SAN FRANCISCO (CBS SF) — A vehicle fire on the Bay Bridge snarled westbound traffic into San Francisco Thursday morning, forcing Caltrans to make emergency repairs that closed lanes for hours.

A utility truck with propane on board was burning just east of Fremont Street at around 8:43 a.m.. At least two explosions were seen engulfing the burning propane tanks.

READ MORE: 'Fire Hose' Of Subtropical Moisture Bearing Down On Bay Area; Flash Flood Watch For North Bay

Emergency crews headed to the fire from San Francisco and San Francisco fireboats shot water onto the blaze from below.

Traffic headed toward San Francisco from Oakland was backed up for miles. As of 9:11 a.m., the two left westbound lanes had been reopened according to the California Highway Patrol.

READ MORE: San Jose Police Department Civilian Employee Faces Weapons Charges, Accused Of Social Media Threats

By 9:40 a.m., fire crews reported they had extinguished the fire. They also opened lane #3 to allow for more traffic to go through.

Responders reported no injuries from the blaze. There was no immediate word on what caused the fire.

While three westbound lanes reopened, the closure of the two right lanes for Caltrans repairs made travel into San Francisco difficult, creating a massive backup leading to the toll plaza.

MORE NEWS: Student Arrested For Threatening Violence At San Bruno's Capuchino High School

All lanes were reopened by Caltrans by around 1:15 p.m. following repairs.