My reading of the proposed regulation is that “use as a laboratory chemical” would include use as a solvent in research laboratories. Their rationale for not banning it was essentially that laboratories have fume hoods, and are therefore
probably able to use methylene chloride safely. I happen to agree with this logic, which is why I agree with Jennifer that requiring a supplied air respirator as the only form of is overkill, as is the requirement that “initial” exposure monitoring be performed
every five years irrespective of use of engineering controls.
I’m also surprised by the PEL that they chose. We all know the inadequacies of OSHA’s existing PELs, but there are other regulatory/advisory bodies out there we can look to whose approaches are generally more protective. The Cal/OSHA
PEL is 25 ppm, the ACGIH’s TLV is 50 ppm, and the EU’s OEL is 100 ppm. It’s not impossible that all three could have set values an order of magnitude or two too high, but it doesn’t seem very likely.
Chris
________________________________
Christopher M. Kolodziej, Ph.D.
Chemical Hygiene Officer
UCLA Environment, Health & Safety
| Chemical Safety
-----Original Message-----
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Ralph Stuart
Sent: Tuesday, May 9, 2023 10:56 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] EPA ban of methylene chloride
> Moral is that we need to be careful about making things worse with overly simplistic thinking.
The unspoken question in this statement is worse for who? I don’t believe that EPA is aiming its regulations at lab uses of methylene chloride, but if the rule leads to greener chemistries being explored, that could lead to unexpected
discoveries of value in chemical processes.
As your note suggests alternatives need to be evaluated carefully, but I have seen successful substitutions for a variety of chemicals driven by compliance concerns. I have also seen unfortunate substitutions occur for the same reason.
But I don’t think that the moral is as simple as the one you proposed.
- Ralph
Ralph Stuart, CIH, CCHO
ralph**At_Symbol_Here**rstuartcih.org
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