Air will oxidize copper, especially in the presence of acid fumes and moisture. We have produced copper sulfate by bubbling air through dilute (1-2 M) sulfuric acid in a test tube with copper wire. The scale will be whatever salt deposits from available other ions (carbonate, sulfide, oxide, sulfate). Copper sulfate deposits would dissolve in water (slowly), so the deposits may be a carbonate or mixed oxide and carbonate.
The scale itself is not likely dangerous, but it should be investigated whether this atmosphere is safe for lungs.
Richard York
Coordinator of Chemistry Labs
Wittenberg University
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU]On Behalf Of scrooks**At_Symbol_Here**PPEPPRO.COM
Sent: Monday, November 05, 2012 12:02 PM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: [DCHAS-L] help w/ mystery scale on exterior of copper pipes
I was recently asked to look at a dark blue scale appearing on the exterior of some copper piping and determine possible causes and if any human health risk is likely. I am asking here primarily for anyone who's possibly seen this blue scale appear in similar installation. I don't want to take anyone's time going deep as this is a paid consulting task and I do have access to other resources (and this one appears complicated.) This group has seen and experienced so much collectively though that I couldn't pass it up as a great sounding board. Then again, most on this list are being rewarded in some manner through the advice, ideas and answers obtained through the group so my shame isn't too unbearable.
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