An 81-year-old Harbor Gateway man died in a fire believed to have been caused by a heater inside the home early Sunday morning, fire officials said.

Firefighters responded to the blaze around 6:34 a.m. to find heavy smoke and fire showing from the single-story home in the 500 block of 157th Street, Los Angeles Fire Department officials said.

Neighbors were trying to get to the man who was trapped inside by the flames. His daughter was also trying to rescue her father, and she sustained burns that were not life-threatening, according to the department.

Firefighters searched for the man as others began aggressively attacking the flames.

The crew quickly extinguished the blaze about 20 minutes later, eventually finding the man who was pronounced dead at the scene.

“The cause of the fire was determined to be the accidental use of an outdoor heating element of propane being used to heat the home inside,” LAFD spokesman David Ortiz told KTLA.

Arson investigators determined the fire to be accidental, finding that the family was using a heater that was not designed to be used indoors in the bedroom, where the man was found, LAFD Spokeswoman Margaret Stewart said.

After the tragic fire, officials urged residents to be cautious when using any portable heating device, and only use indoor heaters that have a safety certification mark on them inside homes. The heaters should never be left unattended or while all occupants are sleeping.  

“We like to remind folks that we’re getting colder weather here in Southern California, it’d be a good time to check with the gas company, make sure your furnaces and proper-use heating elements are being used inside the homes,” Ortiz said.