The counterweight, part of the crane meant to prevent it from tipping, was located on top of the 8 The Esplanade residential building after it fell approximately 20 feet, Toronto Fire District Chief Stephan Powell told CNN.
Authorities were alerted to the incident at the intersection of Esplanade and Yonge Street just after 2 p.m., he added.
The top six floors of the condominium are mechanical rooms used for building maintenance, so no residential units were damaged, according to Powell.
City structural engineers are currently on site assessing the damage caused by the crane, Powell said, adding that no injuries were reported from the incident.
CNN has reached out to Del Property Management, which owns 8 The Esplanade, for comment.