do you have a link to a report saying bomb?
According to Fox...it was a FIRE to begin with...the explosion happened 50 minutes later....
The town’s volunteer firefighters responded to a call at the plant about 6 p.m., said Waco police Sgt. William Patrick Swanton. Muska was among them, and he and his colleagues were working to evacuate the area around the plant when the blast followed about 50 minutes later. Muska said it knocked off his fire helmet and blew out the doors and windows of his nearby home.
Five or six volunteer firefighters were at the plant fire when the explosion happened, Muska said, and not all have been accounted for.