Toronto Fire says it's gotten to the bottom of a mysterious odour that prompted over 80 calls from residents complaining about a gas-like smell.

Capt. David Eckerman said calls about the smell came from across the southern part of the city Tuesday night and Wednesday morning from The Beach, Queen Street, Dundas Street, Keele Street and The Queensway.

Crews traced the source of the stink to a grease manufacturing business on Titan Road in Etobicoke.

Eckerman said the plant had been using a mix of chemicals that created an odour resembling ethyl mercaptan — an additive with a skunk-like smell used in natural gas.

The manufacturing process takes place about once a month, Eckerman said, but the atmospheric conditions this week meant the smell ended up going across the city.

There was no risk to public safety, Eckerman said.