The blaze, dubbed the Shell Fire, broke out Sunday afternoon and has burned at least 1,200 acres, according to Cal Fire. It is 2% contained.
The Kern County Fire Department said a car caught fire, sparking the grass fire.
Flames have moved close to a stretch of the freeway at Grapevine Road as firefighters try to stop it from spreading further.
No evacuations have been ordered and no injuries reported.
The cause of the fire is under investigation.
This is a developing story. Stay with us for updates.