Firefighters from three neighboring counties were called in to help battle a massive six-alarm blaze in Alexandria on Monday afternoon.
It took more than 200 firefighters four hours to get the blaze under control.
Crews were called to the former Washington Examiner plant around midday for reports of a fire. Not long after they arrived, the roof partially collapsed, News4's Northern Virginia Bureau Chief Julie Carey reported.
Greg Beard was working in the building next door when the blaze began.
He recorded video on his iPhone, capturing the sound of an explosion. And as firefighters approached the warehouse, there was another frightening moment.
"The most dramatic scene was when a captain yelled down the parking lot to firemen to back out, get out, and within 30 seconds a roof collapsed and I saw firefighters run straight backwards," Beard said.
The warehouse, located at 801 S. Pickett Street, now contains a construction company and several other businesses. Those businesses were closed for Labor Day.
No injuries have been reported.
Firefighters trained hoses both from above and below on the section of the warehouse where the fire was contained. Crews were also called in from Arlington, Fairfax and Prince George's counties.
At a nearby apartment complex, residents spent their Labor Day watching the fire-fighting battle, and the towering column of smoke drew dozens of spectators who had been passing through.
"I saw it from the street and figured I'd get a closer look because I was headed this way anyway," said passerby Kurt Orban. "It's pretty dramatic."
Huge plumes of black smoke from the fire could be seen for miles; even News4's City Cam in Northwest D.C. captured video of the smoke billowing from the scene.
Van Dorn Street was closed for more than six hours, fogged in with smoke, Carey reported. It reopened around 5:45 p.m.
The biggest immediate worry for firefighters was the water supply.
Earlier in the day, a water main at S. Pickett Street and S. Van Dorn St. had broken, and the water was still cut off to part of the area around the warehouse.
Officials had to create a workaround for water, but said there's plenty of water to fight the fire.
Stay with NBCWashington on-air and online for more on this developing story.