Investigators said at a press conference Thursday that the cause of the deadly West, Texas explosion was still undetermined.
Investigators said three potential causes of the explosion could not be ruled out. Those the 120 volt electrical system in the plant, a golf cart in the plant, and a fire that was intentionally set.
The golf cart could not be eliminated as a cause because, according to investigators, not enough of it was left after the explosion to definitively say it did not cause the fire.
Investigators have been searching a 93-foot wide crater since the explosion looking for evidence. Most of the evidence was found within a half mile of the crater, but one piece of evidence from the plant was found two and a half miles away.
Authorities would not rule out criminal activity and said the investigation into the cause of the explosion is still ongoing.
In the April 17 explosion 14 people lost their lives. The explosion was equivalent to between 15,000 and 20,000 pounds of TNT.