The Texas City Refinery is the second-largest oil refinery in the state and the third largest in the United States. The explosion occurred in a unit where light and heavy gasoline components were being separated, and octane was being added. Due to operator error, gasoline was forced in to a pressure release system called a blow down drum. The pressure was too much and overwhelmed it, resulting in liquids spilling out and accumulating on the ground, which created a highly flammable and combustible vapor cloud. The hydrocarbon vapor cloud was then ignited by a nearby contractor’s pickup truck. The report identified numerous failings in equipment, risk management, staff management, working culture at the site, maintenance and inspection and general health and safety assessments.