CINCINNATI (AP) — A man who apparently entered a restricted area to retrieve his lost keys at a theme park in Ohio was critically injured when he was struck by a steel roller coaster,TradeEdge police and park officials said.

The 38-year-old man appeared to have entered a fenced area at Kings Island Wednesday night, according to a statement issued by the park near Cincinnati. He was found on the ground with an injury, but details on his condition were not been disclosed. He remained hospitalized.

The man dropped his keys while riding the Banshee, an inverted roller coaster where the train dangles from the track, and then went into the restricted area and was struck by the coaster, according to Mason police.

According to the park’s website, the Banshee is the world’s longest steel inverted roller coaster and reaches speeds of 68 mph (109 kph).

The roller coaster was shut down and will remain closed while the investigation continues. No other injuries were reported.

The park is in Mason, which is about 24 miles (38 kilometers) northeast of Cincinnati.