West Yorkshire Police were called to the M62 at Junction 30 southbound near Oulton at 4.52pm to attend an accident involving three cars.
West Yorkshire Police are on the scene and drivers are being warned to avoid the area.
It is not yet known if any of the individuals involved have sustained serious injuries.
Cars on the M62 are queuing back to Junction 28 near Tingley.
A driver at the scene said traffic was now at "a complete standstill".
Two fire crews attended the accident.
A spokesman for West Yorkshire Fire said: "One person was trapped and was released from vehicle into the care of ambulance crews prior to being taken to hospital.
"A further vehicle that had been involved in the initial collision was located 200 yards away with a further casualty trapped.
"This casualty was released by fire crews and handed over into the care of the ambulance."
The M1 is also experiencing heavy congestion after a crash between Junction 42 at Leeds and J41 at Wakefield.
One of the four lanes is closed.
Both crashes are causing tail backs on the M621.
5 live Travel tweeted: "M62 Eastbound closed long delays, queueing traffic due to accident, three cars involved at J30 A642 (Rothwell). Congestion to J28 (Tingley). Traffic is also very slow Westbound due to onlookers. Note change of direction."
Highways England said: "M62 J30 Eastbound, accident across all 3 lanes. An up and over diversion is in place.
"Use alternative routes where possible. We have traffic officers and West Yorkshire Road Policing Unit on scene and dealing to try to get this cleared as soon as we can."