The accident involved a collision of four lorries on the motorway in Bedfordshire southbound between junctions 12 and 13 at about 07.00am.
Highways England said the traffic jam caused by the jam spillage had now been cleared, but warned of continuing delays. Other routes, including the A5, had extra traffic.
The organisation warned drivers of the accident using Twitter (see tweet below).
Police said no-one was harmed in the accident.
Meanwhile, a fire on a lorry carrying 1,000 crates of pre-packed food closed the M1 northbound in Nottinghamshire in January 2.
The incident occurred at about 03.00am at Trowell services near junction 25. The service station and one lane remained shut for most of the morning.