If the Washington area were hit by a chemical or biological attack, Fairfax County students would be kept in locked-down schools, inaccessible to parents, while teachers helped undress and shower any who needed decontamination, according to a plan adopted by school authorities.

In a throwback to the "duck-and-cover" exercises of the 1950s and '60s, schools will begin drills -- minus the shower scenario -- as early as this fall to prepare for potential attacks, Fairfax school security officials said.

While the county is the first in the Washington region to develop school procedures for dealing with chemical attacks, the U.S. Department of Education plans to recommend this spring that school systems across the nation do likewise, federal officials said.

After the terrorist attacks of Sept. 11, 2001, "that's what it has come to," said James McLain, security coordinator for Fairfax schools. "We have the federal government telling us that terrorist attacks are not a matter of if, but of when."

Recalling the drills that sought to prepare students for nuclear war decades ago, McLain remembered climbing under desks and seeing radiation symbols in elementary schools.

"We really are going back to a preparedness level that we used to be at," he said.

School administrators have begun briefing parents about the new procedures, and many parents said they would rather have the plan in place than be caught unprepared. Still, the idea of being separated from their children was unsettling to some.

"You know on a conscious level that that's the right thing to do. But when the time comes and you can't see your child, it's going to be tough on a lot of parents," said Diane Brody, president of the Fairfax County Council of PTAs, adding that she thinks children will understand.

"I think kids are so resilient," she said. "Unless they were not in school at all during 9/11, they've been through something, and I think they would be able to comprehend that it's for their own good."

While the thought of teachers undressing and showering students was uncomfortable to Robert Walters of the Alexandria area of Fairfax, the father of two students said he would support the school effort.

"It's not the school system's fault that we have to make these plans. It's the world situation that's putting this on us," he said.

Fairfax's security plan is of a type known as "Shelter in Place," and it is predicated on the notion that in a chemical attack, people are often safest if they remain inside. Such plans have been put in place by some school districts and local governments near nuclear plants, armories and chemical factories.

Almost two years ago, for instance, when a freight train carrying hazardous chemicals derailed and caught fire in a Baltimore tunnel, authorities ordered a nearby assisted-living home to shelter-in-place until residents could safely evacuate the area.

If a similar accident or a biological attack occurred in Fairfax County, schools would follow rigorous procedures. Staff members would shut all vents and seal doors and windows with duct tape and wet towels to keep out contaminated air. Students who happened to be outside when the chemicals were released would be showered and then would change into gym clothes or a second set of emergency clothes kept by the school. The rest of the children would be sent to a safe room, McLain said.

The plan is designed to keep students safe for several hours until hazardous substances are carried off by the wind, said Mark Scott, president of the National Institute for Chemical Studies in Charleston, W.Va., a nonprofit group that has been promoting the program.

Even though contaminated air eventually will seep into buildings, Shelter in Place has proved effective, he said.

Scott had a firsthand look at the program in 1999 when a factory in Charleston began to leak dangerous chemicals. On an adjacent field, high school students were playing football. Administrators immediately implemented the program, using the gymnasium as a shelter. No one was hurt.

Other school districts said they would take a look at the Fairfax plan. In Montgomery County, administrators are discussing the Shelter-in-Place concept, said Edward A. Clarke, director of school safety and security.

This spring, the U.S. Department of Education plans to recommend the Shelter-in-Place concept for school systems across the country, said William Modzeleski, director of the safe and drug-free schools program.

Referring to the repeated warnings by federal officials of possible terrorist attacks, Modzeleski said, "I know that a lot of schools have focused in on school shooters, but we now know that's not the only thing that we have to plan for."