The M18 northbound carriageway between junction 6 (Waterside Interchange) and junction 7 (Langham Interchange) has been closed following the crash.
A Highways England spokesman said the incident involved a car and an LGV. It is not known if any of the occupants of the vehicles have been injured in the incident.
Lane three on the southbound carriageway is also currently closed.
Eyewitnesses reported seeing a number of dead animals on the road, including a number of pig carcasses.
The incident happened at 11.49am today.
National Highways attended the scene to assess the situation and put in place clear-up and recovery. Emergency services have also attended.
The northbound carriageway is currently expected to be closed until mid-afternoon today to enable full clear-up and recovery.
Clearly signposted diversions are in place.
Further updates will be issued from National Highways through www.trafficengland.com and the Twitter account @HighwaysYorks.