CMS vice president of communications Scott Cooper said after the race that all three fans were treated and released from the hospital. He said he couldn't discuss the nature of their injuries due to privacy laws.
Cooper said seven other people were treated with minor cuts and scrapes at the track and released.
Fox Sports released a statement Sunday night saying it hasn't determined the cause of the accident and it is suspending use of the camera system indefinitely.
"Our immediate concern is with the injured fans," Fox said in the statement.
Fox said the camera system consists of three ropes — a drive rope that moves the camera back and forth, and two guide ropes on either side. Fox said it was the drive rope that failed near the first-turn connection and fell to the track.
"The camera itself did not come down because guide ropes acted as designed," Fox said in the statement. "A full investigation is planned, and use of the camera is suspended indefinitely."
Fox said it has used the camera system at the Daytona 500, at last week's NASCAR Sprint All-Star race and other major sporting events.
"We certainly regret that the system failure affected tonight's event, we apologize to the racers whose cars were damaged, and our immediate concern is for the race fans," Fox said in the statement. "We also offer a sincere thank you to the staff at CMS for attending to the injuries and keeping us informed on this developing situation."
The incident occurred on lap 121 of the 400-lap NASCAR Sprint Cup race.
The race was delayed for 27 minutes while crews repaired damage to their cars.
Kyle Busch, going for a sweep at Charlotte Motor Speedway after winning the Nationwide and Truck series races, was leading when he incurred damage to the right front wheel well of his No. 18 Toyota.
Marcos Ambrose and Mark Martin also reported damage.
No drivers were injured.
The cars were initially brought along pit row as workers cleared the ropes from the track.
NASCAR first threw a caution flag before two red flags came out. It eventually allowed the cars to come into the pits, giving crews 15 minutes to work on their cars.
During the break, Busch's crew frantically worked to repair a number of problems to the right front wheel well. After completing repairs to the car, the crew slapped high-fives after getting the car back on the track.
Busch remained competitive and was running in the top five at the midpoint of the race. But his night ended in frustration when his engine blew up on lap 253.
"I commend NASCAR for taking the initiative and letting us repair our damaged cars from the issue we had," Busch said.
Busch said he never saw the nylon rope.
"I just heard a big thunk on the right-front side tire and thought the right-front tire blew out," Busch said. "That's how hard it felt... It did have an effect slowing my car down and I could feel it like, 'Whoa, that's weird.' I don't know that anybody has ever seen that. Maybe now we can get rid of that thing."
It was more bad luck for Busch, who has never won a Sprint Cup race at Charlotte Motor Speedway and suffered his share of bad luck.
Kasey Kahne, who wound up finishing second behind Kevin Harvick, said he thought his eyes were playing tricks on him when he saw something strange on the track.
"I have never seen anything like it," Kahne said. "I came off turn four and I saw it wrapped around Kyle's car and it hit mine and I thought I had to be seeing things because there's no way there could be a cable on the race track. By the time we got to turn one I saw it again and saw Kyle's fender and saw his car go down a little. That's when I knew I wasn't seeing things."
NASCAR said the camera system in question is from CamCat.
The CamCat camera system is the product of an Austrian company that does work with many outfits around the world, including the Olympics, NBC and others. The company has been handling sporting events since 2000 and hasn't had any prior known incidents with its cameras.
In May of 2000, more than 100 fans were injured outside of the CMS when an 80-foot section of the walkway fell an estimated 25 feet onto a highway below. Fans were crossing the bridge to a parking lot following the completion of the NASCAR All-Star race.
Copyright 2013 The Associated Press.