In this week's C&EN, a good overview and summary on the EPA's prohibitions on methylene chloride and their impact on academic groups (article by Krystal Vasquez):
On April 30, the US Environmental Protection Agency finalized a rule that prohibits nearly all uses of methylene chloride. To the relief of many academic chemists, the EPA carved out a number of exceptions to the ban, including the solvent’s use as a laboratory chemical.
But upon closer inspection of the regulation, researchers in the US are realizing that to keep using methylene chloride in their labs, they will need to conduct baseline monitoring and implement strict workplace safety measures—all in about a year.
At the time of the writing of the article, this EPA guidance document was not available, but now it is. It's thorough and clear, as the article notes, I think the practical effect will be the creation of a lot of poorly done EH&S compliance by overworked EH&S workers, grad students and PIs and a lot of regrettable substitution (get ready for a run on 1,2-dichloroethane). Maybe this will all work out for the better, but I don't think so.
1,2- Dichloroethane is already a Class 1 solvent so that is not the answer (DCM is Class 2 but had a low limit). Alternates are tricky because the halogenated solvents have such different properties to other solvents.
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