In order to exterminate insects, fumigants need long enough time with specific concentration rate (C x T product) to affect them. In order to comprehensively control all development phases of insects, necessary exposure time for Methyl Bromide must be from 48 hours or longer while 120 hours are minimum required time for Aluminium Phosphide because the nature of Phosphine is slowly affect insects and AlP itself is not a chemical for exterminating insects but Phosphine (PH3) is released from the following chemical reaction:

AlP + 3H2O = PH3 + Al(OH)3