According to the company, the fire occurred at the naphtha unit 12:30 a.m. PDT during routine maintenance work. Tesoro's Emergency Incident Command responded to the incident and the affected units were shut down and stabilized.
Three workers – Daniel Aldridge, Matt Bowen and Darrin Hoines – died at the scene. Kathryn Powell and Donna Van Dreumel died later on April 2 from their injuries.
Injured Tesoro employees Matt Gumbel and Lew Janz remain in critical condition at Harborview Medical Center in Seattle.
“This is a very sad time for our organization. Everyone in the Tesoro family appreciates the impact that this will have on the families involved, and we are responding quickly to ensure the safety for our employees, contractors and the neighboring community,” said Bruce Smith, Tesoro’s chairman, president and CEO.
The company is providing grief counseling and support for affected coworkers and their families and is establishing a memorial fund.
A four-member investigative team from the U.S. Chemical Safety Board (CSB) has been deployed to the scene of the explosion. CSB Investigations Supervisor Robert Hall, PE, will lead the investigation, with CSB board member William B. Wark accompanying the team.
CSB currently is investigating an October 2009 flash fire at a Tesoro refinery in Salt Lake City that occurred when flammable liquid overfilled a flare stack and ignited.
“The CSB has 18 ongoing investigations. Of those, seven of these accidents occurred at refineries across the country,” said CSB Chairman and CEO John Bresland. “This is a significant and disturbing trend that the refining industry needs to address immediately.”
Bresland said the large-scale deployment to Washington state will further complicate efforts to complete other important cases, including CSB’s investigations of the Caribbean Petroleum fuel terminal fire near San Juan, Puerto Rico; the CITGO refinery hydrogen fluoride release and fire in Corpus Christi, Texas; the Goodyear heat exchanger rupture and ammonia release in Houston; and the Exxon Mobil refinery hydrogen fluoride release in Joliet, Ill.
Tesoro Corp. is an independent refiner and marketer of petroleum products. Tesoro, through its subsidiaries, operates seven refineries in the western United States with a combined capacity of approximately 665,000 barrels per day. The company has indicated that it will cooperate fully with investigations.