A row of townhouses in Toronto’s north end was evacuated for about an hour after a gas leak was reported Monday morning.

Toronto police said they received reports of a natural gas leak at about 9:45 a.m., near the Don Valley Parkway south of Highway 401.

A mattress was thrown over the railing hitting a gas valve causing the gas leak, officials said.

A row of townhouses on York Mills Road was evacuated and traffic was being diverted from the area.

Buses were brought in to provide shelter for residents while a team from Enbridge tended to the leak.

Police say gas was shut off to the area some time before 10:30 a.m., and the public has since been allowed to return to the area.

Emergency management crews and chemical experts have been called in to assess the situation.

The building superintendent warned tenants to be cautious of where they throw their garbage to avoid repeating an incident of the same nature.

With a report from CTV Toronto’s Tamara Cherry