BELMONT — No one was injured in a structure fire in Belmont on Saturday evening, but responding firefighters happened upon an antique, rocket-propelled grenade launcher.

Firefighters got the alarm for a fire at 38 Champagne Ave. at 5:41 p.m., after receiving reports of smoke coming from the building, and arrived on scene at 5:46 p.m., according to a fire department press release.

The first firefighters to arrive observed heavy smoke coming from under the eaves of a two-story detached garage at the end of a cul-de-sac. Firefighters laid 1,000 feet of hose and utilized a rural hitch to fight the fire, while primary and secondary searches were underway. A rural hitch is a device that allows firefighters to attach a truck’s hose to access water from another truck, after the first truck’s water supply is depleted, for example.

Upon entry, firefighters discovered fire and water damage on the first floor, and smoke damage to the second. The cause of the fire is under investigation, but it’s believed to be an electrical fire originating from the area of an outlet where an air compressor was plugged in, Chief Deborah Black said Monday morning.

Firefighters honed in on wires burned off the top of the air compressor which led into a nearby outlet, and suspect that’s the cause and point of origin of the fire.

There were no injuries in the fire, but responding firefighters did find the RPG and two rounds of ammunition inside the building. One round was loaded into the launcher’s tube and another was resting atop a counter next to the probable point of origin of the fire.

“I walked in and I looked, and I’m like, ‘Is that a bazooka?’” Black said.

Belmont Police were called to the scene to determine if the weapon could be rendered safe, and concluded the launcher and one of the rounds of ammunition were already deactivated, but could not determine if the second round was live or dead. The State Police Explosive Disposal Unit was contacted to evaluate that round.

State Police determined one round was likely live and needed to be disposed of, and firefighters and police from Belmont assisted them with its safe removal.

To own such replicas is not a crime, and Black said there weren’t any charges filed in the ordeal.

“They are legal,” she said. “You can buy them at antique places and stuff.”

The scene was under control by 6:40 p.m., and cleared at 9 p.m.

Firefighters from Laconia, Gilford, Tilton-Northfield and Gilmanton assisted Belmont at the scene. The Franklin Fire Department covered Belmont during its response. Sanbornton firefighters assisted with a medical incident while Belmont was tied up at the fire.

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