From: "Wilhelm, Monique" <mwilhelm**At_Symbol_Here**UMFLINT.EDU>
Subject: Re: [DCHAS-L] HCl concentration and hazard
Date: Fri, 3 Mar 2017 23:29:26 +0000
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 1109037139E1524980CF9CBEB2476618010AE4ACCA**At_Symbol_Here**
In-Reply-To <83CA7C67-F36F-4C30-B626-4E930E9E9902**At_Symbol_Here**>

Okay, I will put in my two cents.... I have already dealt with addressing this issue with a local high school teacher who uses my labs for her classes. Believe it or not, her biggest concern was over making hydrogen gas.

If the teacher themself is not familiar or comfortable enough with HCl to want to use 6M, they probably aren't knowledgeable enough to teach the students safe handling of it. Would a risk assessment cover all of this? Once again, not is the teacher isn't knowledgeable enough. I will tell you why below.

- Is there a significant hazard difference between 6 M and 3 M HCl in the high school lab setting? For someone like me, who frequently works with 12M HCl, I would be comfortable having high school students in my charge use it when there is good ventilation. This is because I do not think there is a significant difference between 3M and 6M during a risk assessment; they both burn eyes and skin and should be treated the same during an incident, be it spill or exposure type. But, my biggest concern isn't really the spill or dermal contact incident, which many teachers will know how to handle and be prepared for, but inhalation because this usually does not get considered for some reason. Because I am asthmatic, I am probably overly aware of inhalation hazards. Would the teachers easily recognize this? When considering inhalation, 6M HCl solutions bother me more, but still should not be a problem as long as no one is putting their face up to the stuff and there is good ven!
tilation in the room and used in small volumes. But, would the teacher be prepared if the students were to spill the stock bottle in the room? Once again, no matter if it is 3M or 6M, the teacher will likely treat the situation the same. So, I would say, use the 6M. It is likely that the biggest hazard comes when the teacher is making the solution, no matter if it is 3M or 6M.

- How would you determine this difference from GHS (or other) information available for these solutions? Many teachers use Flinn as their source for chemicals and their SDS is at (Fishersci uses 2 separate SDSs, but with the same hazards: and It treats 1M, 3M, and 6M in the same SDS. So, assume the same level of hazard and use 6M if you are going to let students use 3M!!!

- Does the choice of which approach (lab, demo, avoid the activity) impact the educational value of the class? I know that there is a lot of debate over this, but I am a firm believer that middle-of -the-road students get more engaged in the learning when they are doing something hands-on and generating data that is their own and do learn better due to being more engaged. For advanced, motivated students, it probably doesn't matter as much.

Sorry for being so long-winded to come to the same conclusion each time. But, it seems an easy decision to me. But, not obviously to the teachers.

Monique Wilhelm
Laboratory Manager/Adjunct Lecturer/Chem Club Co-Advisor
Department of Chemistry & Biochemistry
University of Michigan-Flint
Flint, MI 48502

-----Original Message-----
From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of Stuart, Ralph
Sent: Tuesday, February 28, 2017 8:26 AM
Subject: Re: [DCHAS-L] HCl concentration and hazard

> I also noticed that there were no instructions on what to do with the waste solutions.
Some of the high school teachers pointed this out as a significant concern, as well as the difference between the hazards of the preparation steps that they would be doing compared to the hazards of the students' work.

Another issue that arose was concern about where personal and institutional liabilities lay in case of an unexpected chemistry lab event; I know that this is a quite complicated issue, but does anyone know of a good, user-friendly guide on this topic for either high school or undergrad teaching lab settings? I'm thinking more in terms of how a prudent teacher approaches this issue before an event than after one.

Thanks to all for the thoughts people have shared on this topic on list and off.

- Ralph

Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859


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For more information about the list, contact the Divisional secretary at secretary**At_Symbol_Here**

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