LOUISVILLE, Ky. -- Six Flags and Cedar Fair shut down eight more thrill rides around North America on Friday after a teenage girl's feet were sliced off during a ride in Kentucky.

State inspectors were at the Six Flags Kentucky Kingdom to examine the Superman Tower of Power, where the accident happened Thursday. The ride lifts passengers 177 feet, then drops them nearly the same distance at speeds reaching 54 mph.

It was unclear at what point in the ride the 13-year-old was injured, said Wendy Goldberg, a Six Flags spokeswoman. The girl was taken to a hospital, where her condition was not immediately available Friday.

Six Flags shut down similar rides at parks in St. Louis; Gurnee, Ill.; and near Washington as a precaution, Goldberg said. She said Six Flags Over Texas, near Dallas, also has a Superman Tower of Power, but it is not the same ride.

There had been no reports of injuries on the ride before Thursday, she said.

"Millions of people have safely ridden this ride in our parks," Goldberg said.

Cedar Fair Entertainment Co. also shut down drop tower rides at five of its amusement parks for inspection, company spokeswoman Stacy Frole said. Frole described it as a precautionary measure.

Intamin AG, a Swiss company, made all the rides but did not supply all the parts, said Sandor Kernacs, president of the company's American operations, Intamin Ltd. in Glen Burnie, Md.

Bill Clary, a spokesman for the Kentucky Department of Agriculture, which inspects amusement park rides, said a cause hadn't been determined Friday afternoon.

The accident didn't appear to slow business Friday at Six Flags Kentucky Kingdom. A stream of cars and foot traffic poured into the amusement park on a warm, breezy summer day.

The five Cedar Fair rides that were shut down are at Kings Island near Cincinnati; Canada's Wonderland, in Toronto; Kings Dominion in Doswell, Va.; Carowinds, in Charlotte, N.C.; and Great America in Santa Clara, Calif.