Highways England and police remain at the scene managing traffic and enforcing speed limits.
The collision, understood to have involved four vehicles, has led to delays on the M65 eastbound between junctions 1 (M6) and 2 (M61, Manchester).
The vehicles have been moved to the hard shoulder, but significant queues remain with tailbacks to the M61 at Clayton Brook.
Police had urged commuters to "obey all signals on the approach to the scene", including enforced speed limits on Matrix signs.
Speed limits were initially set at 50mph but this has now been lifted.
According to Highways England, the congestion is expected to clear between 9.30 and 9.45am, with delays of 30 minutes against expected traffic.
More to follow...