KITTERY, Maine (CBS) – A fire on a nuclear submarine dry-docked in Maine is now out, officials announced Thursday morning.

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All seven firefighters injured while fighting the flames are now at home with their families.

The fire originally broke out in the front of the USS Miami while people were on board Wednesday night. The submarine is in its third month in dry dock at Portsmouth Naval Shipyard as part of a 20-month maintenance period.

The nuclear reactor on board was apparently not in jeopardy during the fire. Rear Admiral Richard Breckenridge said the reactor has been shut down for months and it remained stable.

The fire was relegated to four compartments, including the torpedo room. No weapons were on board, however.

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“The fire spread into spaces in the submarine that were difficult to access. The heat and smoke contained in these confined spaces made it challenging for firefighters to combat the blaze,” said Rear Adm. Breckenridge.

According to Navy officials, everyone is safe because of quick work from multiple agencies.

“I want to emphasize the heroic actions of the firefighting teams averted what could have been a much more severe situation. As a result of their quick and effective response, the fire was contained and brought under control,” said Rear Adm. Breckenridge.

Operations are back to normal at Portsmouth Naval Shipyard.

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Officials had no estimates on the amount of damage on the submarine. A full investigation is being conducted to determine the cause of the fire.