Pennsylvania State Police say the accident happened just before 1 a.m. Friday morning near Exit 14.
Troopers say the tractor trailer hit a guard rail and then rolled over onto the interstate, sprawling across all of the southbound lanes.
Franklin County dispatch said all southbound lanes of I-81 between exits 10 and 14 were closed Friday morning. Southbound traffic was detoured off the highway at exit 14 and onto State Route 316. Drivers were able to re-enter I-81 from State Route 914, also known as exit 10.
The driver of the truck sustained minor injuries in the accident.
The truck was carrying hazardous materials, so HAZMAT was also called to the scene to clean-up.
Interstate-81 southbound reopened around 10:30 a.m. Friday.
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