

Pieces of mail (Photo by bikeriderlondon via Shutterstock)

We hope your important mail wasn't in this truck. A big rig containing 120,000 pieces of USPS mail was engulfed in flames on an Orange County freeway early this morning.

The privately-owned big rig was contracted by the USPS to take mail over to Ontario Airport, but it caught on fire around 1:30 a.m. near North Lambert Road on the 57 Freeway in Brea, according to the O.C. Register and CBS Los Angeles. The driver was not injured.

It took firefighters about an hour to quell the fire, reported CBS Los Angeles. Witnesses said the truck looked like it exploded as it was going down the freeway.

A CHP officer told a videographer at the scene that the USPS truck had rear-ended another big rig, reported City News Service. However, the CHP told the O.C. Register they are still investigating the cause of the fire.