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Safety

Investigation Of Ammonium Nitrate Blast In Texas Is Closed

U.S. Chemical Safety Board faults company, regulators in fatal incident

by Jeff Johnson
February 8, 2016 | APPEARED IN VOLUME 94, ISSUE 6

Explosion
Credit: Mark Wingard/CSB
Little remains of the West Fertilizer Co. retail store and warehouse after an ammonium nitrate explosion in 2013.

The U.S. Chemical Safety Board late last month closed the books on what CSB Chair Vanessa Allen Sutherland called “one of the most destructive explosions it has ever investigated.” The West Fertilizer Co., a retail farm supply warehouse in West, Texas, caught fire and blew up nearly three years ago. Fifteen people were killed, 260 were injured, and much of the small rural town of 2,800 was flattened. Twelve of the dead were emergency responders unprepared for an accident of such magnitude, CSB said.

In the April 17, 2013, incident, about 27 metric tons of fertilizer-grade ammonium nitrate caught fire and exploded. As part of its probe, CSB found 19 similar retail facilities in Texas located near homes and schools with the potential to become another disaster. Nationally, more than 1,300 retail facilities sell and store ammonium nitrate, CSB said.

Over the years, ammonium nitrate fertilizer explosions have continued in the U.S. with disturbing regularity. In its 262-page staff report on the West accident, which was approved by the board at a community meeting in Texas, CSB cited 32 similar incidents going back to 1916. Collectively, the accidents killed 1,477 people.

Without improvements in federa, state, and local safety regulations, emergency response training and action, and land-use planning, Sutherland warned that other West-like accidents could erupt.

“Our report found that limited regulatory oversight, poor hazard awareness, inadequate emergency planning, and the facility’s proximity to nearby homes, schools, and other buildings all led to the incident’s severity,” Sutherland said. “The proposed safety recommendations address steps needed to help prevent a similar tragedy in the future.”

Several of the board’s new recommendations for regulatory changes echo CSB recommendations made more than a decade ago. Those have been ignored by regulatory agencies. By law, CSB is limited to investigations, recommendations, and analysis. It has no regulatory authority.

The accident in West occurred just before 8 PM, 20 minutes after a fire was reported and as volunteer firefighters were setting up water hoses and slowly entering the warehouse. They faced 15-meter-high flames and were trying to determine whether they should save the structure or let it burn. They were unaware that ammonium nitrate has the potential to explode under certain conditions.

The explosion damaged more than 150 buildings tens of meters away, including three schools, a nursing home, and apartment building. It completely destroyed the warehouse, which was owned by Adair Grain Inc. Fortunately, the accident occurred when nearby schools were closed or the death toll would have been much higher, CSB said.

The ammonium nitrate fertilizer was stored in large plywood bins adjacent to a room containing seeds, all flammable organic material that helped fuel the fire. The warehouse lacked a fire sprinkler system that could have slowed or stopped the fire’s spread. The warehouse stored 36 to 55 metric tons of ammonium nitrate. Another 90 metric tons was in a railcar next to the warehouse but was not affected.

After the explosion, Adair Grain filed for bankruptcy. The facility was insured for $1 million. CSB estimates the total insurance-related losses in West to be around $230 million and federal disaster assistance exceeded $16 million.

Among its recommendations, the board urged the Environmental Protection Agency and the Occupational Safety & Health Administration to add fertilizer-grade ammonium nitrate to existing safety regulations for highly hazardous chemicals. EPA does not cover ammonium nitrate under its Risk Management Plan standards, and OSHA does not cover the chemical under its Process Safety Management requirements. Nor does OSHA clearly cover fertilizer-grade ammonium nitrate in its standards for explosives, CSB noted.

CSB made similar recommendations in 2002, suggesting that the two agencies add a class of reactive chemicals, including ammonium nitrate, to their regulations. EPA and OSHA have not done so.

The board noted that after the West accident, President Barack Obama called for an examination of new approaches to toughen industrial safety regulations. However, that federal effort has stalled and so far has not moved beyond issuing guidance and advisory documents. It is unlikely to lead to formal regulatory proposals as Obama’s Administration winds to a close.

CSB urged new facilities to use noncombustible construction materials and fire suppression systems and recommended new emergency responder training. The board also said it intends to conduct a national investigation of land-use planning decisions near industrial areas. However, Sutherland said, that study has yet to get under way.  

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