Update 8 am:
Tennessee Highway Patrol has reopened all southbound lanes in Anderson County following semi fire near the Norris exit at mile marker 121.
(WBIR) A tractor trailer fire has shut down I-75 southbound in Anderson County.
The Tennessee Highway patrol says all southbound lanes near the Norris exit at mile marker 121 will be closed until about 8 a.m. as crews extinguish the fire in the semi. Troopers are diverting southbound traffic to alternate routes.
A trooper said no cargo was on-board the semi, and no one was hurt in the crash.