At least 11 ambulances, fire engines and police cars were deployed to the crash scene.
But National Highways said traffic is now flowing again.
It said “Traffic has now been released on the M18 southbound in SouthYorkshire between J4 (Doncaster).
“One lane of 2 remains closed at this time, pending recovery and clear-up works.
“There's approximately two and a half miles of congestion on approach.”