A welder spends the day welding galvanized steel without ventilation and that night has chills, fever and aching muscles. What is the likely cause?
- Arc eye from ultraviolet radiation
- Metal fume fever from zinc oxide fume
- Heat stroke from the leather jacket
- Oxygen deficiency from argon gas
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B. Metal fume fever from zinc oxide fume
The zinc coating on galvanized steel vaporizes and forms zinc oxide fume; breathing it causes flu-like metal fume fever some hours later. The coating should be removed from the weld area and ventilation or respiratory protection used.
Reference: Welding safety: metal fume fever
Which hazardous substance is a particular concern in the fume from welding stainless steel?
- Zinc oxide
- Carbon dioxide
- Acetone vapor
- Hexavalent chromium
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D. Hexavalent chromium
Stainless steel contains chromium, and arc welding converts some of it to hexavalent chromium, a carcinogen with a low permitted exposure limit. Zinc oxide comes from galvanized coatings, not stainless.
Reference: Welding safety: hexavalent chromium in stainless welding fume
Why must parts cleaned with chlorinated solvents be completely dry, and the solvent kept away, before arc welding?
- Arc heat turns the vapor into harmless steam and salt
- Arc radiation breaks the vapor down into toxic phosgene
- The solvent film makes the arc too stable to control
- The solvent vapor makes the shielding gas flow too high
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B. Arc radiation breaks the vapor down into toxic phosgene
Ultraviolet radiation and heat from the arc decompose chlorinated hydrocarbon vapors (some degreasers and brake cleaners) into highly toxic gases, including phosgene. Even vapors drifting in from a nearby degreasing tank can be affected.
Reference: Welding safety: chlorinated solvents and arc radiation