As a good point in our continuing discussion of "hazardous" materials, go
check that page, and look up "sodium chloride" which is common table salt.
The listing explains its toxicity and that personnel using it should wear
eye shields and protective clothing. News to me, but I guess if you are
handling carloads of the stuff and are constantly exposed to it, anything is
possible. If you do look up chems in the listing, check one salient factor:
the quantity requiring special labeling, etc. On thiourea, the quantity is
one pound (approx 500 grams). In the quantities photographers normally use,
this would be an enormous amount!
Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net