Welding Processes

Welding is the process by which pieces of metals or thermoplastics are combined or joined by applying heat, pressure, or a combination of both. It is one of the oldest industrial processes in practice today. The earliest examples of welded metals date back to the Bronze and Iron Ages. Welding processes occur in approximately 2% of industrialized working populations; and workers who perform welding tasks are at risk for exposure to various fumes and gases including carbon monoxide, nitrogen dioxide, ozone; also, metal fumes from zinc, cadmium, hexavalent chromium, and mercury among others at dangerous levels. Studies show that welders are at risk for developing lung-related ailments such as bronchitis, pulmonary infections such as pneumonia, and lung cancer.

There are many types of welding processes but the most commonly practiced are Shielded Metal Arc Welding (SMAW) and Gas Metal Arc Welding (GMAW), which comprise roughly 70% of all welding methods. The most commonly welded metals are carbon steel, stainless steel, and aluminum. Exposure to hazardous fumes and gases depend on the welding method and materials involved, the composition of the welding rod (electrode), filler and base metals, paints and coatings being welded, and area ventilation.

Although personal protective equipment and controls are mandated by OSHA and NIOSH for welding processes, welders remain at risk for occupationally-induced lung cancer and other health-related conditions.