Welding involves joining metal together by applying heat and often a filler metal. The welding process is essential in many manufacturing, construction and maintenance sectors and therefore is an area of concern for OSHA. The filler metal, base material, coatings and/or gases utilized in welding can emit various forms of particulate into the environment, often referred to as welding fume. Welding fume has the potential to be hazardous, depending on the fume’s composition and concentration.
There are numerous elements found in welding fume, with hexavalent chromium and zinc causing the most concern for welders because of its commonality in welding environments. Hexavalent chromium is present when welding on stainless steel or using stainless steel filler metals. OSHA has mandated that prolonged exposure to fumes containing hexavalent chromium be kept below an 8-hour time-weighted average (TWA) Permissible Exposure Limit (PEL) of 5 µg/m3 (micrograms per cubic meter of air) with an Action Level of 2.5 µg/m3. Zinc, the other common element in welding environments, is a byproduct of welding steel with a galvanized coating and has an 8-hour TWA PEL of 5 mg/m3 (milligrams per cubic meter of air).