Mud is flying, smoke and steam are rising, and the deafening roar of V-8 engines all but drowns out 5-year-old Shelby Scott's screams.

"Get out of there! Get out of there!" she yells at the driver of a battered blue Ford LTD spray-painted with the words "Hillbilly Beer Wagon." But car No. 42 stalls in the center of the tire-ringed oval, stranded while 11 others smash into each other, over and over, until only one is moving.

Then Dave Cumpston climbs out of No. 29 through the space where the windshield should be and grabs a shiny trophy at the Valley District Fair Demolition Derby.

It's his first win in six years, he says, and maybe his last: After a decade of building then gleefully crashing cars, the 35-year-old mechanic from Buckhannon is giving up his increasingly unaffordable sport.

Soaring scrap metal prices are making crashable cars more expensive and harder to find. Owners who used to sell their worn-out wheels for $50 to $100 are turning to scrap dealers instead, getting nearly triple the price. That creates a double whammy for drivers like Cumpston, who must burn more high-priced gasoline in an ever-expanding search zone.

"This one sat in a hayfield for six years," says Jamie Wolfe, a tree trimmer from Kingwood who drove No. 42. He bought the body for $100 and considers himself lucky; many drivers are paying $300 to $400 per car.

Demolition derbies are more than an outlet for road rage and a rite of summer in rural America: They're a mainstay of country fairs and a revenue generator for volunteer organizations like the Reedsville Volunteer Fire Company. When participation drops, so does the size of the crowd — and the host's profit margin.

The Midwest is taking an exceptionally hard hit this summer because of regional scrap-metal prices, though Tory Schutte of the Demolition Derby Drivers Association says participation is down nationwide, "easily cut in half."

Every state but Hawaii stages at least one derby a year, and Schutte, of Genoa City, Wis., is accustomed to seeing more than 100 cars at a single event. This year, there are only 40 to 50 as drivers of modest means are forced out.

Aggravating their situation is growing interest by a new breed of participants — doctors, lawyers and other professionals willing to spend more money on the vehicles. Some sink as much as $5,000 into a single engine.

"It's really weeded out the little guy that's building on a limited budget," Schutte says. "He's not going to be able to afford to stay in the sport."

Scrap metal prices are likely to continue to rise, says Bruce Savage, spokesman for the Washington-based Institute of Scrap Recycling Industries, a trade association for more than 1,600 companies. Strong consumption by domestic steel producers is driving up prices, along with demand from developing nations. India, Brazil, China and Korea are among those ravenous for raw materials.

While scrap iron and steel prices vary regionally, Savage says they've easily doubled in the past two summers, from about $240 per ton in July 2006 to $523 per ton now.

In many places, record prices have created a sellers' market.

"I get calls every day asking about the price. If they don't like mine, they go down the road and call the next guy," says Dave Smith, a 15-year employee of Elkins Iron & Metal Co., a scrap dealer in central West Virginia. "It's all about price."

This week, Smith is paying about $320 for a 2-ton vehicle, but he says prices are always fluctuating.

Although more money is changing hands at the Charles Caracciolo Steel Yard in Altoona, Pa., employee Lori Bagley said no one is getting rich. Caracciolo is paying car owners $120 per ton, compared with about $60 per ton two years ago. But the scrap dealer's costs are rising, too, so the profit margin is not widening.

"For a while, more people brought in cars, but the regulations are tough," Bagley said, and many people don't want to go through the hassle of finding the title, removing the tires and draining all the fluids.

Back in Reedsville, a scrap dealer waits outside the pit, offering $240 per ton for cars whose derby days are over.

Former driver Hazel Curtis, mother of the screaming 5-year-old, worries what the soaring costs will do to a sport she describes as "road rage, controlled." She intends to enjoy it as long as she can, even if that means traveling farther to catch an event.

"I just like to see the cars crashing ... the excitement of who's gonna stop and have to sit there and wait, whether they're gonna get squished or not," says Curtis, 43, of Kingwood. "It's just such a rush."

Drivers know why the spectators show up, Schutte says.

"They watch NASCAR and wait for the wrecks," he says. "We just cut right to the chase."

There are rules, and referees to enforce them: No body parts outside the vehicle. No hitting a stalled car without giving it a chance to restart. No hits to the driver's side door.

Still, Schutte says derbies let people act out their primal urges.

"It's kill or be killed, and you destroy him or he destroys you," he says, "but nobody has to get hurt."