A nuclear, biological, chemical (NBC) canister was indigenously developed using active carbon impregnated with ammoniacal salts of copper (II), chromium (VI) and silver (I),and high efficiency particulate aerosol filter media. The NBC canister was evaluated against carbon tetra chloride (CCl_4) vapours, which were used as a simulant for persistent chemical warfare agents under dynamic conditions for testing breakthrough times of canisters of gas masks in the National Approval Test of Respirators. The effects of CCl_4 concentration, test flow rate, temperature, and relative humidity (RH) on the breakthrough time of the NBC canister against CCl_4 vapour were also studied. The impregnated carbon that filled the NBC canister was characterized for surface area and pore volume by N_2 adsorption-desorption isotherm at liquid nitrogen temperature. The study clearly indicated that the NBC canister provides adequate protection against CCl_4 vapours. The breakthrough time decreased with the increase of the CCl_4 concentration and flow rate. The variation in temperature and RH did not significantly affect the breakthrough behaviour of the NBC canister at high vapour concentration of CCl_4, whereas the breakthrough time of the NBC canister was reduced by an increase of RH at low CCl_4 vapour concentration.