From:
Amber Wise <amber.wise**At_Symbol_Here**GMAIL.COM>
Subject:
Re: [DCHAS-L] School Incident with Dry Ice
Date:
Feb 29, 2024 22:05 UTC
Reply-To:
ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
Message-ID:
<CAGtjs7G4U3DkSXs4nH3UWYh1KCqwZBga9YamR9Q6qA6kk=VPOg**At_Symbol_Here**mail.gmail.com>
In-Reply-To:
<FBE01CA2-655E-4C00-BF10-590DA8FEB9D5**At_Symbol_Here**ilpi.com>
Seeing as how dry ice is more dense than air and small children breathe closer to the floor, I could envision a closed room "filling up" with CO2 gas and pushing out adequate oxygen for them.
some back of the envelope calculations (I hope I got all my unit conversions?.....it's been awhile since I've taught undergrads chemistry) for a 10x10x3.5 meter room, the lower half of the room's volume is 170,000 Liters.
If half of a 10 pound block of dry ice sublimates (5lbs) = 51.6 moles = 1240 Liters of CO2 (using ideal gas law and room temp). That looks to me like 0.7% by volume. According to some quick googling, those levels are dangerous and can lead to dizziness, nausea and worse.
I can’t think of any scenario with dry ice in this situation that would have caused this. You’d have to a significantly elevated level to feel something, at least 2,000 to 5,000 ppm, and the amount of CO2 you can bring into a classroom is what, a couple of pounds? The room would have to be hermetically sealed or you’d have to be huffing the stuff.
Rob Toreki
======================================================
Safety Emporium - Lab & Safety Supplies featuring brand names
Fax: (856) 553-6154, PO Box 1003, Blackwood, NJ 08012
I do not have any additional details. Although I do suggest anyone working with hazardous materials with groups (or otherwise) to do a risk assessment and have appropriate controls in place as well as plans for any incidents that could occur.
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