CORONA (CBSLA) — A fiery big rig crash on the westbound 91 Freeway through Corona made a soggy morning commute even worse.

A semi was reported on fire at about 4:45 a.m. right at the border of Orange and Riverside counties on the westbound 91 Freeway. All westbound lanes were blocked at Green River Road for a short time immediately after the crash.

Firefighters called out to put out the truck fire said that its load of some sort of hazardous material was either burning or had leaked, prompting a call for hazmat crews.

Several lanes were reopened to traffic about a half hour after the crash, but the damage was done – traffic was backed up for several miles beyond the 15 Freeway.