One person was killed after a big rig rolled over, spilling its load of lumber onto Highway 299 Tuesday. The crash happened just before 5:30PM in the construction zone near Buckhorn Summit. The California Highway Patrol says the big rig was traveling east coming down the hill when it tipped over onto its side. The driver, a 51-year old man from Larkspur, Colorado complained of back pain and was taken to Mercy Medical Center for treatment. His passenger, a 44-year-old woman from Sutherland, Oregon was also taken to Mercy where she succumbed to her inuries . According to the CHP, neither was wearing a seat belt, and their identities have not been released.