After nearly 11 hours, all lanes of southbound Interstate 5 are now open, following closures Thursday morning.

The California Highway Patrol says fatigue may have played a factor in two big rig crashes on the southbound I-5.

According to the CHP, just around 1:30 a.m., a big rig ran into another big rig south of Lebec Road on the southbound I-5, causing both to go up in flames. 

Crews shut down three lanes for clean up. Lanes have since opened, but cleanup is ongoing. 

A few minutes later, at around 2:15 a.m., another big rig also ran into a semi-truck, also causing a fire. 

One of the big rigs was carrying milk. 

All but one lane have been shut down. Cleanup is expected to last until about noon.