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

As emergency workers tended to injured fans and ambulance sirens wailed in the background, a somber Tony Stewart skipped the traditional post-race victory celebration. The crash began as the field closed in on the finish line and sent rookie Kyle Larson’s car sailing into the fence that separates the track from the seats.

Large chunks of Larson’s car landed in the grandstands. The car itself had its entire front end sheared off, with the burning engine wedged through a gaping hole in the fence.

Volusia County spokesman Dave Byron said six people with serious injuries were taken by ambulance to Halifax Health Medical Center in Daytona Beach.

“Those six met the condition of trauma patients,” Byron said, adding one person was taken to Memorial Health in Ormond Beach, and one person was taken to Halifax in Port Orange. Those two were “not serious injuries.”

Byron said the speedway has its own fire rescue, and the county was only involved in the transport of those eight people.

Neither NASCAR nor Daytona International Speedway officials had any immediate details on injuries in the accident in the race held the day before the season-opening Daytona 500.

“There obviously was some intrusion into the fence and fortunately with the way the event’s equipped up, there were plenty of emergency workers ready to go and they all jumped in on it pretty quickly,” NASCAR President Mike Helton said. “Right now, it’s just a function of determining what all damage is done. They’re moving folks, as we’ve seen, to care centers and take some folks over to Halifax Medical.”

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

“The important thing is what going on on the frontstretch right now,” said Stewart, the three-time NASCAR champion. “We’ve always known, and since racing started, 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.

“So as much as we want to celebrate right now and as much as this is a big deal to us, I’m more worried about the drivers and the fans that are in the stands right now because that was … I could see it all in my mirror, and it didn’t look good from where I was at.”

The accident spread into the upper deck and emergency crews treated fans on both levels. There were five stretchers that appeared to be carrying fans out, and a helicopter flew overhead. A forklift was used to pluck Larson’s engine out of the fence, and there appeared to be a tire in the stands.

Daytona President Joie Chitwood waited by steps as emergency workers attended to those in the stands. Across the track, fans pressed against a fence and used binoculars trying to watch. Wrecked cars and busted parts were strewn across the garage.

“It’s a violent wreck. Just seeing the carnage on the racetrack, it’s truly unbelievable,” driver Justin Allgaier said.

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 local 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.

“I tried to throw a block, it’s Daytona, you want to go for the win here,” Smith said. “I don’t know how you can play it any different other than concede second place, and I wasn’t willing to do that today. Our job is to put them in position to win, and it was, and it didn’t work out.”

As the cars began wrecking all around Smith and Keselowski, Stewart slid through for the win, but Larson plowed into Keselowski and his car was sent airborne into the stands. When Larson’s car came to a stop, it was missing its entire front end. The 20-year-old, who made his Daytona debut this week, stood apparently stunned, hands on his hips, several feet away from his car, before finally making the mandatory trip to the care center.

He later said his first thought was with the fans.

“I hope all the fans are OK and all the drivers are all right,” Larson said. “I took a couple big hits there and saw my engine was gone. Just hope everybody’s all right.”

He said he was along for the ride in the last-lap accident.

“I was getting pushed from behind, I felt like, and by the time my spotter said lift or go low, it was too late,” Larson said. “I was in the wreck and then felt like it was slowing down and I looked like I could see the ground. Had some flames come in the cockpit, but luckily I was all right and could get out of the car quick.”

It appeared fans were lined right along the fence when Larson’s car sailed up and into it.

Keselowski watched a replay of the final accident, but said his first thoughts were with the fans. As for the accident, he agreed he tried to make a winning move and Smith tried to block.

“He felt like that’s what he had to do, and that’s his right. The chaos comes with it,” Keselowski said. “I made the move and he blocked it, and the two of us got together and started the chain events that caused that wreck. First and foremost, just want to make sure everyone in the stands is OK and we’re thinking about them.”

Keselowski said the incident could cast a pall on Sunday’s Daytona 500.

“I think until we know exactly the statuses of everyone involved, it’s hard to lock yourself into the 500,” Keselowski said. “Hopefully, we’ll know soon and hopefully everyone’s OK. And if that’s the case, we’ll staring focusing on Sunday.”