Deanne Stein, News9.com

OKLAHOMA CITY -- Oklahoma City firefighters battled a commercial fire for nearly 16 hours. The fire started early Sunday morning in a building that housed three businesses near N.W. 4th Street and Pennsylvania Avenue.

The building housed Southland Flooring Supply Company, Huston DePue and Force Staffing. Force Staffing is OK, but the other two businesses sustained the most damage, forcing these managers and owners to start over.

Linda and Mike DePue own Huston DePue, a calibration lab for industrial electronic equipment that's been in the family for four decades.

"It was very shocking because we've been coming to this front door for 40 years, since I was a little girl," said Linda DePue, owner of Huston DePue. "It was really hard to look at it."

The business received heavy smoke and water damage. But for Southland Flooring Supply Company, where the fire started, it's considered a total loss.

"It was hard to see the men that have invested their lives here, have their businesses burn up," said DePue.

Oklahoma City firefighters have had the heavy task of putting out the hot spots, that continued to burn more than 12 hours later.

"It's very dangerous because of the type of material they have," said Battalion Chief Al Cothran, Oklahoma City Fire Department. "Everything is extremely combustible, flooring, glue, things like that. Very hazardous when it burns."

Firefighters contained the blaze to the Northeast corner of the building, where part of the roof collapsed.

"We have heavy equipment out there tearing down walls and pulling roofing materials out so we can hit all the smoldering material," said Cothran. "That's the only way we can get to it."

As for the business owners, they hope to rebuild and start over.

"We'll be down awhile and take care of our employees," said DePue. "And we'll just ask God for wisdom on how to put this back together and get up and running again."

According to the fire department, the building sustained $400,000 in damages and as far as the contents within both businesses, those losses totaled $800,000 The cause of the fire is still under investigation.