CONCORD, N.C. -- Fox Sports says on Monday it still had not determined why an overhead TV camera cable snapped during the Coca-Cola 600.
The network says a full investigation is under way and use of the camera is suspended indefinitely. Earlier, NASCAR said it would wait for Fox Sports to conclude its review before deciding if such technology would be used in the future.
Charlotte Motor Speedway said 10 people were injured when part of the drive rope landed in the grandstand; three were taken to hospitals. All were checked out and released soon after.
Several drivers, including then-leader Kyle Busch, reported damage to their cars from the rope.
NASCAR spokesman Kerry Tharp told The Associated Press on Monday that there were no plans to use the system at upcoming races "so we'll have ample time to review."
The network said the system was provided by Austrian company CAMCAT. The rope that failed was certified for a breaking strength of 9,300 pounds and was only bearing less than 900 pounds of force during the race, according to Fox Sports.
The network said it's reviewing with CAMCAT equipment maintenance records, history and installation information and plans to share its findings with NASCAR and Charlotte Motor Speedway.
The network said the system was used successfully at the Daytona 500 and was set up and working at last week's Sprint All-Star race in Charlotte. Fox's final NASCAR telecast this year comes Sunday at Dover International Speedway.
Tharp said NASCAR would let the network determine what went wrong.
"We'll sync up with them on what they have learned this week and go from there," he said.
The network explained how the drive rope moves the camera back and forth and failed near its turn one connection. The camera, it said in a statement, did not come down "because the guide ropes acted as designed."
The rope, Fox said, was made of Dyneema, which it described as "an ultra-strong synthetic that has the same approximate strength of a steel wire with the same diameter." It said the rope was less than a year old, had been factory-tested by its manufacturer and its breaking strength was certified before shipment. The rope was also inspected by CAMCAT when it was received last June.
According to OnlineRopes.com, Dyneema has the "highest strength-to-weight ratio of any manmade material in the world. On weight-to-weight base, it is up to 15 times stronger than steel."
The pictures such cameras provide can be extraordinary. But in this case, the failure brought confusion and chaos to the racers and the fans.
Coca-Cola 600 winner Kevin Harvick thought he was imagining things when he noticed the black rope on the track. He was among the lucky ones who escaped without damage. Busch said he heard a "thunk" when he ran over it and knew he'd have problems.
Busch used a cellphone to take a picture of the mangled metal around his front, right-side wheel so his team could figure out how to repair the damage.
NASCAR red-flagged the race for about 30 minutes and allowed teams back to their pits to get their cars back to race trim.
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 several problems to the right front wheel well. After completing repairs, the crew slapped high-fives as the car rolled 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. He said the engine problem was not related the rope damage. He thanked NASCAR for how it handled the unique stoppage.
"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.
Ambrose wound up ninth behind Harvick, the second top-10 finish of the year for the Richard Petty Motorsports team.
Kasey Kahne led 156 laps, most of the night, and was second to Harvick. He was as bewildered as everyone else with the TV cable across the track.
"I've never seen anything like it," he said. "I came around turn four, saw it wrapped around Kyle's car, hit mine. I thought I was seeing things."
The camera hung in place over the large painted logo on the grass between the start-finish line and pit road.
Fox broadcaster Chris Myers apologized during the telecast several times to fans, drivers and race teams for the disruption. The network's statement offered "a sincere 'thank you' to the staff at CMS for attending to the injuries and keep us informed on this developing situation."
Busch wasn't sure anybody had seen that happen before and offered a solution: "Maybe now we can rid of that thing."