SOUTH PORTLAND — Fire officials have determined that the cause of a blaze that nearly destroyed a Cape-style house on Calais Street on Tuesday morning was electrical and accidental.

The fire at 12 Calais St. started shortly before 7 a.m. and was contained to the second floor, said Capt. Robb Couture, spokesman for the South Portland Fire Department. However, there was significant smoke and water damage to the first floor, leaving the single-family home uninhabitable.

Couture said he couldn’t provide more specific information about the cause of the fire, which was extinguished within a couple hours.

Two occupants of the home discovered the fire before smoke alarms went off and safely evacuated with their two dogs.