Subject: EMS ???

From: [email-masked] (r3603212)
Date: 20 Jul 1995 03:13:48 -0700

Dose anyone know how to treat the mutagen - EMS (ethyl methanesulfonate; 
methanesulfonic acid ethyl ester) after use it for mutation?

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From: Chuck Staben <[email-masked]>
Date: 20 Jul 1995 12:57:01 GMT

EMS is a reactive, mutagenic chemical.  EMS is volatile, so it should be used in a fume 
hood.  Gloves should be worn, avoid personal exposure.  Standard lab practice usually is to 
make EMS solutions 5% with sodium thiosulfate to stop reaction.  Spills should be treated with 
a large volume of 5-10% sodium thiosulfate.  This treatment renders EMS (at concentrations 
used in mutagenesis protocols) non-mutagenic.  You should usually package all hazardous wastes 
in secure containers for disposal by qualified handlers of hazardous chemical waste.  Disposal 
of chemical waste is an increasingly sensitive issue at the University of Kentucky, and I 
presume, elsewhere.  
You may wish to consult the MSDS for information regarding the use and disposal of chemicals. 
Your University or organization is probably required by law to have access to these documents. 
Some chemical suppliers have online hooks of their chemical catalogs to MSDS info (see Fisher 
Internet Catalog for an example).  
I have found that MSDS are usually very overcautious, giving little idea of how 
hazardous a chemical really is. (Glucose looks hazardous on an MSDS.  I guess it is, if 
ingested in large amounts over a long period of time.)

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From: [email-masked] (Michael Clark)
Date: 20 Jul 1995 23:14:58 GMT

I did EMS mutagenesis of yeast when I was an undergrad.  After the
cells had incubated in EMS, the EMS was destroyed by adding the cells
(with EMS) to 5% sodium thiosulfate.  The cells were spun down and the
thiosulfate solution disposed of.  I believe that we added this
solution to a little more 5% Na thiosulfate and let it sit in the fume
hood for a week or two.  Consult your health protection office on this,
but as I recall, we disposed of it as regular chemical waste (i.e. as
thiosulfate since the EMS was destroyed).

BTW: I echo the comments about doing this in a fume hood, and defintely
wear double gloves.  EMS is nasty stuff.

Michael Clark
University of Iowa