HILLIARD, Fla. -- Two Nassau County firefighters were injured on Wednesday fighting a house fire near Hilliard.

Channel 4 was told the four firefighters were inside the garage of the burning home in the 22000 block of Fortress Lane when the roof caved in, injuring two of them.

"The roof collapsed, pinning one of the firefighters to the ground," Nassau County Fire Chief Chuck Cooper said.

Lt. Patrick Cauley was flown to Shands-Jacksonville Medical Center with burns to his arms and hands. He was treated and released. A second firefighter who rushed in to rescue Cauley was treated at the scene, then returned to the firefighting effort.

"They put a lot of heroic effort into getting that fireman out," Cooper said.

About 30 Nassau County firefighters were used to put out the blaze, and one unit remained at the scene six hours later checking on hot spots.

Jacksonville Fire-Rescue sent three engines to the scene to assist and made six other units available to cover Nassau County fire stations while those firefighters were in Hilliard.

A 9-year-old boy first spotted the fire and got his grandfather out safety, then they called 911.

The house was a total loss. The state fire marshal's office was on the scene investigating the cause of the fire.