Looks to me like the center of the blast location was in the North West corner of the large building. Or possibly right outside where the Trailer was parked in the Google picture.
We don’t know if there was a trailer there that day. But we do know that they park them in that location.
Implies a fork lift operation lifting pallets of fertilizer out of a trailer and into their warehouse.
7:29 pm April 17, 2012. Firefighters respond to fire.
7:53 pm “There has been an explosion”.
Whatever happened, the fire got very big, very quick.
The explosion followed 24 minutes later.