Working in an industry which was a major user of MC (tons) we found that it was nearly impossible to meet the OSHA MC standard without putting all employees in a major medical monitoring program and respirators. As a result, the industry abandoned the use of MC. Remember, the action level for the MC standard (the only OSHA standard with such) is 12.5 ppm which triggers major work and expense on the employers part. I doubt one could keep below that level consistently in an teaching lab. For simplicity, get rid of MC.
Lynn Knudtson
---------- Original Message ----------
From: drsamples**At_Symbol_Here**COMCAST.NET
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Benchtop Methylene Chloride Use in Undergraduate OChem labs
Date: Tue, 18 Nov 2014 04:54:24 +0000
Dear All,
I have a question for anyone involved in undergraduate Organic Chemistry labs.
Methylene chloride is listed as a recognized carcinogen in California, and it is a B2 probable human carcinogen. As you all know, it is a volatile liquid commonly used in undergraduate Organic Chemistry labs as the organic solvent in liquid-liquid extractions using a separatory funnel. As many OChem labs lack adequate fume hoods, many colleges do these extractions at the bench, and so are venting methylene chloride in the general laboratory. Generally, these are not microscale extractions, but are regular lab scale with a 250 or 500 mL sep funnel.
It is a volatile probable human carcinogen and thus I believe that it should be handled in the fume hood and the extraction should also be done in a fume hood. Do you agree or disagree? If you agree, have you been successful in changing how your department handles methylene chloride in undergrad labs, and if so, how did you successfully argue your case to handle it in fume hoods?
SIncerely,
Marjorie Samples
Chemistry Professor
Los Rios Community College District
California
