This paper describes the risk factors for the development of posttraumatic stress reactions in children after a technological disaster in Ghislenghien, Belgium in 2004. Children were assessed at five months (T1, N=128) and at fourteen months (T2, N=69). At T1 and T2 respectively, 7 % and 4 % of the responding children showed severe posttraumatic stress reactions. Of those who showed posttraumatic stress reactions at T1, 60%recovered from these symptoms at T2. One child developed severe posttraumatic stress reactions between T1 and T2.