Thanks for the compliment, Bob Richmond!  I'll try to answer 
tigergil's concerns.

The zinc salts in zinc formalin (any formulation) can enter the 
histotech's or pathologist's body only through ingestion (under any 
foreseeable circumstances).  They cannot be absorbed through intact 
skin.  Absorption certainly might occur through broken skin or mucous 
membranes, but the formaldehde would sting so badly that a reasonable 
person would not let it continue for long.  Inhalation of zinc salt 
dust during preparation of solutions would be highly unlikely if 
conventional lab hygiene is followed and the amounts being handled 
are lab scale.  In the manufacture of zinc fixatives on a commercial 
scale, we use approved particle masks for nuisance dusts, as well as 
gloves and goggles.

Zinc is an essential element, and will be found with sensitive assays 
in serum.  If test results are above normal, look for a metabolic 
disorder, some source of zinc via ingestion, or inhalation of zinc 
dust or welding fume.

Dick

-- 
Richard W. Dapson, Ph.D.
Anatech Ltd.
Battle Creek, MI
800-ANATECH (800-262-8324)
email@anatechltdusa.com
Web address:  anatechltdusa.com