A fire on U.S. Highway 17 in Red Top Thursday night brought dozens of fire trucks and emergency units to the scene, closing the highway in both directions and backing up southbound traffic for at least a mile.

The fire broke out at Roberts & Sons Signs at 3915 Savannah Highway about 9 p.m. Flames were going through the roof when the first units arrived.

The fire was out in about an hour, although firefighters continued spraying down the building for several hours. The interior of the corrugated metal building was gutted.

Fire trucks from multiple agencies and other emergency units were lined up and down the highway either fighting the fire or standing by.

The building is on the northbound side of the highway, but the southbound lanes were also closed because of massive hoses stretching across the highway.

The St. Andrews Fire Department was assisted by the Charleston Fire Department and the St. Johns Fire Department, as well as Charleston County EMS, the Charleston Police Department, and the Charleston County Sheriff’s Office, St. Andrews Fire Marshal Nathan Murtaugh said in a news release issued this morning.

Firefighters were able to limit the damage to about 30 percent of the building, Murtaugh said. Investigators were on the scene to try to determine the cause and origin of the fire. The investigation was expected to continue throughout the day.

One firefighter was taken to a hospital for heat-related illness, Murtaugh said. That firefighter was treated and released.

Reach Dave Munday at 937-5553 or follow him on twitter @dmunday.