I still don't have anything definitive as to whether these formaldehyde condensate sensitizers are appropriate or not, but I think you are misreading that MSDS that you linked to. The composition is 89-99% of CAS #41432-19-3, and 1-11% of "Sodium salts", there's no suggestion of any free formaldehyde in this sensitzer, as I'm reading it.

I really hope to find sources for these sensitizer compounds separate from the emulsions. It seems both cost- and resource-inefficient to have to purchase and then discard the emulsion.

2 more questions for mdm:

-- Can you buy just the sensitizer for Kiwo 225WR, or do you plan on discarding the emulsion?
-- Do you have a link to the MSDS for the sensitizer (Kiwo Sensitizer #14)? I'm curious to see whether it is the same as the ones (#1-#11) covered by the linked MSDS.

--Greg