The Windsor Police Service Arson Unit and Ontario Fire Marshal have been called to a house in the city's west end.
Windsor police and firefighters responded to a one-storey structure in the 3600 block of Bloomfield Road around 8:30 a.m. Monday.
Four individuals found inside the home were taken to hospital with serious injuries police said.
One of them, a 35-year-old man, was arrested at the scene and remained in medical care under police custody.
Windsor Fire has stated that two individuals have been transported to a Hamilton hospital for further treatment.
Damages are estimated at $50,000.
Bloomfield Road between Prince Road and Watkins Street was closed for the investigation.