Water Well Journal

August 2016

Water Well Journal

Issue link: http://read.dmtmag.com/i/705618

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Page 33 of 71

W elding produces various contaminants at a sufficient rate to cause both short- and long-term health effects if not properly controlled. A comprehensive review of epidemiological studies of welders indicates a large number of welders experience some type of respiratory illness—bronchitis, airway irritation, lung function changes, and a possible increase in the incidence of lung cancer. More than 500,000 workers are employed in welding and related occupations in the United States according to the Bu- reau of Labor Statistics. Another 200,000 welders or more are retired. That adds up to a potential pool of more than 700,000 people who have been exposed to welding fumes. Pulmonary infections may also increase in terms of sever- ity, duration, and frequency among welders following their exposure to welding. Studies have also associated chronic exposure to manganese with a risk for Parkinson's disease. The best way for a company to reduce the potential of large settlements is to provide documented evidence the company is progressively making efforts in controlling exposure to weld- ing fumes and gases. The first step is to understand the potential health effects and recognize the factors affecting a welder's potential expo- sure to welding fumes and gases. Health Effects Welding fumes are small particles that are formed when the vaporized metal rapidly condenses in the air. Typically too small to be seen by the naked eye, the particles collectively form a visible plume. The health effects associated with metal fumes depend on the specific metals present in the fumes. These effects may range from short-term illnesses such as metal fume fever (with flulike symptoms) to long-term lung damage or neuro- logical disorders such as lung cancer and Parkinson's disease. Gases are also generated from welding, which may include carbon monoxide, ozone, and nitrogen oxides. Carbon monoxide is an odorless, colorless gas that may be formed by the incomplete combustion of the electrode cover- ing or flux and by the use of carbon dioxide as a shielding gas. Overexposure to carbon monoxide hinders the body's red blood cells from carrying sufficient oxygen to other tissues within the body, which subsequently results in asphyxiation. Welding does not normally generate carbon monoxide at high enough levels to be a concern. However, high levels of carbon monoxide may potentially accumulate when welding or air arc gouging in confined spaces. Also, there's the poten- tial of an oxygen-deficient atmosphere if welding inside a confined or enclosed space if an inert gas (such as argon) is used as the shielding gas. Ozone, nitrogen dioxide, and nitric oxide are produced by the interaction of ultraviolet light from the welding arc with the surrounding air. These compounds are irritating to the eyes, nose, and throat. High exposures can also cause fluid in the lungs and other long-term pulmonary illnesses. If the metal has been de- greased with a chlorinated solvent, other airborne gases (phos- gene, hydrogen chloride, chlorine gas) may be produced. These gases generally cause irritation to the eyes, nose, and respiratory system—and symptoms may be delayed. Common Welding Processes The type of welding process is directly related to the amount of fumes and gases generated. And so, it is important to have a basic understanding of the welding process in order to assess the risk of exposure. Shielded metal arc welding (SMAW) Also called stick welding, and commonly used for carbon steel welding and low alloy welding. In SMAW, the electrode is held manually, and the electric arc flows between the elec- trode and the base metal. The electrode is covered with a flux material, which provides a shielding gas for the weld to help minimize impurities. The electrode is consumed in the process, and the filler metal contributes to the weld. SMAW can produce high levels of metal fumes and fluoride exposure; however, stick welding is considered to have little potential for generating ozone, nitric oxide, and nitrogen dioxide. Gas metal arc welding (GMAW) Sometimes referred to as metal inert gas (MIG) welding, typically used for most types of metal and is faster than shielded metal arc welding. This process involves the flow of SAFETY MATTERS EXPOSURE TO WELDING FUMES AND GASES It's critical workers are protected against dangers of welding. SAFETY continues on page 34 JEROME E. SPEAR waterwelljournal.com 32 August 2016 WWJ The first step is to understand the potential health effects and recognize the factors affecting a welder's potential exposure to welding fumes and gases.

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