Sumter, S.C. (WLTX)-- Protruding garage doors and heavy smoke greeted Sumter firefighters as they responded to a house fire Tuesday along Kingsbury Drive, off of South Guinyard Drive.

Fire investigators are working to determine what sparked the flames.

Fire officials say the original call came in just after 11:30 a.m. as an explosion. They responded to the home and say they found heavy smoke coming from the residence. Once inside, there was fire in the attic area of the structure.

Captain Joey Duggan with the Sumter Fire Department says there is no confirmation that an explosion took place. However, he did say the garage doors of the structure were protruding outward. Firefighters aren't yet sure what caused that, but are investigating. No one was at home at the time of the fire. Damages are estimated at $60,000.