Fire broke out on Wednesday evening on a U.S. Navy nuclear-powered submarine docked at the Portsmouth Naval Shipyard in Maine, injuring four firefighters, officials said.
The cause of the fire is not yet known, but the vessel's nuclear reactor was not involved. There were no weapons aboard the sub, which is at the shipyard for system upgrades and maintenance.
The fire started in the 'forward compartment' of the U.S.S. Miami, an attack submarine docked at the Kittery, Maine, shipyard shortly before 6 p.m. ET
Firefighters were still battling the blaze after 10 p.m., with equipment brought in from as far away as Boston's Logan International Airport, about 60 miles away.
"The ship's reactor was not operating at the time and was not affected," shipyard spokeswoman Tami Remick said by telephone from Kittery.
All nonessential personnel on the submarine were ordered to evacuate when the blaze was reported.
Local media said black smoke was visible in Portsmouth, New Hampshire. The naval shipyard is located on Seavey Island just over the New Hampshire-Maine border.
The submarine, whose home port is Groton, Connecticut, arrived at the shipyard in March. Miami typically carries a crew of 13 officers and 120 enlisted personnel.