From: misterbill21225 <0000048b89bc676d-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU>
Subject: Re: [DCHAS-L] hexavalent chromium
Date: Sun, 23 Sep 2018 16:38:10 -0600
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 201809232238.w8NMcD0F023682**At_Symbol_Here**ppa01.princeton.edu
In-Reply-To


Please keep in mind also - the new hex chrome standard has been lowered. Pers samples, area samples, will be affected 

Thanks

Bill Parks



Sent from my Samsung Galaxy , an AT&T LTE smartphone

-------- Original message --------
From: James Duncan <jimandjoanneduncan**At_Symbol_Here**GMAIL.COM>
Date: 9/23/18 12:32 (GMT-07:00)
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
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.
Source:  https://www.esabna.com/us/en/education/blog/does-plasma-cutting-produce-hex-chrome.cfm

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**emu.edu> 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

540.432.4420

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