At a 130°C temperature, which can be regarded as conservatively representing the temperature in the annulus of a pressurized water reactor (PWR) during the first phase of a design basis loss-of-coolant accident (LOCA), no significant difference was found in the retention of 131I loaded as elemental iodine by various fresh and aged commercial activated carbons (at the same aging time). In all cases, the 131I passing through deep beds of carbon (25 cm equivalent to a residence time of 0.5 s) was in a nonelemental form. At 180°C, which can be excluded in a LOCA, similar results were obtained. With aged carbons, however, elemental 131I also passed through equivalent carbon beds at this temperature. It is concluded that a minimum retention of 99.99% for elemental radioiodine, as required by new guidelines in the Federal Republic of Germany for PWR annulus exhaust air filters in a LOCA, can be achieved as well with various commercial activated carbons.