A field validation study of nitrogen-dioxide (10102440) personal passive samplers in an underground diesel haulage mine was conducted. The purpose of the study was to evaluate the precision, accuracy, and sensitivity of recently developed commercial passive nitrogen-dioxide samplers, the DuPont Pro-Tek, the MDA Palmes, and the MSA Vaporguard, versus that obtained with the standard NIOSH impinger method. All sampling was conducted in a trona mine at Green River, Wyoming. The samplers and impingers were mounted in a Latin square arrangement on top of a moving diesel personnel carrier, which served as the source of nitrogen-dioxide. Nitrogen- dioxide concentrations obtained in sampling did not represent ambient concentrations of nitrogen-dioxide in the mine air. Inter and intra/analyses of variance were examined to evaluate the significant differences of various treatments at the 0.05 significance level as well as to estimate accuracy, precision, and sensitivity of the samplers. Mean total nitrogen-dioxide concentrations of the sampling methods for 3 days of sampling were: NIOSH impinger 1.39 parts per million-hours (ppm-hr), MDA Palmes 1.45ppm-hr, MSA Vaporguard 0.79ppm-hr, and DuPont Pro-Tek 10.75ppm- hr. The corresponding coefficients of variation were 59.7, 62.1, 102.5, and 33.95 percent, respectively. Nitrogen-dioxide concentrations obtained by the DuPont Pro-Tek on all 3 days and on the combined 3 day comparisons were the only values to be significantly different from the impinger values. The authors suggest that the best accuracy is obtained with the NIOSH impinger, the MDA Palmes, and the MSA Vaporguard for nitrogen-dioxide concentrations of 0.3 to 2.93ppm-hr. They recommend that the study be repeated in another underground mine utilizing a direct reading physical instrument for nitrogen-dioxide as the baseline.