Lambton OPP, St. Clair Township Fire and Lambton EMS were called to a two-vehicle crash Wednesday morning that resulted in a gas leak.
It happened just after 7 a.m. at Petrolia Line and Mandaumin Road in St. Clair Township.
Lambton OPP said three people were taken to hospital for treatment of non-life threatening injuries.
Repairs by Enbridge Gas are expected to take some time to complete and surrounding roads are closed for the time being.
Mandaumin Road between Lasalle Line and Rokeby Line is closed, as well as Petrolia Line between Fairweather Road and Waterworks Road.
Motorists are advised to take an alternate route.