Other Contaminants

Paint & Coating Residues Isocyanates Solvents Phosgene Fluorides Arsenic Asbestos References

In welding operations, the worker often welds metals that have been painted or coated to prevent the surface from oxidation or other means of deterioration. When high heat is applied to these coated surfaces, volatile compounds and gases are emitted which are often hazardous. For more information, please visit our Paints and Coatings section.

See information on Isocyanates under our Paints & Coatings section.

See information on Solvents under our Paints & Coatings section.

Before welding metal surfaces, the worker often cleans or degreases the surface with hydrocarbon solvents which may contain compounds such as trichloroethylene, 1,1,1-trichloroethane (TCE), methylene chloride, and perchloroethylene (PCE). The vapors of these solvents are a concern in welding because heat and ultraviolet radiation from the arc will decompose the vapors and form highly toxic and irritating phosgene gas. Solvents used for degreasing purposes should be stored more than 200 feet from a welding arc. The odor of phosgene is recognized most often as the smell of fresh cut hay. Even a very small amount may be deadly, although early symptoms of exposure such as dizziness, chills, and cough, usually take 5 or 6 hours to appear.

In the process of arc welding, a welding electrode is used to fuse two metals together by conducting the current through the metal pieces. A type of welding known as flux-welding is employed to protect and clean the surface of the material and to prevent oxidation of base and filler materials. The flux may contain compounds with fluorides. Exposure to gaseous fluorides at low levels may irritate the eyes, nose and throat. In high concentrations, it may result in irritation of the pulmonary system leading to pulmonary edema.

Arsenic exposure in welding processes often occurs when welding ores contain the compound as a by-product (along with other elements such as copper, lead, cobalt, and gold). Heat based applications involving welding, smelting and refining of these ores can produce arsenic fumes. It is also found in alloys in combination with lead and copper in batteries, bearings, electrotype metal, ammunition, automobile body solder, and in corrosion resistance materials. The highly purified metal is useful in semiconductor applications. It is a known carcinogen.

Asbestos was widely used in manufacturing of numerous items prior to the 1980’s but has since been eradicated from many manufacturing processes. Welders in particular were exposed to high levels of asbestos due to the coating of the rods and other materials with compounds containing up to 15 percent asbestos. Asbestos exposure causes a lung cancer known as mesothelioma which affects the lung tissue. Although asbestos has been removed from most materials, workers who previously welded items containing asbestos 20-30 years ago are still at risk because it develops over many years.