The location of a carbon and two hydrogen atoms in a alpha-Fe divacancy is analysed using a tight-binding theoretical method. Calculations were performed using a Fe-124 cluster. Absorption sites for the impurities near the divacancy correspond to local energy minima configurations. Fe atoms first neighbours to H atoms weaken their metallic bonds. The decohesion of Fe-Fe bonds could be associated to H embrittlement. The C atoms almost do not affect the Fe-Fe bond strength. Fe-C and Fe-H bonds are formed mainly with Fe 4s orbitals. There is no bonding between C and H atoms but some H-H interaction is observed. (c) 2005 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.