HOUSTON (June 27, 2013)—U.S. senators Thursday demanded that the U.S. Environmental Protection Agency immediately begin regulating potentially explosive fertilizer chemicals such as the ammonium nitrate that exploded on April 17 in West, killing 15, injuring about 200 and damaging or destroying dozens of homes and buildings.
U.S. Sen. Barbara Boxer, D-Calif., chairwoman of the Senate Committee on Environment and Public Works, accused the EPA of a lack of urgency and nonchalance.
The U.S. Chemical Safety Board, which is investigating the deadly explosion in West, says the regulation of dangerous chemicals falls under a "patchwork" of standards that are decades old and weaker than those used elsewhere.
The board, which presented preliminary findings to the committee Thursday, is the first federal agency to acknowledge lax oversight of ammonium nitrate, the chemical that caused the explosion in West.
The West plant had no sprinkler systems and the chemical was stored in wooden bins.
State and federal investigators who spent weeks excavating the blast site determined that the fire that led to the powerful explosion was caused either by a battery-powered golf cart that was kept in the fertilizer and seed building in which the fire started, the building’s 120-volt electrical system or by an intentional criminal act.
As much as 64 tons of ammonium nitrate was stored in the building, 28 to 34 tons of which exploded, investigators said, while an additional 20 to 30 tons in the building and another 100 tons in a nearby rail car did not explode.
The total amount of ammonium nitrate on the site was about 150 tons, less than 270 tons that federal records indicated was stored at the plant.
By comparison, the amount of ammonium nitrate that exploded on April 17 in West was about 12 times the amount used in the truck bomb that blew the side off of the Albert P. Murrah federal building on April 19, 1995 in Oklahoma City.
The fire actually caused two explosions, just milliseconds apart, Assistant State Fire Marshal Kelly Kistner said.
The first, which was the result of some combination of heat, building pressure from containment and shock from falling debris and equipment, triggered the second larger blast, he said.
The Chemical Safety Board says guidelines for firefighters on how to fight such a blaze are vague.