On July 22, 1995, at 0130 eastern daylight time, a Cessna 337, N53499, had the propeller strike a passenger who exited the airplane at the Tulip City Airport, Holland, Michigan. The airplane was not damaged. The pilot was not injured and the passenger was seriously injured. The flight was to have originated shortly after the accident occurred. The pilot stated that after performing the engine run-up at the end of the runway, he opened his side window to wipe dew off the windshield. He stated the passenger opened her door and was unable to reach the windshield with her seatbelt on. The pilot reported that the passenger unfastened her seatbelt and stepped out of the airplane. He stated he reached out to stop her but she was already out of his reach. He stated he reached for the fuel flow levers and moved them to idle cut-off. Prior to the propellers stopping the passenger stepped into the rear side of the forward propeller. The propeller contacted her right arm and thigh. The pilot exited the airplane and moved the passenger to a grass area alongside the runway. He then returned to his airplane and taxied back to the ramp area where he called the local authorities for help.