— Five people were taken to WakeMed hospital in Raleigh Thursday night after an accident involving the Vortex ride on the lower midway at the North Carolina State Fair.

Wake County Sheriff Donnie Harrison told reporters at a news briefing late Thursday night that preliminary information he received indicates at least two people suffered critical injuries. Two people were released from WakeMed early Friday.

Information about the three people who remained in the hospital wasn't immediately available.

The victims, Harrison said, ranged from ages 14 to 39 and included a ride operator. He added that some of the victims appeared to be a family, although he could not say what their relationships were.

About 35 to 40 people, he said, were being interviewed in an effort to get a better idea of what happened.

"The ride had stopped, and they were fixing to offload when the ride started off again, but that is preliminary," Harrison said. "It is going to take quite a while to talk to all these people."

Neither Harrison nor Dolores Quesenberry, a spokeswoman for the North Carolina Department of Labor, which inspects the fair rides, would comment about what caused the accident.

"It could be operator error. We don't know," Harrison said. "We aren't going to speculate."

The State Fair will be open on Friday, officials said, but the Vortex will remain closed. Officials will hold a news conference Friday morning to update the public on their investigation.

Harrison also asked that anyone who was in the area and perhaps caught the accident on video to contact the sheriff's office.

"We would like to look at it, because it may help us down the road," he said.

Crime scene investigators were at the scene, and Quesenberry said that when they were done, ride inspectors would begin their work looking at every piece of the Vortex – operated by Powers Great American Midways – to try to find out what went wrong.

Quesenberry said that rides are inspected three times a day and that would be part of the investigation.

"This has shaken us all a bit, and we definitely have these folks in our thoughts and prayers tonight," said Brian Long, a spokesman for the North Carolina Department of Agriculture & Consumer Services.

Long said a sheriff's deputy reported at 9:17 p.m. a person being injured on the lower midway beind the Expo Center and that "almost immediately, the number of injured that were reported rose."

Emergency workers were at the scene within minutes and by 9:37 p.m., all five of the injured had been transported to WakeMed.

"Everybody will have this on their mind. I know the ride inspectors will do their due diligence to make sure everything is going," Harrison said. "As sad as it is, we want people to come out here and have fun. It will be safe."

According to a description of the ride, the main arm is hydraulically lifted to a 30-degree angle and the V-shaped center of the ride starts rotating while car arms on each side spin, twirl and flip passengers upside down. Long said this particular Vortex has not previously been at the fair.

Witnesses told WRAL News that everything appeared normal and then, all of a sudden, they saw a rush of emergency personnel and fairgoers frantically converging to the area.

Lottie Meadows saw the aftermath.

"We saw everyone turn around running," she said. "We looked over, and there were a couple people lying on the ground, on the platform of the ride."

Some weren't moving and one appeared to be under a portion of the ride, she said.

Thursday night's accident isn't the first involving rides at the NC State Fair.

In 2002, a midway worker was thrown from a platform of a ride and killed when he was struck by the legs of a passenger on the ride.

In 1998, three people were injured when a wheel-bearing seized on a roller coaster causing a rear-end collision between three cars.