All lanes are now open after the accident on the southbound carriageway, but the earlier closure has led to congestion between J24 (Ashton-in-Makerfield) and J23 (Haydock).
Delays should start to ease, but there is currently around five miles of queuing traffic back to junction 27 (Standish).
Highways say the congestion is adding around 30 minutes to normal journey times.
