While we don't know what caused the West Fertilizer plant to explode, we do know two key facts about it. First, this was a criminal act, by virtue of this company lying to state and federal regulators about the chemicals it had on site and not having even rudimentary safety equipment. Second, the contributing cause of the explosion was Texas' bad joke of a regulatory scheme.
Consider what we already know. This plant was built in a town that had no zoning plan--meaning it was possible for houses, apartments and a school to be built next to a plant that had anhydrous ammonia and ammonium nitrate on site. Security at this plant was almost nonexistent, even though local meth-heads regularly stole ammonia from it. And the plant was allowed to operate with only $1 million in liability insurance--and theoretically could have stayed in business without any liability insurance at all.
I'm all for creating an environment that is friendly for business. But at the same time, if having common-sense regulations that keep workers and the general public safe is considered "burdensome" and unfriendly to business, there is something fundamentally wrong. Sadly, it looks like 30 years of "regulation bad, regulation bad" thinking have finally come home to roost.