Fumigation with 2-aminobutane (2-AB) provides effective and convenient decay control for citrus fruits, but the temporary residue tolerance of 20 ppm can easily be exceeded. Factors found to control residues were the cultivar, concentration of 2-AB, temperature, duration of fumigation, and load (as a percentage of maximum capacity) in the fumigation chamber. The simplest procedure was to evaporate the entire charge of 2-AB as rapidly as possible. Residues in ‘Dancy’ tangerines and ‘Temples’ were higher than in oranges. Safe dosages for waxed fruit in poly bags and master cartons fumigated for 3 hr in full cabinets at various temperatures were (in ml/100 cu ft): 80 ml at 85° F, 110 ml at 70°, and in excess of 150 ml at 50° and below. Risk of exceeding tolerance at 40° and lower was minimal. Use of a chlorinated hydrocarbon, Quick Color, to eliminate explosion hazard had no consistent effect upon 2-AB residues.