The crash happened between southbound junctions 23 (Haydock Island, A580) and 22 (Warrington North, A49) at around 7.50am.
Traffic had to be stopped whilst emergency services attended the scene and vehicles were moved off the carriageway.
It has led to significant delays this morning, with Highways warning of hour-long delays for those passing the scene.
It said it expects normal traffic conditions to resume by around 11.45am.
A Highways spokesman said: "Delays are now over 1 hour and there is slow traffic from J25 (over 6 miles).
"Please use alternative routes (if possible). Our officers on scene are working hard to clear the vehicles involved and release traffic as soon as possible."
It is not clear at this stage if anyone has been injured in the incident.
North West Ambulance Service have been approached for comment.
Lancashire Fire and Rescue Service are also assisting at the scene and have been approached for comment.
More to follow...
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