From your link:
Market sources said the explosions and subsequent fire occurred in an iso-octane unit on the west side of the complex, near several storage facilities. Those also are near a liquefied petroleum gas (LPG) pipeline.
The storage facilities, which Enterprise acquired in 2001, consist of 30 salt-dome caverns with a total capacity of 77m bbl, according to the companys website.
I'm going to cease and desist for now until more is known.