Fibrogenic potential of welding fumes

Abstract

A search of 3600 indexed pathology cases has disclosed pulmonary fibrosis in 29 welders. Scanning electron microscopy of biopsy material revealed macrophages laden with inorganic particulates which have characteristics compatible with welding aerosols. In order to establish a possible relationship between fibrotic reaction and welding-fume exposure, the fibrogenic potential fo some 11 different welding fumes and metallic aerosols, considered to be reference standard surrogates for the commonly used welding technologies and applications responsible for 70% of welders exposure, were screened using the Rat Peritoneal Macrophage in vitro bioassay. Only one class of fumes, that from the manual metal arc welding of stainless steel, showed distinct fibrogenic potential. This fume is, however, not common to more than four or five of the heretofore 90 cases of pulmonary fibrosis reported among welders. Thus, although insoluble Cr(VI) is probably the active fibrogen in stainless steel fumes, an etiological factor common to all fibrogenic welding exposures must be sought. It is tentatively proposed to be NO2, a potential experimental in vivo fibrogen copiously produced by certain welding processes and ubiquitous at low concentrations in the welding environment.

Role of metal oxide nanoparticles in histopathological changes observed in the lung of welders

“…To the best of our knowledge, only a very limited number of studies has been performed in welders, identifying the presence of nanoparticles [19-22]. However, although using the valuable combined (S)TEM/EDX analysis as developed by Abraham and colleagues [23-26], these studies present some major limitations, such as a small number of patient(s) [19,21], or a very specific exposure (aluminum factory, not representative of the general occupational exposure of welders) [20].…”

Pulmonary function abnormalities and airway irritation symptoms of metal fumes exposure on automobile spot welders

“…Severe inflammation and mild derangement of the alveolar wall was revealed in early stages of lung fibrosis, and less inflammation but marked derangement of the alveolar wall was observed in the middle or late stages. The interaction of several components of welding fumes including metal oxides and ozone, may lead to a complex pattern of damage to lung tissues after exceeding the clearance capacity of the bronchial and alveolar epithelium [Stern et al, 1983;Hicks et al, 1984;Muller and Grewe, 1992]. An increased inflammatory response initiates an over-load phenomenon especially after deposition of ultrafine particles of welding fumes [Donaldson et al, 1999].…”

Interstitial pulmonary fibrosis after severe exposure to welding fumes

“…Recently, interstitial pulmonary ®brosis (IPF) of welders with more serious clinical implications has been reported after long term, heavy exposure to welding fumes [Zober, 1981;Stern et al, 1983;Cox, 1984;Morgenroth and Verhagen-Schro Èter, 1984;Stanulla and Liebetrau, 1984;O È zdemir et al, 1995;Mu Èller and Verhoff, 2000]. Thus, histologically and clinically, benign welders siderosis is different from interstitial ®brosis of welders.…”