[en] Purpose: To settle and eliminate iodine at high efficiency by using hydrophobic substance as the carriers for silver nitrate or silver to thereby prevent steams from adsorbing on the carriers. Method: Radioactive iodine-containing gases are passed through a layer filled with hydrophobic porous carriers carrying silver nitrate or silver to settle and eliminate the radioactive iodine. Since the silver nitrate or silver is carried on the carriers of hydrophobic porous substances such as polytetrafluoroethylene, styrene-divinylbenzene copolymer, steams in the gases contacting thereto are scarcely condensed even in the saturated condition on the carriers. The radioactive iodine in the gases are catalytically reacted with silver nitrate or silver directly into silver iodide and settled and eliminated. (Seki, T.)