The purpose of this study was to develop environmental release factors for metal welding operations in order to more accurately estimate emissions of selected metals as required under the Superfund Amendments and Reauthorization Act (SARA), Title III, Section 313. These release factors are needed by industry and the Office of Toxic Substances to estimate the quantity of metals emissions entering the environment. These environmental release factors were determined by measuring emissions during carefully controlled welded operations. The emission tests were conducted at the Lincoln Electric Company in Cleveland, Ohio, in conjunction with the National Electrical Manufacturers Association (NEMA). Lincoln Electric furnished the fume testing apparatus, welders, and welding rods.