A semi-truck hauling 21,000 pounds of cardboard crashed and spilled its load onto Highway 152 near Gilroy Tuesday afternoon.
The semi-truck crashed at 2:30 p.m. The truck driver told the CHP that he fell asleep at the wheel. When he startled awake, the driver realized he was about to drift off the highway and over-corrected.
Highway 152, also known as Pacheco Pass, was still blocked in all directions at 3:40 p.m.
CHP officers said Highway 152 near Frazer Lake Road would remain for hours.
As the semi flipped, cardboard tumbled out and quickly became soaked in diesel fuel which leaked out of the truck's fuel tank.
No other vehicles were involved in the crash.
The driver was not hurt.