Last Updated Dec 28, 2014 9:00 PM EST
CASTLE HILLS, Texas -- Five people died Sunday after a fire broke out at a senior-living apartment building in the San Antonio suburb of Castle Hills, reports CBS affiliate KENS in San Antonio.
Ten other residents of the Wedgwood Apartments remained hospitalized and others were unaccounted for Sunday evening, according to Bexar County Fire Marshal spokeswoman Laura Jesse.
Witnesses told KENS smoke could be seen pouring from the building.
A total of 150 firefighters from San Antonio and six other fire departments responded to the blaze, which was reported shortly after 6 a.m., San Antonio Fire Department spokesman Christian Bove said.
The cause of the three-alarm fire at the 11-story high-rise is under investigation, but it appears to have originated on the third floor, Jesse said. The fire, now extinguished, left some "significant damage," she said.
Not all of the 216 residents listed on the building's rent rolls have been accounted for yet, Jesse said. The building also has commercial tenants.
About 150 residents were taken by city buses to a local high school, and some family members waited at a makeshift shelter in the cafeteria for word of their loved ones. Others residents were taken to a hotel.
Property manager Entrada Management Services was arranging for the residents' stays "if they don't have anywhere else to go," Jesse said.
The names of those killed in the fire have not been released.
"After looking at the floors, it's amazing we did not have more loss of life," San Antonio Fire Chief Charles Hood said at a news conference, adding that the smoke and fire were "communicated" throughout the building. He also said the building's third floor was gutted and the doors were charred.
Some residents walked down many flights of stairs, others were carried out, and others were evacuated down ladder truckers from the balconies of their apartments, Bove said.
"It was overwhelming. We tried to come out, but the exit doors were jammed," resident Vivian Casanova told the San Antonio Express-News.
It was not immediately clear when the facility was last inspected. Castle Hills City Manager Diane Pfeil told the newspaper that she was not sure when its most recent safety inspection was but said she would have that information in the next day or two.
Red Cross staff and volunteers at the shelter helped Sunday afternoon to match residents with the medications that were recovered after the building was evacuated.
According to Bove, the last time the San Antonio area saw a fire of this magnitude was in 2008 at Our Lady of the Lake University, but no one was injured.