Monona:
I got a very good laugh at your analogy. I immediately thought of Gelifte fish, but the more accurate description would be (from my wife's Swedish heritage) Lutefisk. This is where the white fish is soaked in lye for a couple of days. Yes-even more disgusting than it sounds (at least for me).
Back to the analogy. Using your logic, vinegar should be banned by the EPA or OSHA or Good Housekeeping or someone.
Where concentration does count (I know my friend Alan will weigh in on this) is that for some caustics a dilute concentration is more damaging to the eyes since it is more soluble.
Bottom line-concentration does count. More is worser-[sic] (usually), especially if it is fuming (not as in angry).
Anyway---.always enjoy your take on things Monona. As they say in your business, "Rock On".
Regards,
Zack
S.Z. Mansdorf, PhD, CIH, CSP, QEP
Consultant in EHS and Sustainability
7184 Via Palomar
Boca Raton, FL 33433
561-212-7288
From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of Monona Rossol
Sent: Monday, February 27, 2017 3:32 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] HCl concentration and hazard
It irks me that the the word "irritation" was used for a dilute form of HCl. If you look up the toxicological definition, an irritant is a chemical that can cause redness, swelling and pain that is reversible. The example is jalapeno. Instead, the term is wrongly and commonly applied to dilute corrosives.
A corrosive is trying to convert you into liquid mush. It can do it fast at high concentrations and much slower at low concentrations. But the damage it does at either concentration is not strictly reversible. The light damage to skin cells from a dilute corrosive just heals fast as damaged skin cells quickly replace themselves.
The true irritant doesn't damage skin cells and can't liquify you at any concentration -- although Santa Fe green sauce may be an exception.
Monona Rossol, M.S., M.F.A., Industrial Hygienist
President: Arts, Crafts & Theater Safety, Inc.
Safety Officer: Local USA829, IATSE
New York, NY 10012 212-777-0062
-----Original Message-----
From: Jarral Ryter <jryter**At_Symbol_Here**WESTERN.EDU>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Sent: Mon, Feb 27, 2017 1:31 pm
Subject: Re: [DCHAS-L] HCl concentration and hazard
Interesting side note:
Toilet bowl cleaner is 9% HCl and will burn your bum. A friend sat on some the custodians left on the seat. She wasn't happy.
Hmm. If they have goggles and wash up spills I don't think it is going to hurt anyone. If you spilled some on a tender area and didn't wash it off on the other hand......
Jarral Ryter
Senior Chemistry Lecturer/Lab and Safety Manager
Western State Colorado University
970.943.2875
western.edu
jryter**At_Symbol_Here**western.edu
-----Original Message-----
From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of Stuart, Ralph
Sent: Monday, February 27, 2017 9:11 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [DCHAS-L] HCl concentration and hazard
Over the weekend, several of us attended a workshop to discuss chemical hazard assessment needs with high school teachers. As the example activity to assess the hazards of, we used the "Hollow Penny" activity described at http://zushma.com/images/Hollow_Penny_Activity.pdf
This protocol calls for 6M HCl to be used to digest the zinc interior of the penny. One of the teachers commented that they are uncomfortable with using HCl this concentrated with the teen age students she oversees, so she uses 3 M HCl and lets the penny digest over the weekend so there's enough time to do the job. Other teachers use the 6 M HCl in a lab setting (i.e. students do the hands on work), whereas others said that they did this only as a demo (i.e. the teacher was the only person who touched the acid until the hollow penny is decontaminated). Some teachers avoided this activity altogether. Interestingly, the SDS's we found on the web for HCl indicated that any concentration above 0.1 M has both the corrosive and irritant designations. The 0..1 M SDS I found showed only an irritant designation.
We are not second guessing anyone's professional judgement as to which option they chose. Previous discussion that day made it clear that factors such as 1) the facilities and equipment available, 2) the nature of the students involved in the class and 3) the availability of PPE all made a difference in what people decided to do. These factors vary widely from school to school.
There are three questions we'd like the list's thoughts on:
- Is there a significant hazard difference between 6 M and 3 M HCl in the high school lab setting?
- How would you determine this difference from GHS (or other) information available for these solutions?
- Does the choice of which approach (lab, demo, avoid the activity) impact the educational value of the class?
Thanks for any help with this.
- Ralph
Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859
ralph.stuart**At_Symbol_Here**keene.edu
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