[jkumin]

Hi: Propane is heavier than air and leaks will collect in low spots. Natural gas is lighter than air and leaks will float up and out through vents or as doors and windows are opened, rather than collect. That is why use of propane appliances is typically a building code violation in basements. Propane is allowed on the first floor and above as it is assumed any leaks will find a way to disperse. They can''t in a basement - or a boat hull.