BATH — A fire on a destroyer under construction at Bath Iron Works was extinguished without injuries Monday night, a BIW spokesman said.

The fire, which was reported at approximately 7:30 p.m., occurred in an empty storage tank on the DDG-1001, the future USS Michael Monsoor, BIW spokesman Jim DeMartini said from the scene.

Reports of light smoke prompted the evacuation of the 67,000-square-foot Ultra Hall on Washington Street until firefighters determined — using thermal imaging cameras — that the fire was in the storage tank, Bath Fire Chief Stephen Hinds said Monday night.

Firefighters extinguished the “very small” debris fire by carrying portable water cans up flights of stairs on the ship, and then down stairs into the tank, according to Hinds.

“They did a great job,” Hinds said. “It was kind of hot and time-consuming, and strenuous to get down into those spaces with all that gear.”

Firefighters cleared the scene at about 9 p.m., he said.

“It was mostly smoke,” DeMartini said. “There’s not any indication of serious damage.”

BIW will investigate the blaze.