The initial blast at the West Fertilizer Plant in the town of West occurred around 8:00 PM and flattened buildings and houses in the area. A local resident was filming the fire when the first explosion happened.
At least 180 people have been reported as injured, with as many as five to 15 people feared dead, Sgt. William Patrick Swanton of the Waco Police Department told ABC News. The dead include five firefighters.
Officials were searching through the devastation early Thursday morning for more survivors and were treating the site as a crime scene.
"We are not indicating that it is a crime, but we don't know," Swanton said. "What that means to us is that until we know that it is an industrial accident, we will work it as a crime scene. ATF [the federal Bureau of Alcohol, Tobacco, Firearms and Explosives] is conducting the main investigation."