The West, Texas fertilizer plant that exploded on Wednesday, killing dozens, was only supposed to have had less than 400 lbs of explosive ammonium nitrate — instead, it had 270 tons of the substance. 400 lbs is the threshold where the plant would have had to inform the Department of Homeland Security about the amount of explosives it had. Unfortunately, DHS didn't even know the plant existed.

"This facility was known to have chemicals well above the threshold amount to be regulated under the Chemical Facility Anti-Terrorism Standards Act (CFATS), yet we understand that DHS did not even know the plant existed until it blew up," Rep. Bennie Thompson (D-MS) said in a statement.

On top of that, the plant, whose explosion registered on the Richter Scale, did not have any sprinklers, firewalls, or water deluge systems, according to the AP.

Facilities like the fertilizer plant fall into a regulation-loophole.

The AP writes,

No federal agency determines how close a facility handling potentially dangerous substances can be to population centers, and in many states, including Texas, many of these decisions are left up to local zoning authorities.

The fertilizer plant was less than 3,000 feet from a school. Officials have yet to release a cause for the explosion.