Process Safety Management Investigations

Investigation

Incident Description

West Fertilizer Explosion and Fire

Incident Description: On April 17, 2013, a massive explosion at a fertilizer storage and distribution facility fatally injured twelve volunteer firefighters, two members of the public and caused hundreds of injuries. As a result, a recommendation was issued to add fertilizer grade ammonium nitrate to the PSM Standard list of highly hazardous chemicals.

Chevron Refinery Fire

Incident Description:On August 6, 2012, the Chevron U.S.A. Inc. Refinery in Richmond, California, experienced a catastrophic pipe failure in the #4 Crude Unit. The incident occurred from the piping referred to as the “4-sidecut” stream, which was a carbon steel pipe with low silicon concentrations. The pipe ruptured, releasing flammable, hydrocarbon process fluid which partially vaporized into a large vapor cloud. Testing determined that the pipe failed due to thinning caused by sulfidation corrosion, a common damage mechanism in refineries.  Inspection of sufidation corrosion for carbon steel components containing low silicon concentrations is challenging. Several recommendations were issued to various government entities in California resulting in the development of stronger PSM regulations in the state of California.

Tesoro Refinery Fatal Explosion and Fire

Incident Description:An explosion and fire led to the fatal injury of seven employees when a nearly forty-year-old heat exchanger catastrophically failed during a maintenance operation at the Tesoro refinery in Anacortes, Washington. 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. Tesoro, like others in the industry, used published data from the American Petroleum Institute (API), called the Nelson Curves, to predict the susceptibility of the heat exchangers to HTHA damage.  The CSB found these curves unreliable because they use historical experience data concerning HTHA that may not sufficiently reflect actual operating conditions.  Additionally, several recommendations were issued to various government entities in Washington for the development of stronger PSM-related state regulations.

Motiva Enterprises Sulfuric Acid Tank Explosion

Incident Description:On July 17, 2001, an explosion occurred at the Motiva Enterprises refinery in Delaware City, Delaware. A work crew had been repairing a catwalk above a sulfuric acid storage tank farm when a spark from their hot work ignited flammable vapors in one of the tanks. This tank had holes in its roof and shell due to corrosion. The tank collapsed, and one of the contract workers was killed; eight others were injured. The refinery's sulfuric acid tanks had a history of leaks but Motiva took no effective action, even when its own tank inspectors recommended full internal inspections "as soon as possible" in three successive annual reports prior to the explosion. Three weeks before the explosion, an operator submitted a formal Unsafe Condition Report noting holes in two tanks and pointing out that the hose used to blanket the tank with nonflammable carbon dioxide was improperly installed. The CSB found Motiva investigated the Unsafe Condition Report but took no action to correct the deficiencies. A recommendation was issued to include atmospheric storage tanks interconnected to a PSM covered process in the PSM Standard.

BP America Refinery Explosion

Incident Description:At approximately 1:20 p.m. on March 23, 2005, a series of explosions occurred at the BP Texas City refinery during the restarting of a hydrocarbon isomerization unit. Fifteen workers were killed and 180 others were injured. The explosions occurred when a distillation tower flooded with hydrocarbons and was overpressurized, causing a geyser-like release from the vent stack.  The investigative team found a number of problems with the facility's preventative maintenance program that were causally related to the March 23 accident. The CSB concluded that BP supervisory personnel were aware of the equipment problems with the level transmitter before the March 23 startup but still had signed off on equipment checks as if they had been done, which the report said reflected the prevalence of production pressures at the refinery.  The day of the incident, a blowdown drum vented highly flammable material directly to the atmosphere. The drum was never connected to a flare since its construction in the 1950s. The previous owner of the refinery, Amoco Corporation, replaced the ISOM unit blowdown drum in 1997 with identical equipment; Amoco refinery safety standards recommended connecting the drum to a flare when such major modifications were undertaken, but this was not done. A recommendation was issued to strengthen the planned comprehensive enforcement of the PSM Standard and to require a management of change review be conducted for organizational changes..

Improving Reactive Hazard Management

Incident Description:In August 2000, following its investigation of a serious reactive incident at Morton International, the Board initiated a comprehensive review of reactive hazards nationwide. The purpose of the investigation was to develop recommendations to reduce the number and severity of such incidents. One of the recommendations was to amend the PSM Standard to achieve more comprehensive control of reactive hazards that could have catastrophic consequences.