Mix-Up Led to BP Explosion

A piping mix-up during reassembly following routine maintenance was the cause of a $30 million explosion last year at the BP refinery in Texas City, Texas, concludes the U.S. Chemical Safety & Hazard Investigation Board in a safety bulletin released on Oct. 15.

The bulletin was based on an accident that occurred on July 28, 2005. The board found that a carbon-steel, 8-inch-diameter elbow had inadvertently been installed in a high-pressure, high-temperature hydrogen line during a repair. In all, three similarly appearing elbows had been removed during maintenance. Three months after the repair was completed, the carbon-steel elbow blew, and the released hydrogen ignited in a fireball that burned for two hours.

The maintenance contractor had accidentally installed the carbon-steel elbow instead of one made from a more resistant alloy steel during scheduled maintenance at the plant's "resid hydrotreater unit," the board says. The board notes that contractor JV Industrial Cos. conducted the repairs and adds that BP had not informed the contractor that the pipe elbows were not interchangeable.

Among recommendations in its safety bulletin, the board urges that pipe elbows be examined with X-ray fluorescence testing devices to ensure they are made from materials tough enough for the application.

The July accident resulted in no fatalities and one minor injury. However, it occurred only four months after a fire and explosion killed 15 workers and injured 180 at the same refinery, which is the U.S.'s third largest. Consequently, the board urges BP to examine the "safety culture" at all its North American refineries.

A BP spokesman says the company concurs with the board?s recommendations and has taken a range of actions to improve safety at the plant.

The larger accident remains under review by the board, which has issued some preliminary reports and safety bulletins concerning the BP accidents (www.csb.gov). BP has committed to spending $1 billion over the next five years at the facility for improvements and has acknowledged that serious management lapses were responsible for the explosion (C&EN, Dec. 19, 2005, page 12).