Occupational Safety and Health Administration OSHA

General Hazard: Respiratory Irritation and Systemic Poisoning

Respiratory irritation and systemic poisoning from exposure to toxic fumes and particles during welding and cutting operations.
Hazard Description

A broad range of pyrolysis products are produced during welding operations. Hazardous vapors are produced from the heating of base metals in steel and aluminum alloys. Other pyrolysis products are released from metal coatings and finishes, flux, and welding rods. Exposures and controls needed increase greatly when welding is performed in confined spaces.

Potential hazards exist for:

  • Oxides of Nitrogen, Nitrogen Dioxide
  • Ozone
  • Cadmium. Contained in cadmium-coated steel and may also be present as a minor component in welding materials. Cadmium causes acute and chronic lung disease and chronic systemic disease.
  • Iron Oxides. May cause siderosis.
  • Zinc Oxides. Occur from zinc-enriched paints and galvanized steel. Zinc exposure is the usual cause of metal fume fever.
  • Chromium. May be present in some paints. Chromium is released in significant concentrations when welding stainless steels and is a probable carcinogen when in its hexavalent form.1
  • Manganese. Contained in welding rods.
  • For additional information, see OSHA's Welding, Cutting, and Brazing Safety and Health Topics Page.
  • Siderosis from iron dust inhalation has been found after prolonged exposure. Metal fever (also called "zinc fever," "fume fever," "Monday fever," "foundry fever," and "welders' ague") is sometimes found. Symptoms last for about twenty-four hours and include fever, nausea, and coughing.
  • As well as chronic systemic poisoning, welding on cadmium-coated steel can cause an acute intoxication without warning symptoms.
  • Mechanical ventilation is required during welding and cutting where (1) there is less than 10,000 cubic feet of space per welder, or (2) where the overhead height is less than 16 feet, as required in 29 CFR 1910.252(c)(2).
  • 29 CFR 1910.252(c)(5) through (10) covers welding operations where workers may be exposed to fluorine compounds, zinc, lead, beryllium, cadmium, and mercury.
  • Welding in confined spaces should be a rare occurrence during the fabrication of structural metal products, but when it occurs, additional requirements are imposed. Where ventilation is insufficient to preclude hazardous exposures, airline respirators or hose masks must be used, as required by 29 CFR 1910.252(c)(4).

1 Effects of Welding on Health, III. American Welding Society: Miami, 1983.

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