Ten different kinds of dry food were fumigated with 10 g/m3 of 1-14C-Acrylonitrile (AN, 24 h, 20 degrees C). Residues of 0--19 mg/kg AN were found by Liquid-Scintillation-Spectrometry. The values become smaller as the density of the material increases. 30--70% of this agent are metabolised within two months.