CORONA -

A tanker truck that overturned and exploded today on the eastbound Riverside (91) Freeway near the Corona (71) Expressway was involved in a chain-reaction crash that resulted in no serious injuries, authorities said.

The crash involving the gas truck, another big rig and four compact vehicles occurred around 10:30 a.m., according to the California Highway Patrol.

CHP Officer Maurice Walker told KCAL9 the crash was triggered when a big rig on the eastbound 91 swerved to avoid hitting a car, causing the tanker truck to swerve out of control and hit another vehicle and a Honda Accord.

"That vehicle was launched over the center median into westbound lanes and came down in westbound lanes, where it was struck by a Volkswagen Jetta," Walker said.

The tanker ended up a crumpled heap, its 8,800-gallon haul erupting in flames that raged for nearly three hours.

The driver managed to escape the fire, and none of the other motorists were seriously hurt, according to Walker.

The driver of the Accord, identified as a Fountain Valley woman, was transported to a hospital for treatment of what were described as non-life- threatening injuries.

"We were lucky there weren't any more vehicles or injuries or fatalities," the officer said.

Corona, Riverside and Riverside County fire crews raced to contain the conflagration, which forced the closure of all of the eastbound and westbound lanes on the 91 at the outset of the busy Memorial Day holiday weekend.

Eastbound 91 traffic was being diverted into Corona at Green River Road, causing a massive traffic jam.

The westbound side of the freeway reopened at 2:35 p.m., along with the southbound 71, which had been closed to traffic beginning at Euclid Avenue in Chino Hills.

Caltrans spokeswoman Terri Kasinga told Channel 9 that the eastbound 91 would remain shut for "several hours" while crews cleared debris and assessed damage to the pavement.

"We'll move as quickly as possible to make repairs, even temporary repairs, to open this up to holiday traffic," Kasinga said.

She said alternate routes into the Inland Empire, including the Pomona (60) Freeway and Interstate 10, were clogged, and even after the eastbound 91 is opened, the effects of the closure will be felt well into the night.

"Coming home to the I-E is going to be a nightmare," Kasinga said.