The 12-foot-high "stun-lethal" fences, similar to ones used at some state prisons, can be set to deliver a shock if touched once, and a fatal jolt if touched a second time.

The Federal Bureau of Prisons expects to award contracts for the fences in late fall, spokeswoman Traci Billingsley said. "This new technology will serve as new security and help us to deter potential escapes, allow us to operate more cost-effectively by reducing the guard towers, the staffing at some of our guard towers," she said.

Judy Freyermuth of the Federal Prison Policy Project, a nonprofit prison reform group in suburban Atlanta, predicted the hoped-for savings will never materialize.

"How many times have you read of an escape from a federal prison? None," Freyermuth said.

Mike Allen, president of Crowley Co. in Minneapolis, said he is unaware of any deaths or injuries caused by a lethal or stun-lethal prison fence in the United States. Crowley is part of a team assembling a bid for the federal prison job.

The fences at slated for two prisons in Coleman, Fla., and prisons in Tucson; Terre Haute, Ind.; Hazelton, W.Va.; Pine Knot, Ky.; and Pollock, La.

Arizona has encountered no problems with an 8,000-volt stun-lethal fence it installed at its Florence prison last August, said Tony Zelenak, Corrections Department construction manager.