

Using sophisticated computer models, the investigation found the industry-wide method used to predict the risk of HTHA damage to be inaccurate, with equipment failures occurring under conditions the deemed to be safe from HTHA. It cited deficiencies in the company's safety culture that led to a "complacent" attitude toward flammable leaks and occasional fires.

Investigators also determined that during the unit startup, Tesoro did not correct the history of hazardous conditions or limit the number of people involved in the hazardous non-routine startup of the heat exchangers. But because of the re-occurring leaks and the need to manually open a series of long-winded valves that required over one hundred turns by hand to fully open, a supervisor requested five additional workers to help. All seven lost their lives as a result of the blast.

Killed were: Daniel J. Aldridge, 50, of Anacortes; Matthew C. Bowen, 31, of Arlington; Darrin J. Hoines, 43, of Ferndale; Kathryn Powell, 29, of Burlington; Donna Van Dreumel, 36, of Oak Harbor; Matt Gumbel, 34, of Oak Harbor; and Lew Janz, 41, of Anacortes.

How quickly Tesoro adopts the recommendations could make all the difference in preventing a future tragedy.

"There is always the concern that if these changes...aren't adopted and implemented, meaning they have to be enforced day in and day out, then it could happen again," Beningersaid.

The report will be discussed at a public meeting at 6:30pm Thursday at Anacortes High School. People have 45 days to offer feedback.

Legal action is still pending against a company that inspected the refinery equipment prior to the explosion. Beninger said the U.S. Attorney's Office is also conducting a criminal investigation on the explosion, but a spokesperson at the agency would neither confirm nor deny that account.

On Wednesday night, a Tesoro Corp. spokesperson released a statement saying the company "deeply regrets the incident of that day."

"Our thoughts and prayers remain with the families and friends of our seven co-workers who lost their lives," the statement reads. "The Company recognizes the public receipt of the CSB's draft investigation report and acknowledges the efforts of CSB investigation teams, despite the significant and successive turnover in the agency's assigned personnel over the years. We respectfully disagree with several findings in the draft report and, most importantly, take exception to CSB's inaccurate depiction of our process safety culture. However, despite any disagreements regarding the draft report, Tesoro anticipates discussing the CSB's recommendations with the agency once the report is finalized and will consider them in light of the steps we have taken and are continuing to take to improve the safety of our facilities."