MERCED — A two-alarm fire gutted part of a Merced home Thursday morning, sending three people to the hospital, according to Merced Fire Department Chief Mike McLaughlin.

The blaze was reported at 10:50 a.m. at a one-story home at 733 Robinson Drive. Fire officials said the blaze started in an attached apartment unit behind the home.

Four fire engines responded to the blaze, which was knocked down in about 15 minutes, McLaughlin said.

After an investigation, officials have ruled the fire an accident, he added.

McLaughlin said the fire began after a man living inside the apartment dropped a cigarette in his room. The tenant, an unidentified man in his 60s, was using a home oxygen tank, he said.

The combination of the oxygen and cigarette caused the fire to grow rapidly, McLaughlin said.

"Anything hot around upholstery and furniture is always dangerous," he said. "But when you have oxygen, it's that much worse. It took a bad situation and made it worse."

The owner of the home, J.J. Thuener, 31, said the man used oxygen for a variety of health problems. When the fire broke out Thursday morning, Thuener said he heard the man calling his name.

"I saw the flames coming out of his bedroom window and it was so hot," Thuener said. "I went to get a garden hose and had to pull him out."

Three people were taken to the hospital for observation and treatment of smoke inhalation, including the man and a friend who was visiting Thuener's mother. A neighbor also was taken by ambulance to the hospital.

The victims, whose names weren't released because of hospital privacy rules, were listed in stable condition with minor injuries.

The apartment unit is considered a total loss, according to McLaughlin.

Reporter Ramona Giwargis can be reached at (209) 385-2477 or rgiwargis@mercedsunstar.com.