The crash on I-24 in Coffee County of a tanker carrying hazardous materials clogged traffic between Chattanooga and Nashville on Thursday.
The latest estimated time to clear the accident is 5:40 p.m., officials said at mid-afternoon.
The crash at mile marker 97 was reported at 6:40 a.m.
Eastbound traffic is affected with all lanes blocked. Westbound traffic is affected with all lanes blocked. Both directions of traffic are being diverted to alternate routes.
A car was involved in the crash with the tanker, which was carrying five different chemicals. Officials said one is highly flammable and another is explosive.
The Tennesseee Highway Patrol was keeping a 400-foot isolation zone around the incident.
The trucking company was sending another tanker to off-load the chemicals, but the vehicle was having difficulty reaching the scene.