WINSTON-SALEM, N.C. — A fire at a fertilizer plant in Winston-Salem continues to burn after more than 20 hours. The company that owns the plant said no one was hurt in the fire. 

The situation remains dangerous around a large Winston-Salem fertilizer plant fire because an explosion remains possible

Emergency officials said the 6,500 people who live within a mile of the plant should evacuate 

The blaze could continue to burn for days and is creating some air quality issues

Emergency officials said the 6,500 people who live within a mile of the plant should evacuate. That evacuation zone will likely continue until 7 p.m. Wednesday as the fire keeps burning.

Because of the amount of ammonium nitrate at the plant, Fire Chief Trey Mayo said, “this is potentially the largest explosion in U.S. history.” 

The evacuation is not mandatory. But, the chief said, when people see the fire department pulling back, they should probably get out too.

“We are not out of the woods yet,” he said. 

A massive column of smoke continues to rise from the plant, which caught fire at about 6:30 p.m. Monday. The fire department initially began fighting the blaze until the department realized just how much ammonium nitrate was at the plant. 

There is about 600 tons of ammonium nitrate on the site, including 100 tons in a train car. 

A fertilizer plant fire in West Texas had about 150 tons of the chemical when it exploded in 2013, killing 15 and flattening homes around the site, Mayo said. 

The chief said it doesn’t look like the fire is threatening the rail car as of about 4 p.m. Tuesday. He said the fire is smaller than it was this morning as the building burns, and more of the ammonium nitrate burns off.

It could take at least another day or up to a week before firefighters can safely go in and extinguish any remaining hotspots, Mayo said. 

There is still a risk the plant could blow up, he said. 

“We really should not get too comfortable about not having an explosion for a solid 36 hours,” he said. That would be until 7 a.m. Wednesday. 

Andrew Carroll, spokesman for Winston Weaver Co., said, “We will continue working with first responders and relevant officials to ensure safety of the community, and we will participate fully in the investigation into the cause of the fire.”

The Weaver plant was last inspected by fire officials in December, Mayo said. Inspectors did not find any problems at the site. 

The plant, parts of which are more than 80 years old, likely did not have a sprinkler system, Mayo said. 

“I don’t think there was a fire code when this building was constructed,” he said. 

Air quality

Air quality will continue to be a problem for people around the fire, northwest of downtown Winston-Salem.

The smoke could be seen blowing southwest for much of the day Tuesday, casting a haze over parts of the city and making it difficult for some to breath. 

Mayo said the wind was shifting Tuesday afternoon, and the smoke will likely shift to the northwest of the plant tonight. 

The smoke could be harmful to small children and people with lung conditions like asthma and COPD. Mayo said people in the path of the smoke should not exercise outdoors for now. 

Mayo said the smoke was “not particularly toxic” and did not have a significant amount of nitrous oxide. But, he added, the Environmental Protection Agency is on scene, and expects to share more air quality data Tuesday night. 

Schools

Winston-Salem/Forsyth County Schools had a virtual day Tuesday for North Hills Elementary students, near the site of the fire. The school will have another virtual day Wednesday. 

The school system is opening the Education Building at 4801 Bethania Station Road to North Hills students who need help with remote learning or whose parents have to work during the school day.

“We’ve lost so much instructional time over the past year, that even a few days matter for these students,” said North Hills Principal Tiffany Krafft. 

“We know that while not every student is impacted by the evacuation plan, those that are impacted may face challenges, like access to Wi-Fi or parents that must continue to work.”

Wake Forest University, which sits not far from the fire, canceled classes Tuesday. There was heavy smoke at times across much of the campus. 

The university also evacuated students living in one resident hall. The university expects the evacuation to last until at least 11 p.m. Wednesday.