From: Jeff Tenney <jtenney46**At_Symbol_Here**ATT.NET>
Subject: Re: [DCHAS-L] hexavalent chromium
Date: Sun, 23 Sep 2018 17:52:26 -0400
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 201809232152.w8NLqRN2028389**At_Symbol_Here**



If disposal is required then a TCLP should be done on the water after it is well mixed (A full one may not be required if they know what possible characteristics the water has of the 43 listed). That way the sludge can also be tested since the sample will be acidified. If the disposal of the water is because bacteria contamination they may want to look a product like GreenCut plasma fluid. You also have to be aware of what the local POTW will also except. They may have a limit for things like iron, nickel, and copper that are not covered by the EPA testing. Once he has that information he can get the correct testing done. It is nice to see someone concerned and not just dumping down the drain in the hope they never get inspected. They should be commended for that. The proper disposal will depend on the levels found but any commercial water treatment facility should be able to treat relatively cheaply, if it cannot go to the POTW.


Hope this helps,



Sent from Mail for Windows 10


From: James Duncan
Sent: Sunday, September 23, 2018 5:12 PM
Subject: Re: [DCHAS-L] hexavalent chromium


Hex Chrome is given off when stainless steel is cast, welded, or plasma cut. These thermal processes cause a small percentage of the Chromium in stainless steel to be converted into Hex Chrome. The chromium in stainless steel is not originally hexavalent, but the high temperature involved in the plasma cutting process results in oxidation that converts the chromium to a hexavalent state.


Disposal of the bath water (after analyses) can be accomplished by contracting with an approved waste disposal company.  Also, the work area should be inspected to ensure that the off gas is not at levels that are detrimental to employees.


Jim Duncan, PhD

Senior Consulting Scientist




On Sun, Sep 23, 2018 at 11:18 AM Laurie Yoder <laurie.yoder**At_Symbol_Here**> wrote:

I'm asking a question on behalf of someone who runs a small machine shop. They use a plasma cutter with a water table, mostly for steel, but also some stainless steel. The question is whether hexavalent chromium will be present in the water bath (along with the iron, copper, and whatever else is in there, in their respective oxidation states). Does anyone have experience with these systems and proper disposal of the bath-water?



Laurie M. Yoder
Assistant Professor of Chemistry and Chemical Hygiene OfficerEastern Mennonite University



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