As I remember Congressional testimony, “spreading gasoline” was “suggested” by FBI investigators as a “possibility”. What came to light was Janet Reno signed off on replacing the compressed air propellant they used to gas the place with propane. When the flash bangs went in, the place went up.
IIRC, also, when flash bangs are going in, it is normal to move LEO’s forward to quick entry position. The FBI pulled back.