(FORTUNE Magazine) – Almost nothing stops all-terrain vehicles, those three- and four-wheeled motorcycles for thrill seekers who like to venture off the beaten track and don't mind disturbing nature to get there. But the U.S. Consumer Product Safety Commission is standing in the way. In late January the commission reportedly asked the Justice Department for clearance to ban small-size all- terrain vehicles, or ATVs, because they have been associated with thousands of injuries and hundreds of deaths. Japanese companies, including Honda, Suzuki, Kawasaki, and Yamaha, own the market for ATVs, and Americans bought about 465,000 of them last year at prices from $669 to $3,499. The vehicles, which are not allowed on roads, are popular among youngsters, who do not need licenses to drive them. Less than 5% of ATVs sold have been children's models -- small three- and four- wheelers that go up to 14 miles per hour, half the top speed of the bigger vehicles. But about 21% of the 644 persons who have died in the past five years have been under 12. ''It's a very serious problem,'' says safety commission member Anne Graham, who graduated from a six-hour course on how to ride ATVs. ''It takes a high degree of skill to operate an ATV, and children under 12 don't have those skills.'' Late last year the CPSC voted to ask companies to voluntarily stop making the smaller vehicles. Manufacturers say that a ban would be a flawed tactic since more than 60% of the children under 12 who were injured on three-wheeled ATVs in 1985 were riding adult models. They say that banning the small versions would likely cause more injuries and deaths, since youngsters would just move up to larger, more dangerous vehicles.