When I was a young child, our family escaped near tragedy. Most of the main appliances in the house, as well as the furnace, were fueled by natural gas, but a small leak in one of the gas lines put our lives at risk. As the gas poured into our little house, our family was overcome by the lethal fumes and we lost consciousness. Had we not been discovered by a neighbor who happened to stop by for a visit, we all could have been killed by this dangerous, unseen enemy.