In recent shop talk discussions Dave Anderson said;
>>The long term effects of breathing the zinc/lead conpounds on most
galvanized steels is death. The short term effects are simpler, figure
you've cut your bodies ability to absorb oxygen by about 50%,
permanently, every time you brath the fumes! Heavy metal poisoning is
for the most part irreversible, and that's what you're getting.<<
>> If you absolutely have to weld the material, grind the galvanizing
back to a where it does't even get warm!<<
NOT TRUE DAVE. I suppose the safest approach to anything you are
unfamiliar with is to avoid it, but disinformation should also be avoided.
Zinc doesn't even make the list of "toxic" elements found in cutting,
welding and brazing. The manganese and chrome fumes found when welding
some materials are considered toxic, zinc is not.
The following is from Volume 3 of the 8th edition of the AWS Handbook
(1996)
Zinc Safe Practices
Health Effects
Metal fume fever, more commonly called zinc chills, or brass founder’s
ague, may follow exposure to zinc fumes released during welding operations
on zinc-coated or zinc-containing metals including brazing rods. The chills
are caused by colloidal zinc oxide (0.3 to 0.4 micron diameter) penetrating
to the lungs. Larger sizes of zinc oxide adhere to the trachea and cause no
symptoms. This fever is an acute self-limiting condition without known
complications, after-effects, or chronic form. The illness begins a few
hours after exposure, or more frequently during the night, and may cause a
sweet taste in the mouth, dryness of the throat, coughing , fatigue,
yawning, weakness, head and body aches nausea, vomiting, chills, and fever
rarely exceeding 102 °F (39 °C). A second attack seldom occurs during
repeated exposure unless there has been an interval of several days between
exposure.
The American Conference of Government Industrial Hygienists publishes
threshold limit values for zinc oxide, which at this writing is set at 5
milligrams per cubic meter. The values are reviewed annually and are
subject to change.
Repeated exposure to moderate concentrations of zinc oxide in air has not
proved permanently harmful; however, exposure to concentrations high enough
to cause discomfort to welders or operators should be avoided.
VENTILATION
ACCORDING TO THE American standard ANSI/ASC Z49.1, if welding of materials
containing zinc is to be done in a confined space, ventilation must be
provided. If adequate ventilation cannot be provided, personnel who may be
exposed to fumes must be equipped with hose masks or be supplied
respirators approved by the U.S. Mine Safety and Health Administration
(MSHA) and by the National Institute for Occupational Safety and Health
(NIOSH).
I agree that you must be careful with lead, but even there, DEATH from lead
exposure is EXTREMELY rare.
Regards,
Bill (who has never been caught exposing himself) Ruof
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