Investigators have announced that the April 17, 2013 blast at a fertilizer plant in West, Texas, was caused by a fire set intentionally.
Officials with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) said the explosion was a criminal act, according to the Houston Chronicle.
The fertilizer plant, owned by Adair Grain Company, exploded just 14 minutes after the first 911 call was placed.
The explosion resulted in the deaths of 15 people, damaged 37 blocks of the town, and caused $230 million in damages. The casualties included 12 first responders.
Had the explosion occurred earlier in the day, the U.S. Chemical Safety Board concluded in January that many more people would have died because a school was in session nearby.
The blast caused an earthquake of magnitude 2.1 and destroyed 500 homes. Out of a population of 2,800, 200 people were wounded.
“It was like a nuclear bomb went off,” West mayor Tommy Muska said, according to CNN.
West Fertilizer Company, which ran the plant, told local and state officials they were storing 270 tons of flammable ammonium nitrate on site. But they failed to inform federal authorities.
“It resulted from the failure of a company to take the necessary steps to avert a preventable fire and explosion and from the inability of federal, state and local regulatory agencies to identify a serious hazard and correct it,” said U.S. Chemical Safety Board Chairman Rafael Moure-Eraso on the first anniversary of the explosion.
The company had been cited twice already by federal regulators since 2006.
A large number of lawsuits are pending against Adair Grain Company and other firms, and plaintiffs include the city of West.
Robert Elder, the ATF special agent in charge of the investigation, said May 11 that the plant’s owner had been cooperative during the inquiry, which cost $2 million to complete and included conducting 400 interviews and analyzing evidence in labs.
West Fertilizer is no longer in business.
Investigators would not say if they have a suspect. However, they are offering a reward of $50,000 for any information which leads to an arrest.