The US Chemical Safety Board has released a video that goes into the root causes of Tesoro’s Anacortes refinery fatal accident, which took place in April 2010. The disaster occurred when a nearly 40 year old heat exchanger ruptured violently during startup of the refinery’s naphta hydrotreater unit.
Watch the video below that shows what likely happened.
The following excerpt is reproduced from the CSB’s website.
The CSB’s investigation found an immediate cause of the tragedy to be long-term, undetected High Temperature Hydrogen Attack (HTHA) of the steel equipment, which led to the vessel rupture on the day of the accident. The CSB found the industry’s standard for determining vulnerability of equipment to HTHA, to be inadequate.
In the video Investigator Lauren Grim discusses HTHA, stating: “High temperature hydrogen attack, or HTHA, – is a common hazard that has long been known within the petrochemical industry. However, Tesoro engineers and corrosion experts did not believe it could occur within the heat exchanger that ultimately failed.”
The CSB’s investigation report, approved in May 2014, is one of the most extensive and complex refinery explosion investigations. The investigators also reported their findings of a substandard safety culture at Tesoro, which led to a complacent attitude toward flammable leaks and occasional fires over the years. And the CSB found that the complexity of the startup procedure typically required more than just the one outside operator. Yet operating procedures were not updated to account for the role of additional personnel during the hazardous non-routine work.
The CSB made recommendations in these areas to both the industry group, which issues guidance on HTHA, the American Petroleum Institute, as well as to Tesoro.
Investigator Dan Tillema says, “The CSB found that if Tesoro had a strong safety culture, it would have addressed the ongoing leaks and defined a reasonable number of essential personnel for the startup activity. Had Tesoro done these things, we concluded that fewer workers would have been present on the night of the accident, and lives would have been spared.”
The CSB’s final report also recommended that the governor and legislature of the State of Washington significantly strengthen the oversight of refineries. Specifically, the Board called on the state to require refineries to:
– conduct more comprehensive hazard analyses and damage mechanism reviews;
– document the effectiveness of process safeguards;
– increase the role for worker representatives in process safety management
– have company safety reviews examined by technically competent regulators
Chairperson Rafael Moure-Eraso said, “Seven lives were lost at Tesoro. It should not have happened. Companies, workers, and communities would all benefit from a more rigorous regulatory system that is focused on continuously lowering risks.”
The CSB is an independent federal agency charged with investigating industrial chemical accidents. The agency’s board members are appointed by the president and confirmed by the Senate. CSB investigations look into all aspects of chemical accidents, including physical causes such as equipment failure as well as inadequacies in regulations, industry standards, and safety management systems.