A man was found dead in a car in Queens yesterday, seated next to an open 10-gallon bucket of an unknown chemical, police said.

Cops were called at 5:45 p.m. by a teen who saw the unconscious man inside the car, parked by a Home Depot at 31st Avenue and 124th Street in College Point.

Ambulance crews found the car running with the windows up, and called in a hazmat team.

Police are investigating whether the man was trying to use the chemical fumes to kill himself, said sources.