Glad for more information Blueflag.
You’re welcome. Methane is a very natural and beneficial component of God’s natural carbon cycle. It has both geologic and metabolic sources. It is odourless and NON-TOXIC. Biologically, in terms of tonnage cycled, it is respired/excreted far more than it is metabolised (eaten as ‘food’).
DO NOT fear methane. You don’t want it in you water well, and you don’t want it building up in confined spaces (it IS natural gas after all) and like most ANY gas can be suffocating if it displaces atmospheric gases (ie in a coal mine) but otherwise it is HARMLESS to humans.