I have heard of people dying from inhaling too much exhaust fumes from a car. The main reason for this is that they are in an enclosed area and the fumes do not have many places to go, so they collect. One of the main components of exhaust fumes is carbon monoxide. It is a toxic, odorless, and tasteless chemical. It is best that if you are going to be running a vehicle and not going any where you should have it outside or in an area with plenty of ventilation.