Which gas would cause concern due to a faulty exhaust system? 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. This questions appears in the following tests: Alabama Tank Michigan Class B Knowledge Test Michigan Tank Missouri Class A Knowledge Test Missouri Class B Knowledge Test Missouri Passenger North Carolina Double Ohio Class A Knowledge Test Rhode Island Double South Carolina Class B Knowledge Test Vermont Class A Knowledge Test Virginia Class A Knowledge Test