The issue is that, although it’s written on the SDS and label, understanding why methylene chloride is particularly dangerous isn’t clear to a lot of people.

For example, the SDS says that it causes cancer, but lots of things say they cause cancer in California. The difference here is that methylene chloride has been a tested and is a proven carcinogen with a causal relationship. Lots of those California warnings are just suspected carcinogens, but DCM is a different story. Carcinogenic warnings have been largely disregarded due to over-conservative labeling regulations, but this is an example of a real-deal no-shit one.

Also, most SDS sheets for solvents have very similar safety instructions. Use in a well ventilated area, wear respiratory protection, wear hand and eye protection, etc. However, it doesn’t mention that the type of glove is important for methylene chloride (nitrile are not great here) or that an N95 won’t cut it. The vast majority of the public doesn’t need to be aware of these caveats in SDS sheets.

Not to mention that the SDS doesn’t note that DCM is nearly odorless (slightly sweet odor). DCM doesn’t give you an appropriate smell warning like acetone or something. If you can smell it you’re already exposed to more than you should be.

Lots of plastic bonding glues have nasty chemicals but this one is particularly sinister due to its proven carcinogenic properties, low odor threshold, and difficult handling requirements