A vacuum cleaner was identified Wednesday as the source of the fire that caused about $400 million worth of damage last month to a nuclear-powered submarine at the Portsmouth Naval Shipyard.

Meanwhile, members of Maine’s congressional delegation said the Navy has indicated to them that the Los Angeles-class USS Miami likely will be repaired, and that the repairs will be done at the shipyard in Kittery.

Preliminary findings by the Navy indicate the fire that started on May 23 aboard the USS Miami started in a vacuum cleaner, said Deb White, spokeswoman for the Portsmouth Naval Shipyard.

The vacuum cleaner — whose make and size were not disclosed — was used to clean worksites on the sub after shipyard workers’ shifts, White said. The machine was unplugged at the time of the fire and stored in an unoccupied space.

White said details about how the fire started remain under investigation.

The submarine was about two months into a 20-month overhaul at the shipyard when the fire broke out in its forward compartments and burned for about 10 hours.

U.S. Sen. Olympia Snowe, R-Maine, a senior member of the Senate Intelligence Committee, said she was told Wednesday by the Navy that the USS Miami “can be repaired” for about $400 million.

The final decision on whether to make the repairs and salvage the sub will be made by the end of next week, Snowe said.

She said she is optimistic that the Navy will decide to repair the sub rather than replace it with a new Virginia-class submarine, which would cost about $2.4 billion.

If the Miami is fixed, the repairs likely will be made in Kittery. Should the Navy decide to build a new vessel, it would be built at a shipyard outside Maine, said Brandon Bouchard, Snowe’s spokesman.

“As Vice Admiral McCoy indicated to me while I toured Kittery-Portsmouth Naval Shipyard after the fire, the U.S. Navy intends to rebuild the USS Miami, and I agree that is precisely what the Navy should do,” Snowe said in a prepared statement.

Rep. Chellie Pingree, D-Maine, a member of the House Armed Services Committee, responded to Wednesday’s announcement by saying she is confident that the submarine will be repaired at the Portsmouth Naval Shipyard.

“Chellie hasn’t spoken to anyone who doesn’t think the sub can be repaired,” said Willy Ritch, her spokesman.

Pingree is married to S. Donald Sussman, majority share owner of the Portland Press Herald/Maine Sunday Telegram.

Sen. Susan Collins, R-Maine, a member of the Senate Armed Services Committee, said in a statement issued Wednesday night: “It is welcome news that the Navy appears committed to repairing the USS Miami at the Portsmouth Naval Shipyard.”

The fire heavily damaged the forward compartment of the submarine, including the crew’s living quarters, command and control spaces and the torpedo room. No torpedoes or other weapons were on board at the time.

White, the shipyard’s spokeswoman, said the Miami’s nuclear propulsion spaces were not affected. The vessel’s nuclear propulsion plant had been shut down for the overhaul.

In Wednesday’s announcement, White indicated that it will cost the Navy an additional $40 million — over the $400 million estimate — if it chooses to repair the Miami.

The additional costs represent the impact of repairing the Miami on the construction and repair schedule across all naval shipyards. White said the Navy may have to contract out some work to the private sector.

White said $400 million is still a rough repair estimate because Navy engineers are doing a full technical assessment, including internal and external surveys of the hull.

That assessment is expected to be completed next week.

“While the Navy’s rough estimate to repair the submarine is $400 million, we won’t know an exact figure until the assessment is completed,” Collins said. “As a member of both the Senate Armed Services Committee and the Senate Appropriations Defense Subcommittee, I will work to help identify the funding that will be needed.”

Staff Writer Dennis Hoey can be contacted at 791-6365 or at:

dhoey@pressherald.com