Question Which gas would cause concern due to a faulty exhaust system? Answers Oxygen Carbon monoxide Nitrogen Explanation A leaking exhaust system can introduce carbon monoxide, which is poisonous, into the cab or sleeper berth. Take a FREE Practice Test Now This questions appears in the following tests: Arkansas Knowledge Test Class A , New Hampshire Knowledge Test Class A , Maine Knowledge Test Class B , Michigan Knowledge Test Class B , New Mexico Double , Vermont Double , Alabama Tank , Kentucky Passenger , South Dakota Passenger ,