Activated carbons impregnated with compounds of chromium, Copper and silver (Cr-Cu-Ag) are widely used for removing toxic substances from air, mainly in respiratory protection for industrial and military applications. Toxicological and epidemiological studies have shown chromium (especially hexavalent Cr) to have carcinogenic properties. Hence, research has been launched to develop a new adsorption-catalytic complex without chromium, which is intended to replace the activated carbon-catalyst (Cr-Cu-Ag) system. In this work activated carbon obtained from plum stones as carrier and molybdenum, copper and silver salts as impregnates were Studied. The porous structure of the carbon carrier was investigated using low temperature nitrogen adsorption. Cyanogen chloride breakthrough dynamics was analyzed in order to characterize the protection properties. Studies on the substitution of chromium by non-carcinogenic metals will be continued. (c) 2008 Elsevier B.V. All rights reserved.