Occupational exposure to airborne manganese (Mn) is currently determined using National Institute for Occupational Safety and Health (NIOSH) and Occupational Safety and Health Administration (OSHA) analytical methods for particulate not otherwise regulated. The Institute of Occupational Medicine (IOM) dual fraction sampler is capable of providing both inhalable and respirable portions of airborne particles by using only one sampling device. For this study, the IOM dual fraction sampler was compared with OSHA method ID-125G for determining occupational exposure to airborne Mn contaminant during Shielded Metal Arc Welding (SMAW), which was performed in a barge at a marine facility. An aluminum cyclone was used with a 25-mm Mixed Cellulose Ester (MCE) filter to sample respirable Mn contaminants. A 25-mm MCE filter was also used to sample total Mn contaminants. All monitoring was performed by area sampling. The aluminum cyclone readings, except one, were consistently higher than those of the IOM dual sampler (respirable) readings; statistically speaking, the aluminum cyclone showed significantly (p < 0.01) more exposure than did the IOM dual sampler (respirable). Therefore, the findings of this study suggest that the IOM dual sampler is not recommended as an alternative to the aluminum cyclone for the sampling of respirable Mn contaminants. However, the readings of conventional total particle sampler were not significantly different from those of the IOM dual sampler (inhalable). Inhalable and total are compared in this study and the results support the conversion factor of 1.0, which is for welding fume. Therefore, the IOM dual sampler can be used as an alternative method to conventional total particle sampler.