Six lawmakers who oversee homeland security issues called Monday for an investigation into whether federal agencies share research on technology for preventing nuclear materials from being smuggled into the United States.

At issue is research by at least five national laboratories that develop systems for detecting hidden nuclear materials illegally brought into the country.

The labs are funded by four federal departments — Homeland Security, Defense, State and Energy — that deploy nuclear detection systems in the United States or abroad. But lawmakers worried that poor information-sharing among the agencies could lead to duplication in the labs.

"It is unclear what advantages we achieve by having so many laboratories involved in these disparate research efforts," said the lawmakers in a letter dated Monday to Government Accountability Office Comptroller David M. Walker.

The GAO is Congress' investigative arm.

The lawmakers also questioned whether a new Domestic Nuclear Detection Office (search), as proposed in the Homeland Security Department's budget for next year, would be hindered by such duplication. But Homeland Security spokeswoman Kathleen Montgomery said the office was being created, in part, to prevent those problems.

The new office "will strengthen the department's oversight of the deployment and use of radiation detection equipment, provide greater focus to our work with national laboratories and improve our national response to a potential nuclear threat," Montgomery said.

Results from the GAO investigation are expected within four months. The six lawmakers who ordered the probe include Sens. Susan Collins, R-Maine, chairman of the Homeland Security and Governmental Affairs Committee, and Carl Levin of Michigan, the top Democrat on the Armed Services Committee. Also seeking the investigation are Republican Sen. Norm Coleman, R-Minn., and Rep. John Linder of Georgia; as well as Democratic Reps. John Dingell of Michigan and James Langevin of Rhode Island. All sit on congressional committees that oversee nuclear issues.