At the earlier stages of this incident, TV Stations were reporting this to be a possible transformer explosion.
Later it was learned to be a rented van with a homemade propane (?) bomb in it.
Here is a video of this 1993 WTC Bombing. Up until this time, as I remember it, this was reported to be one of the largest operations in the FDNY History.
a couple of weeks after TL111 did a Multi-Floor Secondary Search/Inspection there a certain
Lt. told some friends & I - 'If That Place ever get's Hit again; it's gonna' go up like a
Roman Candle - you wouldn't believe what they (Gov't.) has stored in there...' [Highly Combustible & Explosives]