Tony Stewart surged late and won Saturday’s Drive4COPD 300 Nationwide Series race at Daytona International Speedway as the 120-lap event ended with a spectacular crash near the start-finish line.

As the field swept out of the fourth turn, chaos erupted at the front of the pack as leaders Regan Smith and Brad Keselowski crashed. As victory contenders slid and spun along the frontstretch, the Chevrolet of rookie phenom Kyle Larson sailed into the grandstand fence, hitting a support post. The entire front clip of Larson’s car was sheared away, and a portion of the engine went through the fence and landed on a spectator concourse. The engine was on fire briefly. A tire sailed high into the grandstand, and car parts also flew into the seating areas.

Medical personnel responded to the accident scene and appeared to be treating fans in two sections of the grandstands. There was no immediate indication how many might be injured or how seriously, although several were removed from the main grandstand on stretchers.

“Hopefully, all the fans and drivers are OK,” Larson said. “I was getting pushed from behind. By the time my spotter said, ‘Lift,’ it was too late. I had some flames come in the cockpit. Luckily, I was all right and could get out of the car quickly.”

The shell of Larson’s car landed on its wheels past the start-finish line. He was able to climb out of the car seconds after the wreck. Several other cars were heavily damaged. NASCAR later said 12 cars were involved in the accident. Among those involved were Dale Earnhardt Jr., Travis Pastrana, Elliott Sadler and Justin Allgaier.

The finish order listed Stewart in front of Sam Hornish Jr., Alex Bowman, Earnhardt Jr. and Parker Kligerman.

Ceremonies in victory lane were subdued as participants waited to hear from the accident scene.

“The important thing is what’s going on on the frontstretch right now,” Stewart said. “We’ve always known since racing was started this is a dangerous sport. We assume that risk. It’s hard when the fans get caught up in it. I could see it in the mirror, and it didn’t look good.”

None of the drivers involved in the last-lap crash was injured.

The accident appeared to start with contact between Smith and Keselowski, who were gunning toward the first line in a tight tandem draft.

The wild finish was set up with five laps to go after a major, multi-car accident in the first turn. The crash began when Michael Annett made contact with Austin Dillon, sending Dillon and Annett into the outside wall. A big pack of cars followed, and many became involved in the wreck.

Annett was transported to nearby Halifax Medical Center for evaluation and was reported to be aware and alert.

With fluids and parts trashing the track, NASCAR put the field under a red flag for cleanup.

Pole winner Trevor Bayne took his Ford to the garage on lap 85 with apparent transmission issues. He was running fourth.

The third caution of the race flew on lap 65 after contact between Mike Wallace and Annett started a melee as the field exited the fourth turn.

Wallace’s car shot across the track and onto the apron grass, and he was followed by Reed Sorenson, Joe Nemechek and Kurt Busch.

Regan Smith spun in the trioval after contact with Elliott Sadler on lap 32. Juan Carlos Blum was also involved in the accident. Smith recovered quickly, and, in fact, later led the race.

Scott Lagasse Jr. produced the afternoon’s first caution, spinning in the trioval on lap 9.

Danica Patrick left the race after only 31 laps when the engine in her Chevrolet soured.

Mike Hembree is NASCAR Editor for SPEED.com and has been covering motorsports for 31 years. He is a six-time winner of the National Motorsports Press Association Writer of the Year Award.