DALLAS, Texas -- KVUE's sister station WFAA has learned the building that was the epicenter in Wednesday night's blast in West, Texas, was used to store ammonium nitrate fertilizer.
Ammonium nitrate was the explosive used in the bombing of the Murrah Federal Building in Oklahoma City in 1995. That explosion caused federal officials to regulate who buys ammonium nitrate, but not who stores it.
Farmers near West say West Fertilizer stored ammonium nitrate and other fertilizer ingredients and custom-mixed them for farmers, a common practice in farming communities.
Intense heat can make ammonium nitrate explode, Dr. Rasika Diaz, chairman of the Department of Chemistry at UT Arlington, told WFAA.
"Beyond certain temperatures, I believe it's about 400 degrees Fahrenheit, [ammonium nitrate] can explode," Diaz said. "And it can decompose, creating an explosion. Ammonium nitrate is classified as an explosive."
Video shot on Wednesday night showed a fire raging near the storage building. Video of the blast shows the building blowing up. Shots of the scene Thursday morning show the path of the explosion emanated from the storage building.
Twelve years ago, 31 people were killed at a fertilizer plant explosion in Toulouse, France. And 66 years ago, 581 people died in an ammonium nitrate explosion in Texas City, Texas