Deerfield Beach, Fla. – An explosion and fire tore apart a large section of a three-story apartment building Thursday, blowing out windows, partially collapsing the roof and injuring ten people.

Authorities said the cause may have been a propane explosion.

The blast occurred while most people were asleep, but all the residents appeared to have escaped. Firefighters and cadaver dogs have not found any fatalities, and the search was nearly complete.

“We’ve had separate search dogs on the third and second floors that have come up negative for any victims,” said Gary Fernaays, a spokesman for Deerfield Beach Fire Rescue.

Up to 150 residents were startled awake by the 5:30 a.m. explosion and rushed away from the structure as it burned and nearly half the roof collapsed. Firefighters quickly extinguished the blaze and swept through the charred rubble looking for potential victims.

Two 1,000-gallon underground propane tanks alongside the building were being inspected, Fernaays said.

“Blue flames suggested some type of gas so we’re thinking it’s propane,” Fernaays said.

Authorities were working to determine whether there was a natural gas leak.

Dorothy Williams, 45, said she had been dozing off to sleep when her husband came in and said, “Get up there’s been an explosion in here!”

“Once he said that, the windows started popping. There was glass everywhere. The TV started flying across the room,” she said, standing across the street after escaping with her husband and two pet birds.

Four residents were taken to hospitals for evaluation and treatment of minor injuries, Fernaays said. Six others were treated on the scene, including two firefighters. Authorities said the injuries appeared to be minor.

But the damage was extensive — several interior walls fell, and exterior walls were standing but several had cracks. Glass and debris covered cars in a parking lot.

It remained unclear when, or if, residents would be allowed to return. “The third floor is uninhabitable. We’re questioning whether the second floor is,” Fernaays said.

Another resident, Frances Boucharune, 9, said she had been sleeping when her mother woke her up to alert her to the fire.

“The roof came down and fell on my mom. She had glass all over her arm,” the girl said. Her mother had dried blood caked on her left arm.

Deerfield Beach is just north of Fort Lauderdale.

The building is among a handful of similar apartment complexes packed closely together with a strip mall, restaurant and car dealership less than a 100 yards from a highway.