PORTLAND – The Navy overlooked $16 million in environmental cleanup costs in its analysis of what it would take to close the Brunswick Naval Air Station.

The report by government auditors calls into question whether the costs at other bases were underreported as well, said Sen. Susan Collins, R-Maine.

The Pentagon is closing 22 major bases and scaling back 33 others to save a projected $4.2 billion a year. But it needs another $950 million for environmental cleanups at bases picked for closure in 2005, according to a Government Accountability Office report.

Brunswick was one of four bases studied in the report. The Pentagon originally estimated $147 million in one-time costs to close the Brunswick base.

Congress is debating allocating less money than President Bush has proposed to clean up bases. But Brunswick officials say there’s no cause for immediate alarm because the base closing costs will be spread out over several years.

Carol Warren, chairwoman of the Brunswick Local Redevelopment Authority’s environmental committee, said she would not be surprised if the environmental cleanup costs exceed the $16 million figure.

She said it is hard to predict exact costs because the cleanup is ongoing, with more assessments still to be done.

“I am satisfied the Navy will move forward with the cleanup,” she said, “but my concern is the timing. It might take longer than the public expects.”

Additional costs eat into anticipated savings from closing bases.

Collins, a member of the Armed Services Committee, noted that the same thing happened with the earlier closing of Loring Air Force Base in Limestone.

“This is why, when the Pentagon comes before us claiming huge savings from base closures and realignments, I’m always so skeptical,” Collins said. “Inevitably, the savings turn out to be far less than estimated and the costs turn out to be far greater.”

The Brunswick community is still exploring what to do with the property.

The Navy is expected to set aside 51 acres for the Army National Guard and 11 acres for the Coast Guard. The base’s air traffic control tower will go to the Federal Aviation Administration.