Two San Jose firefighters were injured when a ceiling collapsed at a three-alarm fire at an apartment complex Thursday night, a San Jose fire captain said.

San Jose fire Capt. Lorin Engler, 52, suffered a fractured vertebra in his neck and a concussion when a ceiling collapsed on him while battling a fire at 938 Willow Leaf Drive that was called in around 8:25 p.m., San Jose fire Capt. Reggie Williams said.

He was treated at a hospital where he remains Friday afternoon in stable condition, Williams said.

Fellow firefighters and the fire captain's family have been visiting the 16-year veteran him at the hospital around the clock, Williams said.

A second firefighter, Capt. James Cowan, an 18-year veteran, was also injured in the same ceiling collapse.

He was hospitalized with neck pain. He was treated at the hospital and has since been released and is resting at home, Williams said.

Two of the building's six units were destroyed in the blaze, while two others were damaged. The entire building has been deemed uninhabitable, displacing 18 residents, Williams said.

The American Red Cross is assisting residents affected by the blaze, Williams said.

The fire was under control at 11:24 p.m., fire officials said.

A resident was also transported to the hospital for medical reasons not caused by the fire, according to fire officials.

While the cause of the fire has not been determined, Williams said the fire is believed to be accidental.

Fire investigators received reports that residents were using a fireplace before the fire sparked, Williams said.