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Engineering Controls Database

Welding Fumes and Fume Extraction Guns

Welding operations produce gaseous and aerosol by-products composed of a complex array of metals, metal oxides, and other chemical species volatilized from either the base metal, the welding electrode, or the flux material.

The effect of welding fumes and gases on a welder’s health can vary depending on such factors as the length and intensity of the exposure, and the specific toxic metals involved. Welding processes involving stainless steel, cadmium – or lead-coated steel, or metals such as nickel, chrome, zinc, and copper are particularly hazardous as the fumes produced are considerably more toxic than those encountered when welding mild steel. Mild steel consists mainly of iron, carbon, and small amounts of manganese, phosphorous, sulfur, and silicon, while stainless steel contains mainly iron, chromium, nickel, titanium, and manganese. The NIOSH criteria document identifies arsenic, beryllium, cadmium, chromium (IV), and nickel as potential human carcinogens that may be present in welding fumes.
Census data indicates that over 700,000 workers in the United States are involved in welding or allied processes. Animal and epidemiological studies suggest that welding is associated with a wide range of adverse health effects such as metal fume fever (with symptoms resembling the flu), pneumonitis, chronic bronchitis, and decrements in pulmonary function. A large body of evidence suggests that welders have a 40% increase in relative risk of developing lung cancer as a result of their work. Other cancers associated with welding include leukemia, cancer of the stomach, brain, nasal sinus, and pancreas. Welding processes are known to generate aerosols with a significant fraction in the nanometer size range. Recent research also has indicated that particles in the nanometer size range may have adverse health effects. Other health hazards during welding can include vision problems and dermatitis arising from ultraviolet radiation exposures, burns, and musculoskeletal stress from awkward working positions.
Fume-extraction guns were each attached to three-inch diameter ducts, dropped from the main header of the central exhaust system. Air captured by the fume extraction system gets filtered through a bag house and exhausted to the outside. The filters in the bag house were changed out every two to three weeks by a contractor.

Two types of fume-extraction guns were used. One gun, manufactured by Lincoln, incorporated the ventilation directly into the gun design. Lines for the shielding gas and exhausted air were encased in a large, single line leading from the gun. The second type of gun was a conventional, non-ventilated Lincoln model with a Tweco suction attachment connected to the gun nozzle. On this model, the shielding gas and exhausted air lines remained separate; the former led from the gun, the latter from the Tweco attachment.
214-11-A; 214-12-A; 214-13-A; 214-15-A;
arc welding
stainless steel