The eastbound lanes of Highway 401 have reopend at Trafalgar Road in Halton after a crash involving two tractor trailers.

The Ministry of Transportation says the collision occurred on the highway somewhere between Trafalgar Road and the Highway 407 ramps sometime before 10:39 a.m. Thursday.

The on ramps from Trafalgar Road to Highway 401 are also closed.

OPP Sgt. Kerry Schmidt said one of the truck drivers was trapped in his vehicle with serious or critical injuries.

An ORNGE air ambulance was sent to the scene to transport him to a hospital trauma centre.

ORNGE said the victim is a man in his 50s. He was taken to St. Michael's Hospital for treatment.

The westbound lanes of the 401 were also closed for a short time to allow for the helicopter to land.

Earlier on Thursday, all but one eastbound lane on Highway 401 was blocked at Winston Churchill Boulevard in Mississauga after a multi-car crash

Schmidt sayid that at least two transport trucks and a number of passenger vehicles were involved in the crash, which occurred at around 8:30 a.m.

He said that four vehicles sustained “significant damage” while a few others sustained “less severe damage.”

Two people were taken to hospital following the collision but their injuries are not believed to be serious. One of those people was initially trapped in their vehicle and had to be extricated by emergency crews, according to Schmidt.

“It looks like traffic was probably slowing down and one of the vehicles hit the back of traffic and sheared off the trailer and then destroyed two vehicles,” Schmidt said. “Two people were taken to hospital. Amazingly they were conscious and breathing. Looking at the damage it certainly could have been far worse.”

The highway was initially completely blocked but one left lane did reopen at around 9:30 a.m.