The incident happened around 10 a.m. Tuesday near Blue Jays Way and Wellington Street.
The affected gas line, which Toronto police said has been “blown,” is located on a street behind a restaurant and supplies gas to a building under construction.
There are currently no reports of injuries.
As a precaution, residents of two apartment buildings at 250 and 270 Wellington Street have been evacuated, Toronto Fire told CP24.
The TTC brought in buses to provide shelter to those directly affected.
Toronto Fire is advising residents of other buildings in the immediate area to “shelter in place.”
Police have also restricted access to roads near the spill.
Crews from Enbridge are now working on site to contain the leak, which Toronto Fire said “does not appear to be leaking gas into surrounding buildings.”
More to come.