A 45-year-old woman was killed and her husband and two daughters were seriously burned yesterday when an early morning, two-alarm fire swept through their Northwest Washington home, D.C. Fire Department officials reported.

Firefighters said intense heat and smoke prevented them from entering the house at 67 Quincy Place NW and rescuing Bessie Mae Duncan, whose body was found in a front bedroom on the second floor.

Duncan's husband, Roy R. Picott, 39, who fire officials said "woke up and found fire all around him," escaped from the house by jumping out a window.

Their daughters, Cheryl Picott and Martha Faye Duncan, both 19, were in their bedrooms on the second floor when the fire broke out at about 4 a.m., and neighbors said they apparently escaped through the back.

Two sons, Rodney Picott, 18, and Danny Leroy Duncan, 19, fled from their basement bedroom and were not injured, fire officials said.

It took about 85 firefighters more than 45 minutes to control the blaze, officials said. Fire investigators ruled that the blaze was accidental and caused by improperly discarded smoking materials. The cause of Duncan's death had not been determined, pending an autopsy by the D.C. medical examiner.

According to department spokesman Ray Alfred, three persons were initially reported trapped inside the two-story row house when firefighters arrived on the scene.

"The guys did a tremendous job laddering the building and trying to get inside to rescue the people," Alfred said. He said flames were raging out of the first and second floor windows, and "there was just too much fire and too much heat" to enter the house, which was not equipped with smoke detectors.

A neighbor, Tony Carpenter, 24, said he was asleep a few doors away when he was awakened by a loud noise.

"Mom and I heard a kind of 'boom,' like an explosion," he said. "She looked out and saw the father jumping out of the front window on the first floor."

Carpenter said he ran outside and saw Picott, clad in underclothes, in front of the house "hollering for someone to help him because his wife was still in there. He couldn't get through the front door because it was in flames and he was hollering inside for her."

A spokesman at the Washington Hospital Center said Picott suffered second and third degree burns over 60 percent of his body and was in critical condition. Cheryl Picott, also in critical condition, suffered second and third degree burns over 38 percent of her body, and Martha Faye Duncan, in fair condition, received second and third degree burns over 15 percent of her body, he said.

Fire spokesman Alfred said that it gradually became apparent that only the mother was unaccounted for, and neighbors who had waited in hopeful clusters outside the house broke into tears when her body was discovered about daybreak.

One woman, A.E. Best, who lives two doors away, described Bessie Mae Duncan as a generous and friendly woman who enjoyed tending a small vegetable garden in her back yard and often would pass out tomatoes to neighbors.

"She was also a good cook," Best said. "Last Christmas, she sent over a cake, just like she did every Christmas."

Damage from the blaze was about $65,000 to Picott's house and $15,000 to the houses on either side of it, Alfred said.

A spokeswoman for the department said Duncan's was the first fire-related death in the District in 1985 and the seventh civilian death since Oct. 1, the start of the fiscal year. One firefighter has died since Oct. 1, she said.

During the same period last year, she said, there were eight fire-related civilian deaths and one of a firefighter.