HARRISON — Investigators say oily rags combusting in the heat were the likely cause of a blaze that destroyed a home Thursday afternoon on Ruby Lane.

Shortly after 4 p.m., fire crews were called to 25 Ruby Lane for a report that the single-family home was on fire.

The first arriving crews quickly called for backup from other departments. By 5 p.m., firefighters from various towns including Bridgton, Naples, Sweden, Otisfield, Oxford and Waterford were assisting at the scene.

Within minutes of the initial call, a third alarm had been sounded. Although early reports were that fire crews were contending with exploding fireworks, Harrison Fire Chief Dana Laplante said they faced no such problem.

Nobody was hurt in the fire. By 5 p.m., crews from additional departments, including Sebago, Stoneham and Baldwin were joining the firefighting effort. The fire was declared knocked down soon after, although fire crews were expected to remain at the scene into the evening.

The home sits at the dead end of Ruby Lane, which is off Chapman Road, which runs off Edes Falls Road.

The home was considered a complete loss, Laplante said. It was not immediately clear if anyone was home when the fire started.