Firefighters probably could not see Orellana when they initially entered the unit, Talmadge said.
Orellana was lying face down and unresponsive when firefighters discovered him, according to the medical examiner's report. That's when the 20-minute effort to get him out of the building began.
Talmadge said several factors complicated the rescue attempt: the simultaneous efforts to get other residents out of the building, concerns that the roof was about to fail (it did) and, not least, the victim's size.
Orellana was 5-foot-10 and weighed 263 pounds. Talmadge said firefighters labored to carry him down from the third floor and out of the building.
More than 200 firefighters battled the four-alarm fire, which caused $8.6 million in damage to a structure that housed residential and commercial spaces.
The fire, deemed unintentional, started inside a wall, the Fire Department says. Investigators have said they believe some sort of electrical failure may have caused the blaze.
The fire was "most likely accidental and originated in the third floor south/west hallway within the west stud wall with fire extension to and throughout the common attic space," according to a Fire Department report about the blaze.
The fire was the first fatal blaze in the city this year. That blaze, and a series of others, have prompted two San Francisco supervisors to consider legislation that would increase the number of sprinklers in the city's older apartment buildings and improve enforcement of the fire code.
The building where Orellana was killed had no sprinkler system, which the city did not require, and its smoke detectors did not work properly.
There was a hard-wired, electric-powered smoke detection system in the building at the time that failed to work correctly, Talmadge said. She said it was possible the same electrical problem that may have caused the fire might have made the smoke detectors inoperable.
In the days after the blaze, KQED learned that several exits in the building were blocked.
The blaze led the fire marshal to acknowledge weaknesses in the Fire Department's recording of safety problems in the city's apartment buildings.
Last September, a five-alarm fire a block away burned a commercial building that did not have sprinklers.
Two members of a family suffered fatal injuries in an apartment fire at 24th Street and Treat Avenue in March.
The most recent fatal fire in San Francisco took place in North Beach. That blaze killed a man on Columbus Avenue in early April.
Dan Brekke of KQED News contributed to this report.