From:
Jonathan Dannatt <jdannatt**At_Symbol_Here**UDALLAS.EDU>
Subject:
Re: [DCHAS-L] Input on chemical incident
Date:
Feb 8, 2024 23:56 UTC
Reply-To:
ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
Message-ID:
<CAEiU9vDARJQXXf+jS4nK=uLxY-fSqjV_56m+NRS0V+n=8aUK9w**At_Symbol_Here**mail.gmail.com>
In-Reply-To:
<DM3PR08MB9587E53F1F271D763D1B5696A3452**At_Symbol_Here**DM3PR08MB9587.namprd08.prod.outlook.com>
Hey Alex,
Thanks for sharing.
It sounds like everyone was safe after this incident, which is wonderful. Unfortunately, I don't have any exact data regarding this mixture, but I wouldn't expect polymerization without other material.
A possibility to consider though: Methanol and ethyl acetate are both relatively low boiling solvents (64 C and 77 C, respectively). While I doubt conditions were such that they would boil, mixing solvents can be (and often is) an exothermic process. This will raise the temperature of the mixture which increases the vapor pressure. With an extremely small headspace, even a small increase in temperature and vapor pressure could be sufficient to cause an issue like what you described. To test this, you can ask the lab to measure the change in temperature when the components are mixed at a smaller scale.
Some things I would suggest and love to hear others input on (specifically on point 2):
1) Like you said, waste containers should only be filled up to 80% to allow for sufficient head space.
2) If large amounts of a liquid are added together quickly, (say 2L of ethyl acetate added to 1.5 L methanol), the waste container should not be immediately sealed. I personally would cap it with a loose cap for a few minutes to allow time for the solution to form and cool.
Again thanks for sharing : )
Best,
Jonathan
Good morning,
We had a small hazardous waste incident in one of our labs recently, and I am trying to help the lab gather information on potential causes. A four-liter amber glass bottle of chemical waste containing 50% methanol, 44% ethyl acetate, and
an assortment of six p-phenylenediamine antioxidants (PPDs) pressurized and broke open. The bottle was tightly capped and very full, it only had about 1.5 inches of space left at the top. The bottle broke open at the bottom of the bottle in a jagged formation.
No polymerization of the contents was observed, but some speculated an event like that could have led to the pressurization of the container. I have already informed the lab that they should not fill waste containers more than 80%.
I have not been able to find information on similar events involving PPDs. Any input or information this group could provide about what may have led to this event is greatly appreciated.
Regards,
ALEX HAGEN, CCHO
Laboratory Safety Inspection Program Manager
Environmental Health & Safety Department
Research & Occupational Safety, Laboratory Safety Inspection Program
Hall Health / Box 354400 / Seattle, WA 98195-4400
206.221.2339 / mobile 206.713.5267 / fax 206.616.3360
fischera**At_Symbol_Here**uw.edu /
www.ehs.washington.edu

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