The fire broke out at the plant in Winston-Salem, where more than 6,000 people within a mile of the plant were told to leave over worries of a possible explosion.
Thousands of people were ordered to evacuate from a neighborhood in Winston-Salem, N.C., on Tuesday as the authorities warned of a possible explosion from a fire burning for a second day at a nearby fertilizer plant.
More than 600 tons of ammonium nitrate were at the Winston Weaver Company plant when the fire broke out on Monday night, the city’s fire chief, Trey Mayo, said in a news conference on Tuesday. He compared it to a fire at a fertilizer plant in Texas in 2013, in which 240 tons of the same product exploded, destroying or severely damaging nearly 200 homes and killing 15 people.
“If that doesn’t convey the gravity of the situation and how serious folks need to take it,” he said, “I don’t know how else to verbalize that.”
Asked by a reporter how much of the chemical was “in the line of fire” on Tuesday, Chief Mayo said, “all of it.”
It was not clear what caused the fire, which broke out at the plant on Monday night. The Bureau of Alcohol, Tobacco, Firearms and Explosives said on Tuesday that federal investigators were assisting local fire departments.
Denise D. Adams, a Winston-Salem City Council member who represents the North Ward district that includes the plant, said in an interview on Tuesday that about 500 tons of the chemical was in the building and the rest on a rail car, with tons of finished fertilizer product also on-site.
She said she had been watching television on Monday night when she heard sirens. At around 7 p.m., she recalled, “there was a loud shaking explosion, boom, and immediately my mind thought when I heard it — fertilizer plant.”
The blaze started at a loading dock, she said. Multiple calls had come in to 911 by people passing by the plant.
Firefighters who responded to the blaze on Monday were later pulled off the job because the building where the ammonium nitrate was stored had collapsed, limiting their ability to get enough water into the area, Chief Mayo said.
On Tuesday, the department posted a video showing firefighters deployed in the neighborhood, calling for the approximately 6,500 residents living within a one-mile radius of the plant to evacuate.
“If it explodes, it’ll level a one-mile radius,” a firefighter said, speaking through a loudspeaker from inside his vehicle on the darkened streets. “Please exit the area.”
North Hills Elementary School, which is within the evacuation zone, was closed and had switched to remote learning instead. Wake Forest University canceled class on Tuesday and encouraged faculty members, staff members and students who live inside the area to leave. Some university property, including a student housing center, lies inside of the zone.
Chief Mayo said personnel teams, helicopters and drones had been enlisted in efforts to monitor and combat the fire. He added that the authorities had made a “calculated risk” to take firefighters out of the direct line of danger.
“We will be able to make some more active decisions after we have surveillance,” he said.
He said that they were “not out of the woods yet” in terms of the risk of an explosion taking place. The risk would diminish about 36 hours after the fire broke out, and about half of that time had elapsed as of Tuesday morning, he said.
An explosion of ammonium nitrate would occur from a combination of weight and heat, he said. The chemical has to be confined to explode, he added, and when there is a large quantity of it, the amount on top acts to confine the amount underneath, the chief said.
No injuries or deaths have been reported. It was not immediately clear how many employees worked at the plant. The company was founded in Norfolk, Va., in 1929, and it opened the Winston-Salem plant in 1940. Representatives for the Winston Weaver Company could not be reached on Tuesday.
Ms. Adams, the City Council member, said that the plant had undergone an inspection in December, and that “there was no noncompliance” issue at the plant.
She said a shelter had been opened at a nearby fairgrounds but that the evacuation order, meant to last for 48 hours, was voluntary.
It was not immediately clear what caused the fire at the plant, Ms. Adams said.
The fire that set off one of the worst industrial disasters in Texas history — the deadly explosion of the plant in West, Texas, in 2013 — was intentionally set, federal officials said.
The Occupational Safety and Health Administration, the federal agency that regulates workplace safety and the storage of chemicals, told the fertilizer industry in a letter after the disaster in Texas that the explosion of bulk ammonium nitrate took place 20 minutes after the first report of a fire.
