Eight people in the waiting room of a medical clinic were hurt Wednesday afternoon after a disoriented 91-year-old man hit the gas in his car instead of the brake, sending the vehicle over a curb from the parking lot and into the building, authorities said.

Four people in the lobby were critically injured and taken to a Greenville hospital, Anderson Emergency Medical Services spokesman Scott Stoller said. Six others, including the driver of the car and his wife, had less severe injuries and were taken to a hospital.

None of the injuries appeared life-threatening, Williamston Police Chief Richard Inman said.

The driver apparently had some kind of medical problem as he arrived at the clinic for an appointment and was trying to park his Chevrolet Cavalier, Inman said.

"When I spoke to the driver, he was very disoriented," the police chief said. "He's 91 years old. He didn't know he had been in an accident. He didn't know where he was at that time."

The investigation continues, but if doctors decide the driver was suffering from a medical condition, charges likely won't be filed, Inman said.

Doctors and nurses in the clinic immediately started tending to the injured until paramedics arrived about four minutes later, authorities said.

The doctors at the clinic, which is owned by AnMed Health, will continue seeing patients at the company's other centers until repairs can be made, AnMed spokeswoman Heidi Charalambous said.

The car was removed from the building in less than an hour, leaving behind a gaping hole, crime tape and several investigators milling around.

The car struck the clinic with such force that it ended up entirely inside the building, Stoller said.

"It ended up all the way inside," Stoller said. "If there was a garage door there, you could close it right behind it."