The heat from the fire was intense enough to melt part of the highway. ((CBC))

A tanker truck explosion and fire led to the collapse of an overpass on a freeway leading to San Francisco's Bay Bridge early Sunday.

The truck was hauling32,500 litres of gasoline when it crashed into a pylon on the interchange that connects Oakland with San Francisco.

The heat from the resulting firemelted part of the highway's upper deck, causing it to collapse on to the road below, officials said.

Television footage showed flames rising from the destroyed tanker beneath the concrete rubble.

The driver walked away from the scene withsecond-degree burns and took ataxi to a nearby hospital, an officer withthe California Highway Patrol said.

No one else was hurt.

Transportation officials said it could take several weeks, if not months, to repair the highway.

With files from the Associated Press