A woman died after a fire in an apartment building early Sunday in southwest suburban Justice.

Firefighters responded at 3:31 a.m. to the blaze in the three-story, six-unit apartment building in the 8300 block of West 83rd Street in Justice, said Roberts Park Fire Protection District Battalion Chief Walter Sherman.

Irma Mercado, 71, was found in her third-floor unit and taken to Christ Medical Center in Oak Lawn, where she died at 4:23 a.m., according to Sherman and the Cook County medical examiner’s office. An autopsy Monday found she died of thermal injuries and inhalation of products of combustion, and her death was ruled an accident.

The woman’s dog was also thought to have perished in the blaze, but the remains have not yet been found, Sherman said.

The fire was extinguished in about ten minutes, Sherman said. The rest of the residents were able to evacuate the building, and no other injuries were reported.

The building is uninhabitable, Sherman said. The cause of the fire is under investigation, but is not thought to be suspicious.