The fumigation colour reaction test referred to in Article 4(2)(c) shall be performed as follows:

• Samples of the entire sapwood thickness shall be taken with an increment borer from areas with intact bark at least one metre from the log ends and soaked in a freshly prepared (less than one day old) 1 % solution of 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) made with distilled water. Samples which show no red coloration after three days soaking are considered as having been adequately fumigated.