A spokeswoman for the Texas State Fire Marshal’s Office on May 6 said that ammonium nitrate was the likely cause of the explosion at the West Fertilizer facility in West, Texas. The April 17 blast left 15 dead, injured more than 200, and destroyed nearly 150 homes and businesses in the small Texas town.
Authorities were still trying to determine what caused the fire that preceded the explosion, however, and said the investigation will likely extend for another 1-2 weeks. The Fire Marshal’s Office had initially said its investigation into the cause of the fire and blast would be completed by May 10. Federal investigators from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) and the Chemical Safety Board (CSB) are also on the scene.
Many fertilizer industry sources had speculated almost immediately that the explosion at West Fertilizer had been caused by ammonium nitrate, given the scale of the blast, which registered as a 2.1-magnitude earthquake and left a crater 93 feet wide and 10 feet deep. According to documents filed by West Fertilizer with the Texas State Department of Health Services in 2012, the company had total storage capacity for 270 tons of ammonium nitrate and 110,000 pounds of anhydrous ammonia.
It has not yet been disclosed how much ammonium nitrate and anhydrous ammonia was on hand at the time of the explosion. Fire Marshal officials said the fire apparently started in a seed and fertilizer building at the site, and that the ammonium nitrate was stored in bins within the building.
It was also reported by The Dallas Morning News that West Fertilizer carried just $1 million in liability insurance, which was provided by United States Fire Insurance Co. Several negligence lawsuits have been filed against Adair Grain, the parent company of West Fertilizer, by West residents and by insurance companies representing damaged businesses. The Insurance Council of Texas has estimated that damages to surrounding homes and business will exceed $100 million.