Ontario's Ministry of Labour will continue its investigation on Wednesday after an accident at a York University construction site killed one man and injured five others.

A 25-year-old man was killed when a drilling rig toppled to the ground Tuesday afternoon.

Another construction worker was pinned for several hours and four other men were injured when the massive machinery weighing tens of thousands of kilograms toppled near the university's Schulich School of Business at James Gillies Street and York Boulevard at 2:30 p.m.

Crews worked late into the night Tuesday to recover the deceased man's body. His name has not been released.

Another man who was trapped beneath the crane was taken to Sunnybrook hospital just before 5 p.m. after a medical team was able to rescue him without any surgical intervention. He suffered serious leg injuries.

Toronto Sgt. Simon Fraser said that if not for the quick action by firefighters, police and first responders, the pinned man could have also died at the scene.

"They stepped up and they saved the life of a man. They did everything that needed to be done. In an absolutely chaotic matter we all came together," Fraser told reporters at the scene on Wednesday.

The construction was happening on the site of the future York University subway station. TTC spokesperson Brad Ross said that excavation work and tunneling was underway at the site.

"A heavy piece of machinery collapsed or gave way on the site and unfortunately resulted in the death of one individual and the injuries of others," Ross said Tuesday. The work was being done by sub-contracted workers.

The cause of the collapse is not clear but police said that the ground was unstable at the time of the incident.

No students were near the site when the rig collapsed, but classes at York's Seymour Schulich Building were cancelled Tuesday night.