The damage to Family Dollar would have been significantly less had a sprinkler system been installed in the ceiling, Steiner said.
Damage to Food Lion, on one side of Family Dollar, and to the Goodwill store on the other side, was slight because a firewall separated the stores and kept the blaze from spreading, Steiner said.
The heat from the blaze was so intense it caved in the roof at the back of Family Dollar, causing the back wall to lean forward, Steiner said.
"It's been a while since we've had one this hot," he said.
Steiner said he did not know if sprinklers are required in Morgan County and referred questions about the building code to the state fire marshal's office. A state fire marshal could not be reached for comment.
An investigator is expected to arrive Saturday to determine the cause of the blaze, Steiner said.
Firefighters were dispatched at 6:52 p.m. Wednesday to the blaze at Family Dollar. When they arrived at 6:56 p.m., they found the building filled with smoke, heat and flames, Steiner said.
"I sent a team in to do an interior attack and the heat drove them out. I said, 'Well, we've got to try again.' They tried three times and said that it was too hot," Steiner said.
Firefighters got the blaze under control in about four hours and stayed on the scene most of the night to make sure there were no flare-ups.
Outside, the heat was high enough to melt the vinyl ceiling tiles on the covered walkway above the store's front doors.
"We had the melting plastic dripping down on top of us," Steiner said.
Other tiles hung Thursday from their support rods like sheets on a clothesline.
One firefighter was treated for smoke inhalation and a Family Dollar employee was treated after hyperventilating, he said.
Food Lion Manager Terry Wilson said he did not know how long Food Lion will be closed.
"We just have no idea," Wilson said.
Yellow fire scene tape closed off the area outside the supermarket and Family Dollar on Thursday.
Kathy Wolfe, 44, who lives outside Berkeley Springs, said she drove up to Food Lion to figure out how long the store will be closed.
She and other residents either will have to go to the smaller, Junior's Food Market, in Berkeley Springs, or leave the county to do their grocery shopping, Wolfe said.
Jo Ann Mowen, regional manager for Goodwill, said she did not know how long that store would be closed. She said the fire caused smoke damage to the clothes and shoes kept in her store.
"Soot dropped on a lot of things," she said. "We've got a lot of smoke to clean up."
Frank Trujillo, owner of a pizza shop in the shopping center, said smoke entered his business. He was still open for business.
"We had to throw away a lot of food," Trujillo said. "We had to clean everything."
Whale of a Wash remained open Thursday, but the hair salon in the center was closed.