From your site you posted.
'A properly functioning burner, whether natural gas or liquefied petroleum gas (LPG), has efficient combustion and produces little CO"
Warnings:
* Never leave a car running in a garage, even with the garage door open.
* Never burn charcoal in houses, tents, vehicles or garages.
* Never install or service combustion appliances without proper knowledge, skills and tools.
* Never use a gas range, oven or dryer for heating.
* Never operate unvented gas-burning appliances in a closed room or in a room in which you are sleeping.
Adapted from "The Senseless Killer," U.S. Consumer Product Safety Commission, Washington, D.C.