Kyle Larson (32) goes airborne into the catch fence in a multi-car crash including Dale Earnhardt Jr. (88), Parker Kligerman (77), Justin Allgaier (31) and Brian Scott (2) during the final lap of the NASCAR Nationwide Series auto race at Daytona International Speedway Saturday. — AP DAYTONA BEACH, Florida — At least 33 NASCAR fans were injured when a car flew into the fence at Daytona International Speedway Saturday, hurling a tire and large pieces of debris into the stands. The accident happened on the last lap of the second-tier Nationwide Series race on the eve of Sunday's Sprint Cup season-opening Daytona 500, which officials said would go on as scheduled. The crash began as the field approached the checkered flag and leader Regan Smith attempted to block Brad Keselowski to preserve the win. That triggered a chain reaction, and rookie Kyle Larson hit the cars in front of him and his car went airborne into the fence. The entire front end was sheared off Larson's car, and his burning engine wedged through a gaping hole in the fence. Chunks of debris from the car were thrown into the stands, including a tire that cleared the top of the fence and landed midway up the spectator section closest to the track. The 20-year-old Larson stood in shock several yards away from his car as fans in the stands waived frantically for help. Smoke from the burning engine briefly clouded the area, and emergency vehicles descended on the scene. Ambulance sirens could be heard wailing behind the grandstands at a time the race winner would typically be doing celebratory burnouts. "It was freaky. When I looked to my right, the accident happened," said fan Rick Harpster, who had a bird's-eye view of the wreck. "I looked over and I saw a tire fly straight over the fence into the stands, but after that I didn't see anything else. That was the worst thing I have seen, seeing that tire fly into the stands. I knew it was going to be severe." Shannon Speedway President Joie Chitwood said 14 fans were treated on site, while local officials said 19 fans were taken to neighboring hospitals, including two who were in critical condition but were later upgraded to stable. 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. "I tried to throw a block. It's Daytona, you want to go for the win here," Smith said. As the cars began crashing all around Smith and Keselowski, Stewart slid through for the win, but Larson plowed into Keselowski and his car was sent spearing into the fence. Keselowski watched a replay of the final accident, and 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. — AP