WINSTON-SALEM — Hundreds of tons of potentially explosive ammonium nitrate was improperly stored at a fertilizer plant Jan. 31 when the facility was destroyed by a fire that took days to extinguish and prompted a voluntary evacuation order impacting thousands of residents, a North Carolina Department of Labor investigation found.
The agency levied fines totaling $5,600 on Winston Weaver Co. based on information gleaned during interviews with company employees after the blaze.
That communication was crucial in determining pre-fire conditions at the site, where little remained other than ash and warped metal when investigators got their first up-close look at the scene, NCDOL spokesman John Mallow said in a phone interview Monday.
“They can communicate the substantive things deemed to be a violation,” Mallow said of the conversations with workers.
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In this case, 500 tons of ammonium nitrate, a highly explosive substance commonly used as an ingredient in fertilizer, was exposed to water leaking through the roof, walls and floor of the building where it was stored, NCDOL reported in a citation issued to the company July 18.
Investigators also determined that wooden storage bins at the Weaver facility were not adequate to keep ammonium nitrate from escaping or other substances from entering.
“It sounds like the Department of Labor is doing its job,” said Stan Meiburg, former deputy administrator at the U.S. Environmental Agency who now leads Wake Forest University’s graduate program in sustainability. “If the ammonium nitrate was stored in a way that would create risks to its employees — or first responders, as happened in West, Texas — that would be cause for enforcement action independent of the environmental consequences of the fire.”
In West, a small town between Dallas and Austin, 10 first responders and two volunteers were killed in 2013 by a powerful explosion of ammonium nitrate while fighting a fire at a fertilizer plant. The blast resulted in 15 deaths and destroyed hundreds of homes.
Officials said 20 to 30 tons of ammonium nitrate was stored at the Texas site. Nearly 17 times more was present at the time of the Weaver fire at 4440 N. Cherry St.
The potential for what Winston-Salem Fire Chief Trey Mayo feared could be “one of the worst explosions in U.S. history” prompted responders to retreat from the Weaver blaze in its early hours.
In a 2016 report, the U.S. Chemical Safety and Hazard Investigation Board insisted the Texas blast and other incidents involving ammonium nitrite should serve as a collective call to action for local, state and federal governments to do more to protect vulnerable communities.
“Despite tremendous property damage and economic cost, the most devastating result of these incidents is the immeasurable loss of human life,” the board wrote. “CSB found that a likely cause of such loss of life is the alarming number of (fertilizer-grade ammonium nitrite) facilities located in communities — next to schools, hospitals, residences and businesses.”
At the time, the board found 19 Texas facilities with at least 10 tons of stored ammonium nitrate within a half-mile of such institutions or highly populated areas.
About 6,000 residents live that close to the Weaver site, where 50-times more ammonium nitrate was kept on site at the time of the fire.
Investigators were never ever to determine the cause of the Texas fire that led to the explosion, largely because the blast left few clues for them to follow. Winston-Salem officials cited similar challenges Friday in a report noting that they were unable to find a cause for the Weaver blaze.
Mallow said NCDOL’s investigation into ammonium nitrate storage at the former Weaver plant remains open, and the company has the option to appeal the citations and fines.
The North Carolina Department of Environmental Quality last month approved plans for extensive testing to determine levels of soil and groundwater contamination at the site.
A contractor hired by the company will spend an expected four months collecting and analyzing hundreds of samples for potentially hazardous materials left behind from the fire.