A St. John's woman was treated for smoke inhalation Sunday afternoon, after crews tackling one fire in her home discovered there was also a second.

The dangerous coincidence was discovered soon after the woman called for help as smoke was engulfing her home on Mayor Avenue.

Firefighters discovered smoke coming from a malfunctioning fireplace.

Mayor Avenue fire

Firefighters called to a house on Mayor Avenue in St. John's dealt with not one, but two fires on Sunday afternoon. (CBC)

After fixing the problem, however, they found an unrelated electrical fire in the basement.

"It seems like it's two different incidents at the same time," Supt. Robert Fowler said.

"Initially, the fire started and the problem was with the fireplace but upon further investigation, it seems like there was an electrical problem downstairs — and there actually was a fire downstairs near the electrical box."

Fowler said the second fire could have developed into a more serious blaze if it had not been discovered.

The woman, 55, was alone in the house at the time.