The U.S. Forest Service has delayed implementation of a new, more strenuous physical fitness test, which had been designed to determine whether federal firefighters could meet the rigors of battling forest fires.

Forest Service officials suspended the program this summer because of concerns about pretest health screening and administration of the exam. A Forest Service worker in Arkansas died of cardiac arrest earlier this year after collapsing during the test and the agency is reviewing whether the test contributed to the death.

The agency, part of the Agriculture Department, had decided to use the test only on an experimental basis last year. The Interior Department and many state and county fire agencies, however, use the test as a requirement for hire on the fire line.

Researchers developed the Work Capacity Tests (WCT) two years ago to replace the step test that required a fire-line recruit to step up and down from a crate for five minutes while maintaining a certain heart rate.

The WCT requires fire-line recruits to carry a 45-pound pack across a three-mile course in under 45 minutes. To qualify for less strenuous duty at a fire scene, workers can walk shorter distances with less or no weight.

Since some unfit workers with slow heart rates could easily pass the step test, many fire officers welcomed the pack test, saying it would improve safety.

But union representatives feared that the new test might be harmful if taken by people not obviously unfit and that it might discriminate against some individuals, whether by gender, weight or the dimensions of their bodies.

"We always had concerns that sedentary people would try to take the test with no training," said Sheila Dykes, president of the National Federation of Federal Employees Partnership Council.

Harry Croft, assistant director of planning for fire and aviation management at the Forest Service, said the pack test will remain suspended at least until the review of the Arkansas death is completed.

"If the board [reviewing the incident] finds the test contributed to the death, or is flawed, then we are going to have to regroup," Croft said.

Interior's Bureau of Land Management had a death associated with the pack test about a year and a half ago, when an employee died while training to take the exam. "We reviewed the death and determined that it wasn't the WCT that caused it," said Roy Johnson, a BLM employee at the National Interagency Fire Center. "But health screening was a factor. And we felt we could deal with that."

BLM now requires firefighters to fill out a health questionnaire, and fire-line workers must have a physical every three years. Workers who put on weight or appear out of shape can be sent in for a checkup.

Bruce Littledog, a Bureau of Indian Affairs engine foreman on Montana's Blackfeet Reservation, said the pack test has improved the performance of Indian crews because it's encouraged them to exercise and get fit before taking it.

"Only about one out of 10 will flunk," he said. "It's just the same as the [step test]. "Those who flunk just don't have the legs. They weren't in shape to begin with."