Kids who ride ATVs have an alarming number of potentially disabling injuries, a study reports. All-terrain vehicles, or ATVs, weigh up to 600 pounds and can travel at speeds of 65 mph or more. The study adds to other evidence suggesting dangers faced by children who ride ATVs: The Consumer Product Safety Commission says 40,400 children were treated in U.S. emergency rooms in 2005 after ATV accidents. "The public should know that ATVs are not safe," says researcher Chetan Shah of the Arkansas Children's Hospital in Little Rock, who presented his team's findings Monday at the annual meeting in Chicago of the Radiological Society of North America. Shah and his colleagues studied 500 children and teens injured in ATV accidents and brought to the emergency room at Children's Hospital over eight years. They found that the number of ATV injuries more than doubled from 1998 to 2006. Bone fractures were the most common problem during that time frame: 208 children received such an injury. Shah recalls one 2-year-old who had a broken thighbone: She's 5 now, but she still walks with a limp, he says. Head injuries also were common. The team counted 85 skull fractures, 66 cases of bleeding in the brain and 59 children who had damage to the brain tissue. In some cases, the head injury was mild and the patient recovered, but in other cases, the brain didn't heal completely. "Some kids end up with learning problems," he says. In 12 cases, children were injured so severely in an ATV crash that doctors at the Arkansas hospital had to amputate an arm or a leg. The study said six children died after ATV accidents. Shah says his study included only children who made it to the hospital alive. The American Academy of Pediatrics recommends that children under 16 be barred from ATV use, but the vehicles are largely unregulated and, some doctors say, they're growing in popularity. "Kids see ATVs on TV. They see their friends riding them, and they're very attractive," says Donald Frush, a pediatric radiologist at Duke University in Durham, N.C. Doctors such as Frush say children don't have the judgment or coordination to operate an ATV properly. But Doug Morris, director of the All-Terrain Vehicle Association, a Pickerington, Ohio, group that lobbies for the rights of ATV riders, says, "Hundreds of thousands of kids ride ATVs safely." Parents should supervise children and make sure they're wearing protective gear, says Tim Buche, president of the Specialty Vehicle Institute of America, an Irvine, Calif., group representing the major makers of ATVs. Buche says the vast majority of accidents occur when riders disregard safety precautions outlined by the industry. Enlarge By Vivian Johnson, Erie Times-News, via AP Kids take an ATV safety course from Jim Campbell, center, and Jack Albertson, right, near Venango, Pa. Campbell heads up the Erie chapter of ATV Traction, a non-profit that promotes safe use of ATVs. Conversation guidelines: USA TODAY welcomes your thoughts, stories and information related to this article. Please stay on topic and be respectful of others. Keep the conversation appropriate for interested readers across the map.