A car and a truck collided around 4:40 this afternoon, closing Route 7 north of Branchville.
Three people were reported injured, one possibly seriously.
The accident occurred south of the Redding commercial section of Route 7 near 139 Ethan Allen Highway.
A ruptured tank on the truck spread diesel fuel across about a quarter mile of the highway.
State highway crew was called to sand the road.
Fire police have detours set up at Route 102, Branchville Road, on the south, and at Florida Hill Road, north of the crash scene.
The road was reopened around 6:10 p.m.