The ride, called the Yo-Yo, collapsed shortly after 6 p.m. Friday at the fair, which features the famous Jumping Frog Jubilee. The event is held just outside the Gold Rush-era town of Angels Camp in the Sierra Nevada foothills.

Associated Press This 1999 file photo shows the carnival ride, called the Yo-Yo, similar to the one that collapsed shortly after 6 p.m. Friday injuring all 24 people aboard at the Calaveras County Fair and Jumping Frog Jubilee, about 80 miles southeast of Sacramento. Video A spinning carnival ride collapsed at a fair near Sacramento, California, last night, injuring all 24 people on board. Most of the riders were children. Media Player The FREE Windows Media Player is necessary to play Windows Media.

Three were airlifted to hospitals in Modesto and Sacramento, but the extent of the injuries was not immediately known, said Sgt. Dave Seawell, a spokesman for the Calaveras County Sheriff's Department.

Most of the riders were children, and all suffered some form of injury, he said.

The fair remained open after the accident, but the carnival area had been shut down, said Laurie Giannini, the fairground's marketing director. She said there were no fatalities and that riders with minor injuries had been treated.

The ride has metal arms, each with a seat at the end attached by a chain, that swing outward as the ride picks up speed. The arms rise and fall as they spin around a center pole, putting the seats horizontal to the ground.

The pole apparently collapsed, causing the arms to crash back toward the center, said Dennis Townsend, a chief in the Calaveras County unit of the California Department of Forestry and Fire Prevention.

“The mechanism that lifts the people is the one that collapsed,” he said.

The riders were hurt when their seats struck the ground or other parts of the machine, he said.

“I was buying cotton candy and the arms collapsed, but it was still spinning,” Cole Sirius, 13, told the Stockton Record.

Another witness told the newspaper she saw the ride operator struggling to stop the machine. Melissa Hall, 17, said she had been at the far all day and thought the ride was functioning poorly in the morning.

“It didn't rise all the way,” she said of the arms.

Authorities could not immediately determine what might have caused the accident.

“We don't know, and nobody at the scene has been able to make a competent determination as to why,” Townsend said.

The three victims who had been airlifted were taken to the University of California, Davis Medical Center in Sacramento, Doctor's Hospital in Modesto and Modesto Memorial North Hospital.

A spokeswoman at UC Davis Medical Center said she could provide no information without a patient's name. Memorial North Hospital would say only that it had received one victim who was in stable condition.

Doctor's Hospital received a female patient with minor injuries, nursing supervisor Robert Norton said.

Gail Witzlsteiner, a spokeswoman for Sonora Regional Medical Center in Sonora, said five teenagers – four girls and a boy ranging in age from 13 to 18 – were treated for minor injuries.

Mark Twain Hospital in San Andreas was caring for five patients, said Jessica Norris, an emergency room clerk. Three arrived by ambulance and two came in on their own. Most complained of knee pain.

The Calaveras County Fair and Jumping Frog Jubilee opened Wednesday and is held each year in late May. It was inspired by a Mark Twain story, “The Celebrated Jumping Frog of Calaveras County,” which focuses on a character and his jumping frog, named Dan'l Webster.

Last year's jumping frog contest drew 4,000 entries. This year's final is scheduled for Sunday.

  

Associated Press Writers Steve Lawrence and Tom Verdin in Sacramento, Calif., contributed to this report.