The children swarmed onto the new rubber-tire swings, ignoring the drizzle and the wet ground as they moved in wheelchairs and walkers toward the newest equipment at the H.W. Wheatley Early Childhood Center playground.

But the adults gathered for Thursday's dedication in Capitol Heights couldn't stop looking at the wood chips.

Four years of research and about $200,000 went into developing these chips, special wood particles that will mesh to form a rubberlike surface, safe enough for a playground and smooth enough to handle a wheelchair.

As schools across the country work to make their playgrounds comply with the Americans With Disabilities Act, the innovative chips put in place in Prince George's County could provide a model for an affordable and accessible solution.

"This is a big deal because wood chips are very cheap for a playground surface," said Theodore Laufenberg, chief researcher on the project. "A wood-chip surface is about $2,000, compared to a rubber surface, which is about $30,000."

This was such a big deal to Laufenberg that he flew in from the federal Forest Services' Forest Products Laboratory in Wisconsin to be part of the ribbon-cutting. He even brought an official U.S. Department of Agriculture pamphlet he authored, titled "Improving Engineered Wood Fiber Surfaces for Accessible Playgrounds."

"I worked with 20 different binders to tie together wood chips," he explained. "My concept was take a wood chip, to make it look natural and, at the same time, make it stable."

President Bush declared last week National Forest Products Week and, in observance, researchers and educators gathered Thursday to dedicate the model playground at the Wheatley center, where about 10 percent of the 600 children use wheelchairs or walkers.

"For our children, having access is a beautiful thing," said Pamela Hoffler-Riddick, Region III executive director for the county school system. "We are the first school in the Washington area and along the East Coast to have use of a playground like this."

Principal Linda Wiskochil of the Wheatley center was so happy about the playground that she baked gourmet chocolate chip cookies for all of the school's guests. "Having a barrier-free playground allows children in walkers or who have trouble with access to get to equipment they normally couldn't get to."

In addition to the wood-chip surface and the tire swings, the playground will soon have a slide and other equipment designed to let disabled children play alongside their non-disabled peers. On Thursday, the kids in wheelchairs and walkers had the run of the place, as other students watched.

Four-year-old Aaron Harrison rolled over to the new swings and scooted on. "We can swing fast," said Aaron, who along with a group of other children sang songs, presented oversized thank-you cards and cheered the group of scientists there for the dedication.

The federal officials said they were delighted to see their work so appreciated.

"This is one of the best things, to see our research put into a product that someone can use. You live your whole life as a researcher to deliver something," said Ann M. Bartuska, deputy chief of research and development at the Forest Service.

To complete the project, Terry Brown, a maintenance foreman for Prince George's schools, worked with Zeager Bros., a Middletown, Pa., company that supplies wood chips for school playgrounds. The grant for the playground came from the U.S. Access Board, an independent federal agency committed to accessibility for people with disabilities.

Even though it continued to drizzle and most of the officials went inside for cake, Brown lingered for a bit to look at his handiwork.

"My job," he said, "is to try to make a difference every day for these kids."

Calvin Brown, left, and Ryan Ward, both 4, got to abandon their wheelchairs for some serious playground time during the dedication.