In this work we use dislocation loops to monitor the interstitial injection during the oxidation of silicon at low temperatures (850-950 degrees C). The interstitials captured by the loops are measured using transmission electron microscopy. The number of Si atoms released after oxidation was calculated from the difference in the total amount of atoms stored in the loops between oxidizing and inert ambient. A model has been developed for the estimation of the average interstitial supersaturation within the dislocation loops layer under injection conditions. Combining our experimental results and the model we estimated the average interstitial supersaturation at the surface.