Fairfax County’s Board of Supervisors said Tuesday that, despite a damning federal report on the Pentagon’s decision to relocate thousands of workers to an Alexandria complex, the county would not take legal action — for now.

The board, emerging from closed session, said the report by the Defense Department’s inspector general confirmed what local officials had been saying: The Pentagon’s plans to relocated 6,400 workers to the Mark Center complex off Interstate 395 made no sense because of the impact the move would have on traffic and the area around the building.

But Supervisor Jeff C. McKay (D-Lee) said that although the report confirmed local officials’ longstanding warnings, the board should not head to court just yet.

“Fairfax County has reviewed the matter, and while we remain concerned about the significant traffic impact expected from that new facility, we have determined that federal law does not give the county an opportunity to challenge that environmental assessment at this time,”  McKay said. “We will continue to explore all of our options both legally and legislatively with our federal legislative delegation.”

The inspector general’s report, made available Wednesday, said the U.S. Army Corps of Engineers used faulty data in preparing a 2008 assessment of the environmental impact of the move — a finding that some said could support legal action. Rep. James P. Moran (D-Va.) urged local officials to seek an injunction in U.S. District Court to block the move, which is scheduled for September.