UPDATE 5 PM TUESDAY: The fire that critically injured a Fort Sanders man in his home Saturday was accidentally set, according to the Knoxville Fire Department.

The 52-year-old man was being treated Tuesday at the Vanderbilt Burn Center at Vanderbilt University Medical Center in Nashville.

Fire broke out about 7:30 p.m. Saturday inside the upper unit of the four-plex. The man was pulled unconscious from the floor once firefighters forced their way inside.

"Knoxville fire investigators have determined the fire started near or around a couch in a front room, possibly by carelessly maintained or discarded smoking paraphernalia," a release Tuesday from fire Capt. D.J. Corcoran states.

KFD has not released the man's name.

PREVIOUS STORY: A 52-year-old man pulled unconscious from a residential fire Saturday in the Fort Sanders neighborhood was being treated at Vanderbilt Burn Center at Vanderbilt University Medical Center in Nashville, according to the Knoxville Fire Department.

KFD has not released the man's name. The cause of the fire is under investigation.

Fire broke out about 7:30 p.m. Saturday in the two-story, fourplex unit at 1210 Clinch Ave. Fire Department units arrived in less than three minutes, records show.

Source: KFD

Black smoke and flames began pouring from the upstairs front window.

Firefighters found the man inside at the top of the stairs, according to the report.

KFD spokesman Capt. D.J. Corcoran said Monday the man was first taken to University of Tennessee Medical Center and then moved to the burn center.

The fire appeared to break out in the unit, and the cause remains under investigation, records show.