Texas City refinery explosion

On March 23, 2005, a hydrocarbon vapor cloud ignited and violently exploded at the isomerization process unit of the BP-owned oil refinery in Texas City, Texas. The explosion resulted in the death of 15 workers, 180 injuries and severe damage to the refinery. All the fatalities were contractors working out of temporary buildings located close to the unit to support turnaround activities. Property loss was $200 million ($322 million in 2024). When including settlements ($2.1 billion), costs of repairs, deferred production, and fines, the explosion is the world's costliest refinery accident.

The explosive vapor cloud came from raffinate liquids overflowing from the top of a blowdown stack. The source of ignition was probably a running vehicle engine. The release of liquid followed the automatic opening of a set of relief valves on a raffinate splitter column caused by overfilling.

Subsequent investigation reports by BP, the U.S. Chemical Safety Board (CSB), and an independent blue-ribbon panel led by James Baker identified numerous technical and organizational failings at the refinery and within corporate BP.

The disaster had widespread consequences on both the company and the industry as a whole. The explosion was the first in a series of accidents (which culminated in the Deepwater Horizon oil spill) that seriously tarnished BP's reputation, especially in the U.S. The refinery was eventually sold as a result, together with other North American assets. In the meantime, the industry took action both through the issuance of new or updated standards and more radical regulatory oversight of refinery activities.

The refinery was established in 1933 by Pan American Refining Corporation. Pan American merged with Standard Oil of Indiana in 1954 to form Amoco. BP acquired the refinery as part of its merger with Amoco in 1999. As of January 2005, it was the second largest oil refinery out of 23 in Texas (behind Baytown Refinery), and the fourth overall out of 142 in the United States in terms of operating capacity, which was 475,000 barrels (75,500 m³) per stream day. At the time of the accident it was one of three refineries in Texas City, the other two belonging to Marathon Petroleum and Valero Energy. The refinery was also one of five BP refineries in the U.S. and BP’s largest worldwide. It could produce around 10 million gallons (38 million L) of gasoline per day, or about 2.5% of the entire volume sold in the United States. It also produced jet fuels, diesel fuels, as well as chemical feed stocks. Its 1,200-acre (490 ha) site was covered by 29 oil refining units and four chemical units. It employed around 1,800 BP workers. At the time of the accident, about 800 contractors were onsite to support turnaround works.

At the time of the 1999 merger, the plant was losing money, but BP was extremely successful in turning the tide. In fact, the complex had performed at an all-time record profitability in 2004, with over $1 billion in profit, "more than any other refinery in the BP system" in the words of business unit leader and complex manager Don Parus. By early 2005 the refinery was making profits of around $100 million on a monthly basis.

Since 1974, there had been 23 fatalities in 20 separate accidents at the refinery. Three of these occurred in 2004, the year prior to the explosion. Almost half of these fatalities were due to fires or explosions ensuing process fluid releases. A very serious explosion affected the complex in July 1979, when hydrocarbons at 265 psi (1,830 kPa) were released from a failed 12 inches (30 cm) elbow in the depropanizer overhead condensing system of the sulfuric acid alkylation unit. More than 4,000 US gallons (15 m³) of liquids were discharged. A large vapor cloud formed and traveled downwind about 640 feet (200 m) to the fluid catalytic cracking (FCC) unit, where ignition occurred. A control building, the alkylation unit, the FCC unit, and the carbon monoxide boiler sustained heavy damage. Windows were broken up to 1.5 miles (2.4 km) away. Although no fatalities occurred, property loss was very significant ($24 million, or $104 million in 2024). Another large explosion took place in March 2004. Although no one was injured, BP temporarily evacuated the refinery. The police closed the access roads and asked residents not to leave their houses.

The plant had been poorly maintained for several years. Starting in the early 1990s, Amoco and later BP made substantial budget cuts, especially affecting maintenance expenditure. Immediately after the merger, in fact, BP ordered a 25% cut in operating costs, which was achieved in part with lower spending in maintenance and training and cutting back on safety staff.