Technical tecnazene (2,3,5,6-tetrachloronitrobenzene), is an odourless, crystalline solid that is used in its formulated form as a fungicide and as a sprout inhibitor on stored potatoes. Gas chromatography with electron capture detection is the preferred method for its determination. Exposure of the general population is expected to be mainly through residues in food. The residues reported are below the FAO/W11O maximum residue levels. No cases of accidental or occupational overexposure have been reported.