Forgot what I was searching for now, but this old post caught my attention. Years ago I had a new water well put in that produced way more water than we could measure, but also produced gas with the really strong rotten egg smell. Not having anymore money to throw in the ground at the time, I connected to that well for about 5, 6 months til I could drill again in another location. During that short period of time all the copper in the place turned black, the plumbing fixtures corroded, silver corroded, cheap jewelery became junk, I lost a few electronic items, and the colorfully painted beer stein from Germany turned grey/silver. Interestingly the red came back, but none of the other colors. Bad stuff man. I can't tell from the picture, but it looks like this house could be in the country and likely served by a water well. Erby, would that be an accurate guess? I don't know if my situation had any affect on the building wire besides appearance; I would say probably not. Does anyone know if the hardness (or softness) of the copper could be changed by exposure to this gas? I did have a jeweler tell me one time that clorox bleach could change the properties of gold enough to make it more brittle. I suppose he could have been blowing smoke at me. I'm not a chemist. (May be a good thing!) At any rate, if I were to encounter a property like this now, electrical concern aside, the issue would definately be worth bringing to the client. It was pretty nasty stuff to live with and costly. Might explain why the house was vacant.