From: Bruce Van Scoy <bvanscoy**At_Symbol_Here**TWC.COM>
Subject: Re: [DCHAS-L] C&EN Safety Zone blog: [New post] "We felt the explosion rattle the floor and walls eight floors up."
Date: Tue, 26 Apr 2016 20:23:49 -0400
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: 000901d1a01b$11fe61a0$35fb24e0$**At_Symbol_Here**
In-Reply-To <0E896CBD-7B93-4390-9852-808E47A42EB1**At_Symbol_Here**>

Today I just caught that in ACGIH's 2016 TLV and BEI booklet a category
includes EX or an Explosion hazard: the substance is a flammable asphyxiate
or excursions above the TLV could approach 10% of the LEL limit. Included
on the NIC for addition of the EX Explosion Hazard endnote include:
Acetylene, Ethane, Hydrogen, L.P.G., and propane.
I think we will need to consider this in the future.
Routinely, I have considered the TLVs to be much lower than 10% of LEL
requirements. But, I never made a direct comparison. Thanks to the ACGIH
for another reason never to exceed the ALs!
I will now.

-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**] On Behalf Of
Secretary, ACS Division of Chemical Health and Safety
Sent: Tuesday, April 26, 2016 7:54 AM
Subject: Re: [DCHAS-L] C&EN Safety Zone blog: [New post] "We felt the
explosion rattle the floor and walls eight floors up."

>> >I can empathize with this researcher.... I work with Hydrogen, CO, and
O2 in the lab and did not consider the issue with fires.... I will conduct a
SAP review and modify our current working conditions. I teach a safety
course and work closely with SAChE but and aware of the LFL and UFL of H2...
we as researchers get tunnel vision.

I've had three conversations with chemists in the last couple of months that
emphasize this point. They ask me about the safety and reactivities of the
molecules they're using in very small quantities, but aren't concerned about
the fire and other hazards of the solvents and other chemicals they use as
tools to conduct the work with. After all, they've been using those
chemicals since first year chemistry...

There is a significant challenge in developing a balanced overall risk
perception for chemists in the laboratory setting. I'm not clear how to
address this issue.

- Ralph

Ralph Stuart
Division of Chemical Health and Safety
American Chemical Society

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