From: Luis A Samaniego <l-samaniego**At_Symbol_Here**NORTHWESTERN.EDU>
Subject: Re: [DCHAS-L] ether for anesthetizing fruit flies
Date: Wed, 5 Feb 2020 15:29:18 +0000
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: MN2PR05MB6432A507B62678AC7014F23296020**At_Symbol_Here**
In-Reply-To <860557934.885076.1580914769840**At_Symbol_Here**>

Please be aware that diethyl ether can produce explosive peroxides when exposed to light and air. If planning to use this chemical, ensure to have peroxide test strips to monitor peroxide formation.

You may obtain the peroxide test strips from the link below:

URL Link is below:,MDA_CHEM-110081



Luis Samaniego, CSP

Sr Laboratory Safety Specialist


Northwestern University

Research - Safety


303 East Chicago Avenue

Ward B-106, W223

Chicago, IL 60611








From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU> On Behalf Of Monona Rossol
Sent: Wednesday, February 05, 2020 8:59 AM
Subject: Re: [DCHAS-L] ether for anesthetizing fruit flies


Margaret,  That's all very rational and interesting, but I don't think the law is written that way.  I got the same rationale from the museum community that thought there was no problem because they were killing things to save important art and artifacts.  It seems that the motivation for killing is not relevant.  It is the killing that counts.


I also find it odd that you would assume a registered pesticide would automatically be one that would inflict pain.  CO2 is a registered pesticide for certain uses, as are many other painless killers.  The list is long.


The safety of the pesticide you choose is a factor, but it is NOT a choice you can make for yourself based on the considerations you list below.  Instead, you can google exempt minimum risk pesticide ingredients  (See NPIC "Minimum Risk Pesticides" web page, including links to EPA's lists of substances considered to be "minimum risk,"  If you can use something on this list, you are home free.  Be very careful if you pull up the whole law, because there are two lists, one for "active" and one for "inactive" ingredients.  You cannot legally used one of the inactive ingredients to actually be the killer of the critters.  And CO2 is on that inactive list.  Instead, CO2 has to be registered for the use.


And if you really think something is so safe that it belongs on that list, there is a long process for getting the list amended.  Or you register your safe substance and process as a pesticide and sell it.  That's what Finn Scientific did when they registered what is essentially an Alka-seltzer as a pesticide for this particular purpose.  


There may be some kind of exemption for research labs.  But I'm pretty sure there isn't one for schools where the product is "education" rather than "research."


I've been in touch with the Enforcement Coordinator and Liaison in the office of Pesticide Programs.  She's already told me that this is how it is.  But she promised a clear statement to this effect which is being vetted by the EPA lawyers.  She is preparing this statement to help me and a couple of other responsible people in the art conservation community to make the issue clear to museums. When I email her today, I shall also refer to this projects you people are doing in schools because it also is being done obviously all over the country just like the museums all over the country were making up their own formulas and procedures.  I'll not mention names or this forum, but maybe I can get the statement inclusive enough to apply here.  It's worth a try.


Best I get right at it while we still have an EPA.  Oy.






-----Original Message-----
From: Margaret Rakas <
Sent: Wed, Feb 5, 2020 5:55 am
Subject: Re: [DCHAS-L] ether for anesthetizing fruit flies





I think this is a situation where the various federal agencies may have varying points of view, some of them quite in opposition to the other.  I also wonder if the EPA folks were aware of regulations promulgated by USDA and other agencies involved in animal research, and/or how the question was posed.


If you're killing flies, or rats, or garden slugs because they are pests— invading your home/office/workplace then yes I agree that a registered pesticide is what is legal and required.


But these fruit flies-or genetically modified rodents, or zebra fish used in research-are not being destroyed because they are pests- they are being euthanized for study.  The means of euthanasia must not only inflict minimal to no pain (generally), it must also not affect the property being studied, whether that's neural development, the effect of various viral vectors carrying gene modifying units, or whatever.  I can't imagine that a registered pesticide used expressly to euthanize animals for scientific research would be in compliance with  either requirement.  Moreover, if the institution received research funding from USDA or other related agencies, it would be in violation of federal animal welfare regulations.  


So- my two cents on the original question is, we use "fly nap" in a fume hood.   That's a combination of triethyamine, methanol and isopropyl alcohol-still flammable, maybe somewhat less so than ether,  but I may suggest to our folks they try triethylamine by itself or the device w/alka-seltzer tablets.  Ether just seems like more trouble than it's worth when there are less hazardous substances.


Good luck with this project (can you at least have them add a fume hood or 2 if they insist on sticking with diethyl ether?)




Sent from my iPhone

On Feb 4, 2020, at 9:33 PM, Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**> wrote:


oooow.  How interesting. The natural history museums also commonly use inert gases or chemicals that are oxygen scavengers for killing critters in containers. 


However,  we recently posed the issue of these practices to the EPA pest people, and found that as soon as you intend to kill a critter, you need to be using a pesticide registered for the purpose.  So I suggest you use one of the products mentioned on this thread registered for the purpose.


It's not a good practice to teach students to break the law, however small the offence. 




-----Original Message-----
From: Jeff <
Sent: Tue, Feb 4, 2020 9:09 pm
Subject: Re: [DCHAS-L] ether for anesthetizing fruit flies

Finn Scientific has a  Carbon Dioxide Drosophila Anesthetizer. Uses an alka-seltzer tablet.


Sent from Mail for Windows 10


From: Ellen M. Sweet
Sent: Tuesday, February 4, 2020 6:07 PM
Subject: [DCHAS-L] ether for anesthetizing fruit flies


Hi everyone,

We are looking to renovate a Genetics teaching lab that has the students using ethyl ether to put fruit flies asleep. This is a common method of doing this, put certainly has its drawbacks when you consider the ventilation strategy (ether vapor is very heavy).

I'm wondering if anyone has been successful in having 12-14 student stations using this chemical in a teaching setting (on the bench) and keeping the exposures and smell down? Keeping in mind that fruit flies will get sucked up into local exhaust if they are too close!…

In addition to floor level exhaust diffusers, what else would you recommend and how many air exchanges for the room?





P.S. I'm pushing for CO2, but may not get what I want.



Ellen Sweet

Laboratory Ventilation Specialist

Department of Environmental Health and Safety, Cornell University

American Chemical Society, Division of Chemical Health and Safety




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