I see alot of gas leaks, especially at the equiptment. The gas needs to be turned of to make the repair. Gasoila, RectorSeal, any pipe thread sealant that states "use for gas" will work. Just please, know what you are doing and if you are the least bit unsure, call your plumber or utility company and have them do it for you. You don't often get a second chance to fix a problem like that.