Isotopic substitution of18O was used in conjunction with secondary ion mass spectrometry to distinguish the source of gettered oxygen associated with damage produced in Si wafers by As ion implantation and by mechanical abrasion. It was found that oxygen was gettered from annealing ambients, exhibiting an enhanced diffusivity in the vicinity of the damaged layers at 600 °C. On the contrary, the oxygen originally dissolved in the wafers wasunaffectedby the damage, not being gettered by either type of damage and having the same diffusivity at that in undamaged Si crystals. These results are compared with published reports of16O analysis of similar experiments.