The fertilizer plant that exploded on in West, Texas in April, wiping out part of a small Texas town and killing at least 14 people, had last year been storing 1,350 times the amount of ammonium nitrate that would normally trigger safety oversight by the U.S. Department of Homeland Security (DHS).

And while state regulatory officials were aware (assuming they read the filings from the fertilizer plant) of the massive quantity of ammonium nitrate and anhydrous being stored at West Fertilizer, it wasn't their job to notify the DHS.

McClatchy reports:

A 2006 permit application to the Texas Commission on Environmental Quality noted the facility had the capacity to process up to 2,400 tons of ammonium nitrate. In 2012, West Fertilizer informed the Texas Department of State Health Services that 270 tons of ammonium nitrate and 55 tons of anhydrous were on hand at the facility. Those figures never went reported - state officials were not required to do so - to the federal Department of Homeland Security, which has kept a database of fertilizer storage spots following the 1995 Oklahoma City bombing. In that attack, which killed 168, Timothy McVeigh and Terry Nichols constructed a bomb using roughly 5,000 pounds of ammonium nitrate fertilizer. Under Homeland Security rules, fertilizer facilities must report their quantities when they have at least 400 pounds of ammonium nitrate. The 270 tons West Fertilizer reported to the Department of State Health Services is 1,350 times that amount. One of the firefighters who died in the explosion was a company foreman, and a spokeswoman for the State Fire Marshal's Office, the lead state agency in the investigation, told the American-Statesman Monday that the West Fire Department had a copy of an annually filed report, known as a Tier II report, that lists hazardous materials at an industrial site - including the ammonium nitrate. But whether individual firefighters knew about the ammonium nitrate remains an open question. If they had, they might have stood down instead of attacking the fire - as firefighters did during a fire at a fertilizer site on the outskirts of Bryan in Brazos County in 2009. Water can exacerbate conditions around ammonium nitrate. In that incident, sparks from a welder's torch probably led to the fire, said Chuck Frazier, emergency management coordinator for Brazos County. Having consulted a report detailing hazardous supplies and their quantities, the firefighters chose to evacuate much of Bryan and allow the fire to burn itself out, Frazier said. "We were fortunate not to have an explosion."

The U.S. Occupational and Safety Health Administration (OSHA) last investigated West Fertilizer in 1985. Inspections are based in part on the level of risk that plants like West Fertilizer report to the Environmental Protection Agency (EPA).

But because West Fertilizer's federal risk management plan didn't mention the risk of fire or explosion, West Fertilizer was not a priority for OSHA.

A U.S. Senate panel will probe the West Fertlizer Plant explosion. Senator Barbara Boxer the head of the Senate Environment and Public Works Committee, said the panel will hold a hearing "in the near future" on the disaster and will probe whether there are any gaps in the enforcement of U.S. chemical safety laws.

"I cannot rest until we get to the bottom of what caused the disaster in West, Texas and the tragic loss of life," Boxer said in a statement. "It is critical that we find out how this happened."