Los Angeles Fire Department arson investigators look over the remains of a house fire in the Hollywood Hills section of Los Angeles Thursday, Feb 17, 2011. A firefighter was battling for his life Thursday after a ceiling collapsed at the burning home, injuring him and five others. (AP Photo/Nick Ut)

A Los Angeles city firefighter close to retirement and awaiting the impending birth of his first grandchild was gravely injured when a ceiling collapsed on him and five colleagues battling a blaze at a Hollywood Hills home, authorities said today.

"He is fighting for his life," Los Angeles Fire Department Capt. Tina Haro said late this morning. "There is no change in his condition."

The accidental blaze in the 1500 block of North Viewsite Drive, near Sunset Plaza, may have spread from a gas fireplace, Haro said.

The fire -- which also injured five other firefightres -- was reported at 11:20 p.m. Wednesday and knocked down by about 1 this morning, said Devin Gales of the LAFD.

Firefighters were inside the home when the ceiling collapsed on them, said Capt. Jaime Moore, who noted the area above the ceiling had become saturated with water. A plastic pipe providing water to the sprinkler system "burned through," causing a large amount of water to accumulate above the ceiling in the enclosed space between the ceiling and the roof, he said.

The critically injured firefighter's colleagues had to use chainsaws to gain access to him under the rubble and pull him out, Haro said. The 38-year LAFD veteran, who is about a year from retirement, was taken to Cedars-Sinai Medical Center in grave condition.

He's awaiting the birth of his first grandchild, which is expected in a couple of days, fire Chief Millage Peaks said.

Los Angeles Mayor Antonio Villaraigosa said he was "deeply saddened to learn that four Los Angeles Angeles city firefighters and two Los Angeles County firefighters were injured in the line of duty as they responded to a call near the Hollywood Hills late last night."

"One of those firefighters, a 38-year LAFD veteran, is currently fighting for his life," the mayor said. "As residents of this great city, let us never forget the men and women who selflessly put their lives at risk to protect our families, our homes, and our neighborhoods. These first responders are real-life, every day heroes who rush into the face of danger not just because it is their job, but because their devotion to the noblest of professions soars high."

A Los Angeles city firefighter was admitted for treatment of a broken ankle, and two city and two county firefighters also injured in the roof collapse were treated and released, Haro said.

Two residents had only been living at the home for about a week and escaped the fire without injuries, Gales said.

A damage estimate was not immediately available.