Twenty grams of carbon dioxide were automatically metered into each of 1, 530 sealed 18.9-liter metal cans filled with wheat. Samples were tested to determine whether an atmosphere previously established as lethal to insects would be achieved and maintained. Concentrations of 42.1% or more carbon dioxide were maintained in the cans for 15 days and gradually decreased for 105 days more. The cost of the treatment was less than 1 cent per can or 1/20 cent per liter. In sealed cans that were not treat the respiration of the wheat did not reduce the oxygen in the cans to a concentration lethal to insects during the 120-day test period.