CAMP PENDLETON -- A fiery crash on Interstate 5 before dawn Thursday ignited 60,000 pounds of meat, cheese and plastic jugs into a highway barbecue, said California Highway Patrol Officer James Crowe.

The crash occurred just after 5 a.m. on southbound I-5 near Las Pulgas Road, about seven miles north of downtown Oceanside, Crowe said.

A Vons grocery truck broadsided a Mazda van that was idled due to an earlier crash, setting both vehicles on fire, plus all the perishable food in the truck's 53-foot trailer, and sparking a small roadside brush fire, Crowe said.

Thousands of commuters were left stranded for hours in stop-and-go traffic as California Department of Transportation crews worked to clean up the oily, metallic-gray sludge left over by the inferno in the highway's three right lanes.

"It was crazy and some people were frustrated," said 50-year-old Hassan Kany. He left Dana Point at 8 a.m. and didn't get to Oceanside until 1 p.m., a 22-mile journey that turned into a five-hour endurance challenge.

In the slog, he saw four or five cars run out of gas and watched a semitrailer and a tour bus overheat.

The backed-up traffic stretched at least 20 miles to Capistrano Beach in Orange County throughout the morning and into the early afternoon, said Officer Eric Newbury. The highway was closed to all but one of the four lanes all morning, then another lane was opened after noon, he said. All lanes were open by 3 p.m.

Just before the second crash, the Mazda van ran into the back of another semitrailer in the outside lane and the driver was trying to push the van onto the shoulder, Crowe said.

The Vons truck approached in the darkness, apparently not seeing the parked van, which was without lights, Crowe said. The van's driver saw the truck coming and sprinted onto the ridge beside the highway just before impact, Crowe said.

The truck slammed into the van's driver's-side door, setting the van ablaze and hurtling it onto the roadside ridge, which sparked a grass fire, Crowe said. The Vons truck toppled over on its left side before also erupting in flames, turning the meat, cheese and plastic wrappers into an inferno that covered the three right lanes of traffic.

"It smelled like rubber and barbecued chicken," said 27-year-old Trevor Casey of Oceanside. "It was not so appetizing."

An aspiring California Highway Patrol officer, Casey was on his first ride-along with Crowe Thursday morning when the call came. He saw the Vons driver taken by helicopter to Scripps Memorial Hospital in La Jolla with chest trauma. He was conscious and expected to be treated and released Thursday, Newbury said.

The van's driver, while not seriously injured, "seemed like he was definitely frozen after what he went through," Casey said.

Highway Patrol officers were asking for the public's help in finding the other semitrailer involved in the first crash. They knew only that it was white, had an enclosed trailer and probably had damage to its back end, Crowe said.

The driver could be charged with a hit-and-run if he or she knew about the crash and left the scene, he said. However, he said the driver may not have even felt the impact and could have driven off unaware.

The Vons truck had been filled with refrigerated supplies for delivery to three stores in San Diego County, said the company's transportation supervisor, Tony Prieto. It had left El Monte, about 75 miles northeast of the crash site, earlier Thursday morning.

It had two 150-gallon tanks of diesel fuel, said Caltrans maintenance supervisor Susan Reilly, which is believed to have sparked the blaze.

Meanwhile, many commuters talked of feeling helpless as the hours passed and meetings and appointments were missed.

"It was frustrating because there was nothing we could do about it," said Jeff Dransfeldt, 24. A recent college journalism graduate, he had just gotten a call for a dream freelance assignment with the Boston Globe to cover an event at 11 a.m. at the Comic-Con convention in downtown San Diego.

He left Camarillo at 5 a.m., expecting to make it to the convention by 8 a.m. He finally arrived just before noon.

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