WELDING FUMES

OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force.

CAS: None; Chemical Formula: Not available

OSHA formerly had no limit for exposure to welding fumes, which are defined as fumes that are generated by the manual metal arc or oxy-acetylene welding of iron, mild steel, or aluminum. The ACGIH has set an 8-hour TWA of 5 mg/m³ for these welding fumes, measured as total particulate in the welder’s breathing zone. OSHA proposed an 8-hour TWA of 5 mg/m³ for these fumes; this limit is established in the final rule. This limit applies to the total fume concentration generated during the welding of iron, mild steel, or aluminum; the fumes generated by the welding of stainless steel, cadmium, or lead-coated steel, or other metals such as copper, nickel, or chrome are considerably more toxic and shall be kept at or below the levels required by their respective PELs. Welding fumes consist of metallic oxides generated by the heating of metal being welded, the welding rod, or its coatings.

Although these types of welding generally produce fumes consisting of aluminum, iron, or zinc oxides, other toxic gases may also be produced in large amounts (Ferry and Ginther 1952/Ex. 1-900; Ferry 1954/Ex. 1-782; Silverman 1956/Ex. 1-1169; Homer and Mohr 1957/Ex. 1-787). The welding of iron metals may give off fumes of manganese, silicate, and various organic binders. Aluminum welding may generate fumes consisting of fluorine, arsenic, copper, silicon, and beryllium (NIOSH 1975h and American Welding Society 1974, both as cited in ACGIH 1986/Ex. 1-3, p. 634). Eighteen different substances, including fluoride, manganese, silicon, titanium, and sodium and potassium silicates, have been measured in the fumes resulting from the welding of mild steel (ACGIH 1986/Ex. 1-3, p. 634).

Excessive exposure to welding fume can cause a variety of disorders, most notably metal fume fever. It has been estimated that 30 to 40 percent of all welders have experienced metal fume fever at some time (Abraham 1983, in Environmental and Occupational Medicine, W.N. Rom, ed., p. 146). This disorder, which results from exposure to freshly formed metal fume, results in the appearance of delayed, flu-like symptoms, including dyspnea, coughing, pains in muscles and joints, fever, and chills. Recovery usually requires one or two days of time away from work. In addition to fume fever, exposure to welding fume may damage the small airways, causing interstitial pneumonia (Abraham 1983).

Several commenters, the American Iron and Steel Institute (Exs. 129, 188), the Abbott Laboratories (Tr. 9-155 to 9-156), and the American Welding Society (Ex. 3-860), were of the opinion that OSHA’s discussion of welding fumes in the NPRM was not clear with regard to whether the limit applied to exposure samples taken inside or outside of the welding helmet. OSHA wishes to clarify that welding fume is to be measured in the breathing zone of the welder; the specific details of the appropriate positioning of the sampler should be determined on the basis of guidance in the Field Operations Manual (OSHA 1984). This is consistent with a past OSH Review Commission decision Secretary of Labor v. Caterpillar Tractor (8 OSHRC 1043 (1979)).

NIOSH (Ex. 8-47) stated at the hearing that welding fumes should be designated as a carcinogen. This view was also endorsed by Dr. James Melium, of the New York State Department of Health (Tr. p. 11-104). In response to these commenters, OSHA notes that there are few data sufficient to establish a dose-response for the fumes. Accordingly, OSHA believes it would be premature to identify these fumes as potential occupational carcinogens.

OSHA concludes that a PEL for welding fumes is needed to protect workers involved in the welding of aluminum, iron, or mild steel from the significant risk of metal fume fever and respiratory irritation associated with the generation of welding fumes. In the final rule, OSHA is establishing a TWA of 5 mg/m³ for these particular types of welding fumes, measured as total particulate inside the welder’s breathing zone. The Agency finds that this limit will substantially reduce the significant risk of material health impairment to which manual metal arc or oxy-acetylene welders of iron, mild steel, or aluminum were previously exposed in the absence of any OSHA limit.