Washington

Prominent US senators have charged the Department of Defense with doing too little to halt the brain drain from laboratories that carry out research for the US military.

In a letter to Donald Rumsfeld, the defence secretary, seven members of the powerful Senate Committee on Armed Services, led by Joe Lieberman (Democrat, Connecticut) and James Inhofe (Republican, Oklahoma), expressed frustration with what they see as the Pentagon's tardy efforts to reinvigorate the laboratories, which have been losing talent and prestige for years.

In particular, the senators attacked the Pentagon for failing to exploit special hiring systems, created by Congress, to attract young scientists back to the labs. “We have become increasingly dissatisfied with the systematic underutilization of these provisions,” the 1 August letter complained.

The Pentagon's research system includes the three major service laboratories — for the Army, Air Force and Navy — as well as a number of specialized testing centres, employing a total of nearly 15,000 people. The Naval Research Laboratory based in Washington DC, in particular, was once a renowned centre of international excellence in several disciplines. But since the end of the cold war, the laboratory's workforce has shrunk by about a third, and many of the staff are now nearing retirement, says Vice Admiral Paul Gaffney, who was chief of naval research from 1996 to 2000.

Civil-service hiring rules have hampered efforts to attract new staff, says Lance Davis, an official at the National Academy of Engineering who formerly oversaw the labs from the Pentagon. Lab directors have to post openings for long periods of time and Pentagon officials must sign off each hire — delaying job offers for months, Davis says. “Directors who run billion-dollar laboratories have no control over who they work with,” he adds.

To try to fix matters, Congress has repeatedly legislated to create pilot programmes that allow the Pentagon to streamline hiring and give the labs more salary flexibility. The senators also asked for laboratory directors to be granted authority to hire and fire without the approval of Pentagon bureaucrats. “Congress gave the Department of Defense this ability and they haven't done anything with it,” says one Senate staff member.

Cynthia Colin, a Pentagon spokeswoman, said she could not comment as officials had not had time to review the letter and formulate a response.