Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted an in-depth study of the gas metal arc welding operations at an agricultural and construction equipment manufacturer. The company produces heavy machinery such as trenchers, tractors, hay balers, tree-handling equipment, and directional boring systems. Approximately 475 welders are employed in seven independently operated plants located at the site. In the past, worker exposures to welding fumes were controlled through a combination of general and local exhaust ventilation. Recently, plant management changed from conventional power sources to pulsed inverter power sources for their welding operations. Research has shown that under laboratory conditions gas metal arc welding with pulsed arc can reduce fume generation. This fume reduction is due to the ability of pulsed current to transfer metal droplets from the wire, through the arc, to the work piece, with minimum heat. The purpose of this study was to evaluate whether the welding fumes generated during pulsed arc welding in the production environment are indeed significantly less than that of conventional arc welding, given similar process parameters.