Do you have any appliances with a pilot light? It could be a stove, a heater or anything else that runs on natural gas. So what is a pilot light? It’s an older mechanism that is used to ignite the natural gas by having a small but constant amount of gas fed to a small flame. In modern appliances different, safer, and more efficient methods are used to accomplish ignition, but if you live in an older home, it is possible that you have an appliance that still employs this method.
There are some safety concerns with pilot lights. While appliances using them should be equipped with a sensor that shuts off the gas fed to the flame when it detects that it goes out, these could malfunction and cause a danger of a gas explosion when reignited. When relighting an extinguished pilot light, make sure that you ventilate the area and check for the distinctive smell of natural gas.