Wood chips, torrefied wood chips, ground switchgrass, and wood pellets were tested for off-gas emissions during storage. Storage canisters with gas-collection ports were used to conduct experiments at room temperature of 20 �C and in a laboratory oven set at 40 �C. Commercially-produced wood pellets yielded the highest carbon monoxide (CO) emissions at both 20 and 40�C (1600 and 13,000 ppmv), whereas torrefied wood chips emitted the lowest of about <
200 and <
2000 ppmv. Carbon dioxide (CO<
sub>
2<
/sub>
) emissions from wood pellets were 3000 ppmv and 42,000 ppmv, whereas torrefied wood chips registered at about 2000 and 25,000 ppmv, at 20 and 40 �C at the end of 11 days of storage. CO emission factors (milligrams per kilogram of biomass) calculated were lowest for ground switchgrass and torrefied wood chips (2.68 and 4.86 mg/kg) whereas wood pellets had the highest CO of about 10.60 mg/kg, respectively, at 40 �C after 11 days of storage. In the case of CO<
sub>
2<
/sub>
, wood pellets recorded the lowest value of 55.46 mg/kg, whereas switchgrass recorded the highest value of 318.72 mg/kg. Finally, this study concludes that CO emission factor is highest for wood pellets, CO<
sub>
2<
/sub>
is highest for switchgrass and CH<
sub>
4<
/sub>
is negligible for all feedstocks except for wood pellets, which is about 0.374 mg/kg at the end of 11-day storage at 40 �C.