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Toxic Responses of the Lung
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
Inhalation of metallic iron or iron compounds causes siderosis. Siderosis is a relatively benign pneumoconiosis, characterized by large accumulations of inorganic iron containing macrophages in the lungs with minimal reactive fibrosis. In its pure form, the condition probably does not progress to true nodulation as seen with silicosis and is usually asymptomatic. It is known chiefly for the abnormal changes produced on chest radiographs. Siderosis is seen in its purest form in arc welders, oxyacetylene cutters, and silver finishers. During arc welding and oxyacetylene cutting, iron is melted and boiled by the heat of the arc or torch. The iron is emitted as particles of ferrous oxide which are immediately oxidized to ferric oxide and appear as blue-gray fumes. Prolonged inhalation of these fumes can lead to siderosis. Silver finishers use what is known as jeweler’s rough to polish their unfinished wares. The rouge is composed of iron oxide and is often applied with a buffer that generates a cloud of small iron and silver particles. When iron is inhaled in conjunction with other fibrogenic mineral dusts, pulmonary fibrosis results. This is referred to as mixed dust pneumoconiosis. Most of the affected miners have worked in the mines for more than 20 years. The symptoms and signs are relatively nonspecific. The miners often complain of shortness of breath, cough, and reddish-brown sputum. The shortness of breath is worst in miners who have massive fibrosis. The amount of fibrosis is in general related to the free silica content.
Metals I: Metals Preparation and Manufacturing
Published in Ronald Scott, of Industrial Hygiene, 2018
At high temperatures the metals of the working surface or welding rod vaporize. It is estimated that a small percentage of the mass of the electrode becomes vapor. Such metal vapors condense into respirable spherical particles called fumes, usually largely metal oxide in composition. Iron oxide fume is relatively low risk, although it can accumulate to produce a condition called siderosis. Siderosis does not involve fibrosis or other serious lung impairment. However, other metals either alloyed with iron in steel or as part of a coating on the object being welded also vaporize. Alloy metals of particular concern include chromium (stainless steel), beryllium (alloyed with copper), and manganese (welding rods). Harmful metals in coatings include lead (paints and solders), cadmium (anti-corrosion coatings), and zinc (galvanized steel). A number of fumes cause metal fume fever (Chapter 7). Studies on the rate of fume production are reviewed by Burgess (1995).
Toxicology
Published in Martin B., S.Z., of Industrial Hygiene, 2018
Inhalation of metallic iron or iron compounds causes siderosis. Siderosis is a relatively benign pneumoconiosis, characterized by large accumulations of inorganic iron-containing macrophages in the lungs with minimal reactive fibrosis. In its pure form, the condition probably does not progress to true nodulation as seen with silicosis and is usually asymptomatic. It is known chiefly for the abnormal changes produced on chest radiographs. Siderosis is seen in its purest form in arc welders, oxyacetylene cutters, and silver finishers. During arc welding and oxyacetylene cutting, iron is melted and boiled by the heat of the arc or torch. The iron is emitted as particles of ferrous oxide which are immediately oxidized to ferric oxide and appear as blue-gray fumes. Prolonged inhalation of these fumes can lead to siderosis. Silver finishers use what is known as jeweler’s rouge to polish their unfinished wares. The rouge is composed of iron oxide and is often applied with a buffer that generates a cloud of small iron and silver particles. When iron is inhaled in conjunction with other fibrogenic mineral dusts, pulmonary fibrosis results. This is referred to as mixed-dust pneumoconiosis. Most of the affected miners have worked in the mines for more than 20 years. The symptoms and signs are relatively nonspecific. The miners often complain of shortness of breath, cough, and reddish-brown sputum. The shortness of breath is worse in miners who have massive fibrosis. The amount of fibrosis is in general related to the free silica content.
Influence of welding fume metal composition on lung toxicity and tumor formation in experimental animal models
Published in Journal of Occupational and Environmental Hygiene, 2019
Patti C. Zeidler-Erdely, Lauryn M. Falcone, James M. Antonini
The most common metals present in generated welding fumes are listed in Table 1. Iron (Fe) is the primary metal in most welding fumes and usually composes >80% of MS fumes. Fume primarily made up of Fe has long been considered a nuisance dust with a small likelihood of causing chronic lung diseases. However, Fe has been shown to accumulate in the lungs of long-time welders and often causes a mostly benign lung condition known as siderosis.[10] Manganese (Mn), a known neurotoxicant, is a common component of most welding fumes as it improves metallurgical properties and acts as a deoxidizing agent to increase hardness and strength of the resultant weld.[11] Chromium (Cr) is common in SS welding fumes, existing in both Cr3+ and Cr6+ oxidation states.[12] The Cr3+ state cannot enter cells as readily and has low toxicity, whereas Cr6+ easily passes into cells, is highly toxic and is classified as a carcinogen.[13] The permissible exposure limit (PEL) of Cr was lowered from 52 to 5 µg/m3 in 2006 due to its harmful effects.[14] Nickel (Ni) also is a component of SS welding fume and classified as a human carcinogen.[15] Ni alloys are becoming increasingly popular in welding as a potential alternative to Cr-containing materials.[16]