Patent ID: 6977088

Claim:
A method for controlling pests in sufficiently gas-tight spaces, using gaseous phosphine (PH 3 ) as fumigant, comprising: delivering concentrated phosphine from a phosphine source, the phosphine source being a phosphine gas bottle having an exit valve; connecting the exit valve to a closed conduit, the conduit having a phosphine permeable dividing wall; interposing the phosphine permeable dividing wall within a stream of forced air; filling said closed conduit with concentrated phosphine delivered from the gas bottle so that said concentrated phosphine is permeating through the phosphine permeable dividing wall such that the so permeated phosphine is immediately diluted upon contact with the forced air stream at a point of introduction to below a concentration limit for self-ignition of phosphine-air mixtures, and introducing a resulting diluted phosphine-air mixture into the space to be fumigated.