(CBS)-- The Navy is investigating a fire aboard one of its nuclear attack submarines.
The USS Miami was docked in a Maine shipyard when the fire broke out.
Seven people suffered minor injuries, but all were back home Thursday morning, reports Bree Sison of CBS Boston station WBZ-TV.
The sub's nuclear reactor wasn't impacted, Rear Adm. Richard Breckenridge, commander of Submarine Group Two, told reporters Thursday.
The sub has been in dry dock at the Portsmouth Naval Shipyard on an island in Kittery, a town near Portsmouth, N.H., while it was being worked on.
Fire broke out in the front of that sub while people were on board Wednesday evening.
Apparently, the nuclear reactor wasn't in jeopardy during the fire. Breckenridge says it's been shut down for months and remains stable.
There were no weapons on board. But the fire did impact the torpedo room, so had weapons been on board, it could have been an entirely different situation.
Tight spaces that burned were a real hazard for emergency crews.
"The fire spread to spaces within the submarine that were difficult to access," Breckenridge said. "The heat and smoke contained in these confined spaces made it challenging for firefighters to combat the blaze. I want to emphasize the heroic actions of the fire fighting teams averted what could have been a much more severe situation."
Operations were back to normal at the shipyard Thursday.