A woman who was killed in a house fire, along with her two young sons, last week was urged the day before the fire to move out of her home in rural Charles County until her furnace could be repaired, county antipoverty officials said.

Fire marshals said the tragic blaze and at least 34 other weather-related house fires in the region last week underline the importance of taking fire safety precautions.

Nanjemoy residents Sherline Owens, 28, and her sons, Paul, 9, and Carl, 5, died early Jan. 22 after their overworked oil heater ignited the floor boards and walls of their wooden farmhouse, trapping them in the bedroom, fire investigators said.

Owens had contacted antipoverty workers the day before about burner repairs, "but none of the four major fuel companies down here could get to her, the demand was so great," said Lindy Ward Chinnault, head of emergency services for the Tri-County Community Action group in Hughesville, Md.

"We told her to please take the children and stay with relatives," Chinnault said. "We'll never know why she decided not to. . . . It's a very tragic case.".

Chinnault said the Owens case was not the worst of the more than 600 requests for home heater repairs or energy assistance her office has received since the Washington area plunged into a deep freeze Jan. 20.

"We've had several other clients we've had to tell 'drain the pipes and leave.' Then it becomes a shelter issue and a whole separate problem," she said.

Fire investigators said Owens had put out a furnace fire in her home earlier in January and had turned the heater off Tuesday after telling neighbors that it was "glowing red hot," said Robert Cleveland, an investigator with the state fire marshal's office in Charles. "Apparently, it got so cold she turned it back on."

"We had seven house fires including the Owens' fire between Monday and Wednesday due directly to the frigid weather," Cleveland said. He said the causes included homeowners "overworking their electrical or oil units or wrapping cloth and light bulbs around their water pipes to keep them from freezing up."

In another fire late Thursday, a faulty kerosene heater exploded in a mobile home while a southern Prince George's County woman was on the telephone in the same room. The woman escaped, but the trailer was badly damaged and the family cat died in the blaze, firefighters said.

In addition to the fires blamed on faulty furnances, 19 chimney fires were reported between Jan. 20 and last Monday, Charles County fire dispatcher Alton Hancock said.

"Because of the cold, people are using their heat sources more intensively and the weak components may fail," Cleveland said.

In the wake of the outbreak of weather-related fires, officials are urging residents to use only legal models of propane and kerosene heaters, to inspect all furnaces for wear and tear, and to burn seasoned hard woods in their wood-burning stoves.

"The green wood and pines -- which a lot of people around here burn when they get desperate -- gives off much more oily creosote and builds up in chimneys and stove pipes," Hancock said.

"Woodstoves with inserts and fans to circulate the warm air should be checked more often for creosote build up, especially if it's the only heat source," said Glen Robey, a firefighter with the Nanjemoy Volunteer Fire Department.

County firefighters -- who also answered about 100 calls for help with broken water pipes last week -- cautioned residents about taking a blowtorch to frozen pipes. "It's safer to use a hair dryer," said Waldorf firefighter Thomas Edwards.

Chinnault said the oil companies serving her low-income clients in St. Mary's, Charles, and Calvert assigned crews to work around the clock to keep up with customer demand.

"We got about 2,000 calls for repairs," during the first four cold days, said Southern Maryland Oil's general manager Joseph Schmansky, whose company serves 24,000 business and residential customers.

Fire marshal Cleveland said that when pressed for funds many people let their service contracts lapse on home furnaces -- "if they ever had them."

Norman A. Norris, vice president of Besche Oil Co. in Waldorf, where repair requests last week were triple the normal number, said his biggest problem was with customers who decided to regulate their fuel supplies themselves rather than have the company make automatic refills at regular intervals.

"Many people are managing by crisis. They are letting their inventories go very low to save money," he said. "When they call us they exaggerate their situation and say they don't have any heat. We can't take any chances, but we often find out that's not the case when we get there."