Mixed stage cultures of Tyrophagus putrescentiae, Acarus siro, Periplaneta americana, Sitophilus oryzae, Oryzaephilus mercator, Tribolium castaneum, Lasioderma serricorne, Dermestes maculatus, Ptinus tectus, Ephestia cautella, Lepinotus patruelis and Liposcelis bostrychophilus, also larvae of Anthrenus verbasci, Trogoderma granarium and the wood borer Anobium punctatum, were exposed to atmospheres containing 60per thousand CO₂ for periods between one and 56 days at temperatures between 15 and 25°C. Relative humidity was 75per thousand. Fourteen days exposure at 15°C controlled all species except S. oryzae which required 28 days. Exposure for four days or less at 23°C controlled all species except L. bostrychophilus which required 8 days, and S. oryzae which needed 14 days (at 25°C). At 35°C four days or less controlled all species except T. putrescentiae, T. granarium and A. punctatum which required 14 days. These results are in broad agreement with published data where available. Carbon dioxide fumigation of infested stored commodities requires the maintenance of relatively high concentrations of CO₂ for relatively long periods. The heat retaining version of a special fumigation enclosure ( bubble ) is capable of holding high concentrations of CO₂, which by means of a thermostatically controlled recirculating heater can be heated to reduce the exposure period required for disinfestation of commodities.