Process Name

Welding

Description

The most commonly used welding processes are shielded metal arc (stick welding), metal inert gas (MIG welding), tungsten inert gas (TIG welding), oxy-fuel welding, and submerged welding. In stick welding, the shielding gas evolves from the flux coating of the electrode; in MIG and TIG welding, the inert gas is provided directly. The most commonly welded metals are mild steel, stainless steel, and aluminum. Stick welding on stainless steel produces higher hexavalent chromium exposure than MIG or TIG welding. Welders are at increased risk for the following acute conditions: pulmonary edema from welding in a confined space; photokeratitis of the eyes from UV exposure; and metal fume fever from welding copper or zinc coated metals. [Burgess, p. 168-9] Welding fume comes mainly from the filler metal and flux (if used); the contribution of the parent metal is relatively minor. Coatings on the surface of the parent metal may be significant inhalation hazards. [Hendrick, p. 470] Stick welding is the preferred method in the construction industry; it is less sensitive to the wind than MIG or TIG welding. [PMID: 17963139] Advantages of stick welding: welding in all positions; inexpensive; and can be performed by unskilled welders. [PMID: 12645092] Welding fume is classified by IARC as a possible human carcinogen. Based on six case-control studies, IARC determined in 2012 that, "There is sufficient evidence in humans for the carcinogenicity of welding. Current evidence establishes a causal association for ocular melanoma although it is not possible without a full review of welding to attribute the occurrence of ocular melanoma to UV radiation specifically." [IARC Monograph 100D] The welder may be exposed to dangerous concentrations of cadmium fume, phosgene, nitrogen dioxide, and ozone. Each of these four agents can cause delayed pulmonary edema. See OSHA website: http://www.osha.gov/SLTC/weldingcuttingbrazing/index.html.

Category

Weld

Related Information in Haz-Map
Agents

Hazardous agents associated with this process: