( CNN ) -- Firefighters extinguished a blaze in a nuclear submarine early Thursday at a U.S. Navy shipyard in Maine after battling it for hours , according to a statement released by the shipyard . Seven people were injured and were treated either on the scene or at `` a local medical facility , '' the statement from the Portsmouth Naval Shipyard read . Among those injured were three firefighters from the shipyard , two ship crew members and two civilian firefighters , who assisted the Navy 's fire crew . Vacuum cleaner blamed for fire on nuclear submarine . The USS Miami 's reactor was not operating at any time the fire broke out and remained unaffected and stable throughout , said Capt . Bryant Fuller , commander for the shipyard , which is in Kittery , Maine . The sub was in dock at the shipyard when the blaze began , where it has been `` since early March for an overhaul . '' Firefighters first responded to the fire at 5:41 p.m . ET Wednesday . The fire started in a forward part of the ship away from the reactor , affecting `` primarily living areas and command and control spaces , '' Fuller said . `` The nuclear propulsion spaces were physically isolated early in the event from the forward compartment fire , '' according to the statement . The USS Miami is capable of carrying Tomahawk cruise missiles and Mark 48 torpedoes . No weapons were on board , Fuller said . State , local and federal authorities were notified of the incident . `` The cause of the fire is not known at this time , '' Fuller said . `` A full investigation will be conducted . '' Portsmouth Naval Shipyard was established on June 12 , 1800 , and is the oldest continuously operating shipyard run by the Navy , according to Gary Hildreth , a public affairs officer for the facility . CNN 's Larry Shaughnessy and CNN 's Chris Boyette contributed to this report .
Thursday : Fire on USS Miami at shipyard in Maine was put out early Thursday . Friday : Seven were injured in the submarine blaze . The ship 's reactor was not damaged , and no weapons were aboard , officials said .