Banagrass, a fast growing tropical grass with potential use as a feedstock for energy, fuel, and chemical production, was tested in a pilot-scale steam exploder equipped with a gas sampling system. Known quantities of argon injected into the reactor with process steam sewed as a trace gas and permitted quantification of biomass-derived gases. A total of 77 tests were performed over a uniform matrix of temperature and log(10) Reaction Ordinate, Ro=t exp (T-100)/14.75 where t is time in minutes and T is temperature in degree Celsius. The main carbon-containing species in the biomass-derived gases was CO2. Gas-phase carbon ranged from 0.5% to 2.4%, averaging 1.1% of feedstock carbon. Gas phase carbon increased with increasing severity, reaching a maximum at similar to 205 degrees C.