-----Methylene chloride is a highly toxic solvent,  second only to carbon tetrachloride for it's leathality.  I speak from experience!

I used it for many years without any apparent ill effects.  One day,  (a hot summer's day as I remember), I opened a new drum of the stuff, (using full protective clothing),  and filled up the cleaning tank.  Within 48 hours,  I was nearly dead.  My skin broke out in big red blotches,  (Chloracne),  and my ears were literally dripping with serum.  I'd become sensitised to the stuff.  I'd reached my limit of tolerance.  The following weeks were hell.  It badly damaged my immume system,  as well as nearly destroying my liver and spleen.  I became so ill that I had to close my business.  Took me years to recover from the effects.  NOT nice!!