Nobody else lived at the house at that time. (Since I rent I bet this mystery could be easily solved.) Well, if it were green I would have suspected one of you old codgers were in my place and forgot your oxygen tank.
Well that is confusing. I hope there is a standard color coding, ISO maybe, for compressed gases/liquids/foams(?). (Of course there isn't any consistent standard enforced. The wiring in my house makes that very clear.) That could lead to one hell of a surprise if someone wanted to put out a fire and grabbed an oxygen tank by mistake. lol
