Twenty-eight race fans were injured Saturday when a crash sent Kyle Larson's car airborne and debris flew into the stands at the end of the NASCAR stock car Nationwide Series season-opener.
Joie Chitwood, president of Daytona International Speedway, said 14 injured fans had been transported from the circuit for treatment at local hospitals and 14 more were treated at the track's medical facility.
He said he could not confirm reports that at least two people were seriously hurt and that one was taken immediately for surgery.
"It's not appropriate for me to comment on that," Chitwood said.
The wreck, which occurred almost as Tony Stewart was taking the chequered flag for victory, began when Regan Smith turned sideways and a dozen cars bunched behind him.
"My fault," admitted Smith. "I threw a block."
Larson, making his first start in NASCAR's second-tier series, was launched into the catch-fencing.
Larson's car tore a hole in the fence separating the track from the stands. His engine sheared off with at least one tire and other debris flying into the grandstand.
"I looked in the mirror and that's the worst image I've ever seen in a race in my life," Stewart said.
A fan who identified himself only as "Tyler" sent amateur video to ESPN and spoke with the sports network about the frightening scene.
"I saw a tire about 10 feet from me, just a row above me with a man under it and people yelling for help," he said in a telephone interview.
"Our prayers and thoughts are with everybody they are working on," NASCAR President Mike Helton said of those being treated by emergency medical personnel.
None of the drivers involved in the crash was injured, but driver Michael Annett was hospitalized with chest bruising after hitting a safety barrier in an earlier crash in the race.
"We've always known since racing started this is a dangerous sport," a subdued Stewart said. "As much as we want to celebrate, I'm more concerned about the fans and the drivers right now."
Chitwood said speedway and NASCAR officials responded appropriately and according to their safety protocols, with emergency personnel in place and able to begin work promptly.
Steve O'Donnell, NASCAR's senior vice president for racing operations, said the entire incident would be reviewed to see what, if any, changes could be made to improve safety.
Until then he declined to speculate on what went wrong or right.
"We need to take the time to really study it and see what we can improve on," O'Donnell said.
The race came on the eve of the season-opening event in NASCAR's top-flight Sprint Cup series, the Daytona 500.
Both O'Donnell and Chitwood said they expected Sunday's race to start on schedule.
"We expect to go racing tomorrow with no changes," Chitwood said.
Danica Patrick will start the Daytona 500 from pole position after becoming the first woman to top qualifying for a NASCAR race.
Patrick had also picked up a ride for Saturday's race, driving for Turner Scott Motorsports. She suffered engine failure early on and wasn't involved in the late-race chaos.