At a hearing held by the House Armed Services Committee, lawmakers said a Navy warfare center in Charleston, S.C., being used to install the radio jammers and communications systems on the mine-resistant ambush-protected vehicles, familiarly called MRAPs, is not organized to do the work.

"It kind of reminded me of the middle of the night before Christmas assembling my kids toys," said Rep. Gene Taylor, D-Miss., who recently visited the Charleston facility. "I'm still not convinced we're doing everything we can do."

Even though the 15,274 MRAPs to be built are needed to protect U.S. troops from the common threat of roadside bombs, each branch of the armed services has its own unique gear it wants installed, said Rep. Neil Abercrombie, D-Hawai'i.

As defense contractors build greater numbers of vehicles, this variety of models further slows the integration process in Charleston, Abercrombie said, and creates support problems once the MRAPs are fielded.

John Young, the Defense Department's top acquisition official, defended the decision to use the Charleston facility, which is expected to handle 50 MRAP installations a day by mid-December.

According to Young, much of the gear being put into the MRAPs is very sensitive and requires specialized testing facilities the private-sector manufacturers don't have.

Young said he's pressed hard to make the MRAPs as uniform as possible.

"But at the end of the day I have to respect the senior military leaders' decision that says, 'Certain things have to be unique,'" Young said.

The Marine Corps, for example, insisted on a radio frequency jammer that differs greatly in size, weight and power from those used by the other services.