The concentration of six different gases produced by the detonation of four explosives was measured in a dry underground metal mine during actual mining operations. The four explosives included one semigelatin dynamite, one gelatin dynamite, and two water gel explosives. A standard drill pattern was used to detonate the explosives as a full-face round in the drift. The gases released by the explosion were trapped in the drift. The concentration of the gases in the test chamber were measured by direct readout instruments. The average volume of each gas per pound of explosives detonated in the following ranges, in cubic feet per pound: no, 0.04 to 0.14; NO2, 0.03 to 0.10; Co, 0.08 to 0.45; So2, 0.0001 To 0.0006; Nh3, 0.003 to 0.027; and co2, 1.82 to 7.02.