York District Police said the incident happened shortly after 11 a.m. Friday at a location near Woodbine Avenue and Stouffville Road in Whitchurch-Stouffvile near Gormley.
Two people were injured and the incident involved a crane, although few other details have been released by police.
A man was rushed to hospital by ambulance with serious injuries. The other man was transported by ground ambulance to a local hospital, although the extent of his injuries is unknown at this time.
An investigation into the incident is now under way, the Ontario Ministry of Labor has confirmed.
