DAYTONA BEACH (Reuters) - NASCAR officials ran the Daytona 500 as scheduled on Sunday, saying there were confident of spectator safety after Saturday's crash that injured more than 30 fans and raised the possibility of lawsuits.

The race began at 1 p.m. EST and in typical fashion, the always incident-packed Daytona 500 saw an early collision on lap 33 with nine cars involved.

No one was injured when several cars spun off the track, including one of the favorites, Tony Stewart, and 2007 Daytona 500 winner Kevin Harvick.

Workers had repaired the fencing that was damaged in Saturday's pile-up, which sent debris flying into the crowd and injured spectators on the final lap of the second-tier Nationwide race.

Two spectators initially listed as critical were in stable condition on Sunday, and others were either in stable condition or had been treated and released.

Fans streamed into the 167,000-capacity venue on Sunday and there was little indication of concern over safety.

"I feel safe. I think anywhere you go you run the risk of being injured but NASCAR does everything they can to protect the fans. They treat the fans like royalty here; it is amazing," said Vinny Nigro of New York City.

Another fan, Brad Stefka from Springfield, Missouri, said he was not particularly worried but would avoid the seating closest to the track.

"Everyone who comes knows there is some element of danger," Stefka said.

Daytona International Speedway president Joei Chitwood offered to relocate any fans in the affected area and attempt to relocate any fan uncomfortable over seating location.

NASCAR's Senior Vice President of Racing Operations Steve O'Donnell said fan safety was the first priority .

"We are confident in what's in place at today's event. Certainly still thinking about those affected but we are confident to move forward for this race," O'Donnell said.

POTENTIAL LITIGATION

NASCAR and the speedway could face millions of dollars worth of claims from the injured, litigation that would likely center on the sturdiness of the safety fence that was supposed to keep fans from danger, according to several plaintiffs' lawyers.

"Maybe the fence should have been higher; maybe there should have been more spacing between the track and spectators," said Adam Levitt, a lawyer with Grant & Eisenhofer.

However, lawyers also said the auto-racing business would likely point to the disclaimers typically displayed on tickets, which are designed to exempt NASCAR from any potential injury liability. They expected NASCAR would argue fans knew what they were getting into when signing up for the race.

International Speedway Corporation, which owns and manages NASCAR racetracks, has rarely defended itself in public lawsuits against NASCAR fans over personal injury claims arising from accidents at its racetracks.

Recent accidents at NASCAR racetracks include last year's lightning strike at Pocono Raceway, which killed one fan and injured nine others, and a 2009 crash at Talladega Superspeedway when a car hit the catch fence and an 18-year-old suffered a broken jaw from a piece of car.

No lawsuit could be found in International Speedway Corporation's filings with the U.S. Securities and Exchange Commission (SEC) that were related to either instance, nor was there record any personal injury claim online.

NASCAR requires tracks to have $50 million in insurance to cover spectator injuries, a policy that would likely cover any lawsuits filed, according to Jeffrey Reiff a personal injury plaintiffs' lawyer.

INJURY TOLL

Twelve spectators were taken to Halifax Health with five of them released as of Sunday, the hospital said. All of the remaining patients had stabilized, the hospital said. Another six patients taken to a sister hospital were treated and released.

Another injured spectator was being treated at Florida Hospital Memorial Medical Center in Daytona Beach, but a condition update was unavailable.

Fourteen other fans had been treated on site at the track on Saturday, Chitwood said.

Both the speedway and NASCAR have said they will closely review the incident in search of any ways they could improve safety.

Three-time Indianapolis 500 winner Johnny Rutherford said a change might be needed.

"Maybe a double fence, one behind the other with some space in between to stop something like this," he told reporters. "But there are a lot of things and NASCAR and Indy Car racing are looking at everything they can to make it safer."