Date: Thu, 4 Nov 2010 22:36:09 -0400
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Rigel Lustwerk <rlustwerk**At_Symbol_Here**VERIZON.NET>
Subject: Re: Peroxide-forming Chemicals
In-Reply-To: <C44FA638-E649-4899-A0B9-C6F916E364DF**At_Symbol_Here**>
=46rom what I understand, at least for the group A, B, C, and D peroxide formers, the groupings are made by mechanism of peroxide formation, not by danger.  It is true that Group A peroxides do not have to be concentrated in order to accumulate peroxides and should be disposed of sooner than many of the others.  However, some in group C, if uninhibited, are only stable for about 24 hours.
Group A:  Form peroxides during storage without evaporation or concentration
Group B:  Form peroxides by evaporation or distillation
Group C:  Peroxide initiate uncontrolled and dangerous polymerization  (the inhibitors used with these compounds often need small amounts of oxygen to be effective, so these should not be stored under inert gas).
Group D:  Uncertain mechanism

Just my two cents,
Rigel Lustwerk

On Nov 3, 2010, at 9:14 AM, ILPI wrote:

This is why I despise all code letters (and numbers) on labels and MSDS's as discussed under the PPE section here: ef/hmis.html

Example: TSCA, CHIP and HMIRS all have code letters, and they all conflict.

Example: HMIS uses code letters for PPE.  Without a magic decoder chart, you don't know what they mean.

Example: NFPA and HMIS have similar, but not identical definitions for their blue, red, yellow sections.  They both have white sections, but those have different meanings.

Example: GHS will use hazard categories 1-4 for flammable liquids with Category 1  being the most flammable and Category 4 the least.  This is in direct opposition to the NFPA and HMIS ratings.

As much as I like GHS, that last one is going to result in *a lot* of folks putting the wrong information on their NFPA signage, that's for sure.

Rob Toreki

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On Nov 3, 2010, at 7:19 AM, Kohler, Christopher E wrote:

Dear DCHAS listers,
I apologize if this has already been pointed out. I just picked up on this thread.
We recently learned that our haz waste group and lab safety group were using different classification systems for peroxide formers.  Not only were they different but they listed them chemical is reverse order.
After looking into it=85 it appears that the two different classification systems originated from the following references:
1.     Prudent Practices in the Laboratory, Handling and Disposal of Chemicals, 1995, National Academies Press.
                    Prudent Practices in the Laboratory designates peroxide formers as Class I, II, III and they are  listed from the LEAST dangerous to the MOST dangerous respectively.
2.     CRC Handbook of Laboratory Safety, Furr, A. Keith, 2000, CRC Press
                   The CRC Handbook of Laboratory Safety designates peroxide formers as Group A, B, C, D and they are listed from the MOSTdangerous to the LEAST dangerous respectively.
Thought you might find this interesting.

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