A Markham senior has died in what appears to be a tragic accident.

The 73-year-old and his wife, 69, were found in the bedroom of their home near Highway 7 and 9th Line Sunday morning.

Carbon monoxide from a running car in the garage had seeped into the couple's house, killing the man and poisoning his wife. Police are still investigating, but they believe the vehicle was left on by accident.

The woman is in hospital with non-life threatening injuries. No names have been released at the request of the family.

A carbon monoxide detector was found in the home, but it was located in the basement. Experts say you should have one on every floor.