One lane (of three) was blocked on the northbound carriageway just after junction 8 (A674 Millennium Way, Chorley).
Police, fire crews and paramedics attended, but North West Ambulance Service said no-one has been seriously injured.
National Highways say the lane closure was in force between Chorley and junction 9 (Preston South, Blackburn, Burnley, M65) whilst the vehicles are recovered.
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It led to queuing traffic back to the motorway interchange at Clayton Brook before the lane was reopened at around 10am.