This explosion is VERY SIMILAR to the fatal hotwork explosion that occurred in 2001 at Motiva Enterprises. The Motiva explosion occurred when 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 the contract workers was killed; eight others were injured.
On August 4, 2009, @ 9:15 a.m. an explosion occurred inside a 100-m3 capacity tank (built in 1974) containing 96% sulphuric acid. A member of the plant staff, accompanied by 2 subcontractor employees, climbed onto the tank to open the manhole. An explosion occurred when the plant technician used a grinder to shear the seized bolts. The tank, empty at the time of the accident, was suddenly lifted 2 or 3 m high and then fell back to the ground on top of a nearby drum. As it was falling, the tank brought down the scaffolding that had been installed for upcoming maintenance.