A Tesla big rig that caught fire kept both directions of California’s Interstate 80 closed in the Sierra Nevada for hours on Monday.

Cal Fire crews responded to the scene of an electric semi-truck fire around 3 a.m. near Emigrant Gap. California Highway Patrol later confirmed they were dealing with a hazardous materials situation due to potentially toxic fumes from the big rig’s batteries.

First responders say that the batteries of the electric big rig were still burning hours later.