DAYTONA BEACH, Fla. - At least 33 NASCAR fans were injured Saturday when large chunks of debris, including a tire, sailed into the grandstands when a car flew into the fence at Daytona International Speedway on a frightening last-lap accident in the second-tier Nationwide Series race.

The crash began as the field closed in on the finish line and sent rookie Kyle Larson's car hurtling into the fence that separates the track from the seats. Large chunks of Larson's car landed in the grandstands. The car's front end was sheared off, with the burning engine wedged through a gaping hole in the fence.

Daytona International Speedway President Joie Chitwood said 14 fans were treated on site, and 14 others were taken to hospitals. Volusia County spokesman Dave Byron said six people with serious injuries were taken to Halifax Health Medical Center in Daytona Beach.

"Those six met the condition of trauma patients," Byron said.

As emergency workers tended to injured fans and ambulance sirens wailed in the background, a somber Tony Stewart skipped the post-race victory celebration.

Stewart, who won for the 19th time at Daytona and the seventh time in the last nine season-opening Nationwide races, was in no mood to celebrate.

"The important thing is what is going on in the frontstretch right now," said Stewart, a three-time NASCAR champion. "We've always known ... this is a dangerous sport. But it's hard. We assume that risk, but it's hard when the fans get caught up in it."

It was a chaotic finish to a race that was stopped nearly 20 minutes five laps from the finish by a 13-car accident that sent driver Michael Annett to a hospital, where his Richard Petty Motorsports team said he would be held overnight with bruising to his chest.

The race resumed with three laps to go, and the final accident occurred with Regan Smith leading as he headed out of the final turn to the checkered flag. He admittedly tried to block Brad Keselowski to preserve the win.

As the cars began wrecking all around Smith and Keselowski, Stewart slid through, but Larson plowed into Keselowski and his car was sent airborne into the stands.

Pit stops

• Ironwood Ridge High grad Alex Bowman, in his first full season with the Nationwide series, finished third behind Stewart and second-place finisher Sam Hornish.

• Daytona Speedway President Joie Chitwood said he was confident the track would be repaired in time for today's Daytona 500. Chitwood said he didn't anticipate moving any fans from seats. The grandstands where fans were injured are about 200 feet from the start-finish line.

In practice Saturday for today's race, Dale Earnhardt topped the speed chart, turning the fast lap by averaging 198.592 mph. David Gilliland was second, followed by Clint Bowyer, Marcos Ambrose and Aric Almirola.

Pole-sitter Danica Patrick and Stewart-Haas Racing teammate Stewart were among 10 drivers who skipped the final tuneup. Patrick is trying to become the first driver win Daytona from the pole since Dale Jarrett in 2000.