Energetic material is what Wray said was being used.
Come on now Wray...firecracker? saltpeter? sparkler?
Nutter is old enough to remember Captain Kirk teaching all of America how-to make homemade black powder shooting it through a bamboo tube at the evil lizard Gorn. ;-)
Spock: he knows doctor - he knows....
So road side flares stuffed in a pipe with some wires and a digital clock attached. Not a real bomb but just something made to look like a bomb.
Standard Bureaucratic BS. Want to make this look more serious then it actually is so they can posture for the cameras. If they told the truth this story would be a big nothing.
Kinda like this?
Here is a short movie on making energetic material: