NATICK — Firefighters forced their way through a burning hole in the second floor of a smoke-filled home Saturday morning to pull an unconscious woman through a window and down a ladder to safety, according to fire officials.

Despite their rescue efforts under difficult search conditions, Carol McCarthy, 73, was later pronounced dead at Leonard Morse Hospital, the state fire marshal’s office said.

“It was just outstanding work on their part. Unfortunately, the end result wasn’t what we were hoping for,’’ said Natick Deputy Fire Chief Daniel Dow, at the scene of the deadly fire at 211 East Central St.

A Natick firefighter on his way to work at 7:38 a.m. Saturday saw low-lying, brownish-yellow smoke creeping across the roadway and called the fire in to the station.

Because of the smoke’s color, Lieutenant Eric Williamson, a nine-year veteran, said he knew it wasn’t emanating from a fireplace or wood stove.

After reporting the fire, Williamson ran around the house and banged on the doors and windows, he said. He picked up a brick and smashed a window, then reached in to unlock a door before going inside.

The lieutenant searched the first floor of the residence,he said in an interview later at the fire station, but found no one. Because the smoke spilling from the second floor was so intense and he had no safety equipment, Williamson could not go upstairs, he said.

By that time, firefighters had arrived.

“He actually did a great thing by calling it in and letting us know what we had, so that when we responded we knew exactly what was happening,’’ said Dow. “We knew what we were walking into.’’

A neighbor who was feeding her dogs just after 7 a.m. said she could see the smoke from her backyard.

Karen, who didn’t want to give her last name, said officials were “banging hard’’ on the back door of the residence.

“The dogs were barking, and that’s when I went out there and saw the smoke,’’ she said.

Amanda Maguschak, who lives across the street, said she and her husband were home when fire crews arrived, and the road was “full of ambulances and firefighter trucks.’’

“You could see smoke from where we were,’’ she said, standing on her front porch.

Maguschak said her husband sometimes saw Mc- Carthy when they were out walking their dogs and Mc- Carthy would say hello, though the couple didn’t know their neighbor well.

Maguschak said the woman was “very polite.’’

A man who identified himself as a close friend of Mc- Carthy’s son, who was on the scene talking to fire officials, described McCarthy as “a good woman.’’ Calls to her family were not returned Saturday. A woman at McCarthy’s son’s home in Natick declined to comment.

A preliminary report indicated that the house had no working smoke alarms, according to the state fire marshal’s office.

The cause of the fire is still under investigation, Dow said, but he did not “characterize it as suspicious.’’

The investigation is being handled by the Natick fire and police departments, State Police assigned to the state fire marshal’s office, and the Middlesex district attorney’s office.

This was the state’s 12th death in a fire so far this year, according to Jennifer Mieth, spokeswoman for the state Department of Fire Services.

Standing inside the lobby of the fire department’s headquarters Saturday afternoon, Williamson said he wished he had his equipment handy when he arrived at the scene.

“I don’t like the outcome. Obviously it’s sad,’’ Williamson said. “If I had my gear, maybe I could have done something. But I didn’t. So I did what I could.’’

Globe correspondent Martha Schick contributed to this report. Steve Annear can be reached at steve.annear @globe.com. Follow him on Twitter @steveannear.