Two San Diego County men died when the Porsche they were racing crashed and caught fire Thursday morning at California Speedway in Fontana, authorities said.

Benjamin Miles Keaton, 39, and his passenger, Corey Nicholas Rudl, 34, both of La Jolla, died from injuries after Keaton lost control of a 2005 Porsche Carrera GT.

The car left the track, careened onto a grassy area and struck a barrier. The engine compartment then caught fire, according to a San Bernardino County sheriff's report.

On-site medical personnel, the same used for NASCAR and Indy Racing League events at the speedway, responded at 10:40 a.m. and quickly extinguished the fire, sheriff's officials said.

Rudl, who worked in Internet marketing, was pronounced dead at the scene; Keaton was airlifted to Loma Linda University Hospital, where he died about an hour later, according to the San Bernardino County Coroner's Office.

Both suffered multiple traumatic injuries, but neither suffered burns, said Supervising Deputy Coroner Randy Emon. The vehicle made a passenger-side impact at more than 100 mph. Both men were wearing helmets and safety belts, authorities said.

"The driver's side was in good shape, but the passenger side was obliterated," Emon said.

The accident occurred while the track was being rented by the San Diego chapter of the Ferrari Owners Club. Such events are common at the speedway; the facility is in use nearly 300 days a year for a variety of events, including track days by auto clubs and driving schools.

The men are the fourth and fifth fatalities at California Speedway since it opened in 1997.

Champ Car driver Greg Moore was killed during a race in 1999, and Ricky Lundgren died during competition at an AMA Superbike event in 2003. Another motorcyclist died during a track rental in September.