Toronto Fire Services says 20 homes were evacuated in North York on Tuesday morning due to “explosive levels of gas” in a storm sewer system.

Firefighters, police, and Enbridge were all called to the scene of the underground gas leak, located in the area of Judy Sgro Avenue and Jim Baird Mews, near Highway 400 and Sheppard Avenue West.

The townhomes that were evacuated spanned a four-block radius, according to Toronto police. A spokesperson for Toronto Fire Service said the homes were mostly vacant at the time.

Residents were allowed to return to their homes shortly before 11 a.m. and no injuries were reported.