A video posted on Twitter shows a tractor trailer fully engulfed in flames on I-77 southbound. The incident happened around 3pm on Monday near MM 50 just north of Mooresville. The fire closed several lanes in the area while crews worked to control the fire and clear the scene. Statesville Fire Department reported one firefighter being treated for heat exhaustion, but says they are expected to be okay. Crews are still working to clear the scene, and say it could be 8pm before the area completely reopens. Drivers are told to expect delays.