Abstract: The present invention is a system for maintaining a controlled oxygen atmosphere within a transport container vessel, such as a bulk rail car through the use of permeable membrane technology. An oilless compressor is used in conjunction with the system so as not to subject the permeable membranes to the derogatory effects associated with the presence of oil within an air stream that circulates through the permeable membranes. The present system further includes an air-sampling system which is used to continuously measure the oxygen levels within the rail car so as to provide verification that the oxygen levels are maintained at 5% or less to kill insects, larvae, or eggs which may be within the bulk materials transported by the rail car.