In no case should a salt kiln be built and operated in
a small, tightly closed room. Even Varge structures
should be equipped with a suitable vent fan.

A variety of ehromium compounds, including potasesiwn
biehromate and chromite acid, are known to be poisonous.
Inhaled chromium compounds lead to acute pneumonia and
are definitely associated with some forms of lung
cancer. The most usual form of absorption is ingestion
and a fatal dose has been variously reported at from
one-half to five grams. In a case of acute poisoning
the patient suffers severe stomach pains, bloody diarrhea.
vomiting, kidney damage leading to retention of urine,
and usually dies in a state of complete collapse. Those
who survive this stage usually die within ten days as a
result of uremia. Even contact can be dangerous,
since chromium is irritating and destructive to all

cells in the body.

Cobalt is an important trace mineral in the human
system, but overdoses can cause an imbalance leading
to irritations and allergies.

‘opper 1s rarely involved in poisoning and only copper

auf and verdigr’e is considered dangerous. Neither
1s commonly used in ceramics, nor do they offer any
advantages over the more usual oxides and carbonates
and should, therefore, be avoided.

Copper sulfate can cause death in a matter of hours
in surprisingly small doses. It causes partial des-
truction of some vital organs.

Ferrie ehloride is not fatal, but can cause gastric
upset. It can also cause a permanent discoloration
if in contact with abraded skin.

Ferrous sulfate on the other hand can be fatal and
should be avoided,

Inhaled ¢ron chrenzte may lead to acute pneumonia and
has definitely been associated with some forms of
Tung cancer.

Lanthanwn Is little used in ceramics; it is quite rare

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