KITTERY, Maine — A fire on a $900 million nuclear submarine stationed at the Portsmouth Naval Shipyard caused injuries to six people and was still burning early this morning.

KITTERY, Maine — A fire on a $900 million nuclear submarine stationed at the Portsmouth Naval Shipyard caused injuries to six people and was still burning early this morning.



The cause of the fire in the nuclear-powered USS Miami attack submarine remained unknown as of an 11:30 p.m. news conference, said Capt. Bryant Fuller, commander of the shipyard.



"While the fire is not out, the situation is improving," Fuller said.



Shipyard firefighters were first called to the dry docks at 5:41 p.m. The fire started in the forward compartment, which Fuller said consists of primarily living quarters and command and control spaces. All nonessential personnel were ordered to evacuate, officials said.



Just after 10 p.m., the fire aboard the submarine, docked at Dry Dock 2, went to four alarms and fire dispatchers were describing the fire as "moderate."

Fuller said that the ship's reactor was not operating at the time of the fire and remained in a safe and stable condition throughout the event. There were no weapons aboard, he said. Kittery Police Chief Paul Callaghan said the shipyard made no requests for police to evacuate residents in the area and there was no danger to the community.



According to Fuller, there were six reported injuries, including one firefighter who suffered from heat exhaustion. "He is conscious and alert," Fuller said.



The shipyard commander said that due to the heat created from the fire, steam linked to the firefighting effort was emitting from the vessel.



All personnel were accounted for and those who were injured were either treated at the scene or taken to the hospital. Ambulances from multiple Seacoast fire departments arrived and departed from the shipyard throughout the night.



"We have received firefighter assistance from numerous Seacoast communities and we appreciate the tremendous support," Fuller said.

Responding agencies included an engine and foam trailer from Logan International Airport in Boston, Mass. According to the Boston Sparks Association, a fire buff club founded in 1938, an engine from the submarine base in Groton, Conn., was also responding. Apparatus from Hanscom Air Force Base in Massachusetts arrived shortly after 11 p.m.



Residents in some parts of Kittery reported a smell of burning plastic in the air, and sirens from fire apparatus were heard throughout the night.



Smoke and steam continued to billow from the shipyard early into today and was visible from areas such as Peirce Island in Portsmouth, N.H., and the Piscataqua River Bridge. Peirce Island attracted many people eager to get a view of the fire until police officers shut it down to the public, citing safety concerns.



The shipyard gates remained open late Wednesday night, and Fuller said workers should prepare to report to their jobs as normal in the morning. More information will be released as it becomes available, he said.



"A full investigation will be conducted," he said, noting that local, state and federal officials were notified and that Maine and New Hampshire officials were in the shipyard command center.

The USS Miami (SSN 755) and its crew of 13 officers and 120 enlisted personnel arrived at the Navy Yard on March 1 to undergo maintenance work and system upgrades.



It is the third vessel named for the city of Miami and the fifth "improved" Los Angeles-class nuclear-powered submarine, according to the Navy. The Miami was commissioned June 30, 1990, and its home port is Groton, Conn.



The submarine's commanding officer is Cmdr. Roger E. Meyer, who assumed command Sept. 20, 2010. The Miami's host community is Sanford.



According to U.S. Navy specifications, the ship weighs in at 7,102 tons submerged, is 360 feet long and can travel up to 32 knots while submerged. The Electric Boat Division of General Dynamics Corporation in Groton, Conn., built the submarine, which was first launched Nov. 12, 1988. The single-propeller ship features a single nuclear reactor propulsion system. It carries an armament of Tomahawk missiles and Harpoon missiles and has the capacity to lay mines.



Tom Clancy's non-fiction book, "Submarine: A guided tour inside a nuclear warship," published in 1993, was based on the USS Miami.