A 20-year-old man was listed in critical condition after he was struck by a roller coaster at Six Flags Magic Mountain Saturday in Valencia.

The man lost his hat on a ride and climbed two security fences to retrieve it, park officials said. That's when he was struck by the Ninja roller coaster and knocked unconscious.

He remained hospitalized Wednesday. No other details were provided about his injuries.

The roller coaster, which reaches speeds of 55 mph, was shut down until state inspectors determine whether the accident was related to the ride.

The man's name has not been released.

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