This report documents laboratory and in-mine analyses of diesel exhaust pollutants carried out to assess the fate of potentially reactive species in a mine environment. Specifically, the concentration of stable compounds including carbon monoxide and carbon dioxide, and potentially reactive compounds including nitric oxide, nitrogen dioxide, sulfur dioxide, aldehydes, formaldehyde, acrolein, formic acid, odorants, particulates, soluble sulfates, and polynuclear aromatic hydrocarbons was determined. The concentration and mass emission rates of these compounds were measured in the laboratory under three engine speed and load conditions and with three exhaust control conditions; that is, none, catalyst, and water conditioner. Laboratory results confirm the relatively small effect of exhaust control devices on most pollutants under engine conditions of low speed and load. At higher engine speed and load, the catalyst is more effective in controlling many pollutants. The in-mine data indicate that during residence times, which are typical for miner-exhaust contact, most diesel exhaust pollutants do not decrease in concentration.