I often drove by a feedlot operation near one place I lived way back. At certain times of the year when the manure was spread, well, I expect you know. The cattle--all thousand of them--were magnificient at producing what many folks called "The smell of money."



Oh, if you are breathing pure O2 for some reason, don't be lighting any matches, lighters or otherwise doing things that make sparks while yer on the tank or while the room is O2-rich. O2 supports combustion. It goes 'boom'.