Huron County OPP say three people have died in a single-vehicle crash on Brussels Line between Cardiff Road and Browntown Road.
Emergency crews were called to the scene around 7:45 a.m. for the collision.
Police say a male driver and two male passengers in a pickup truck were pronounced dead at the scene.
A fourth person was transported to a local hospital and then airlifted to London with life-threatening injuries.
The identities of the driver and deceased passengers are being withheld pending notification of next of kin.
Brussels Line between Cardiff Road and Browntown Road was expected to be closed for several hours for the police investigation.
