Bierko received the nerve gas from Charles Logan, who intended to set the nerve gas off to kill Bierko and his men in order to send a message that the US had weapons of mass destruction. A scene was staged in which Ivan Erwich, one of Bierko's men, stole the nerve gas from a hostage situation. Erwich used one of the twenty canisters on a mall, which suffered minimal casualties due to CTU's intervention.
Upon realizing that James Nathanson, who was really working for Logan and Christopher Henderson, had betrayed him, Bierko killed Erwich for deviating from his plan, as he intended to use it against Moscow, and sent his men to kill Nathanson. He forced Logan to give him Russian President Suvarov's motorcade route by threatening to release nerve gas. When the attack failed, he decided to use the nerve gas on America.
First one of his men, Viktor Grigorin, tried to release the second canister in a hospital, but Curtis Manning killed Grigorin and put the canister in a contained area so no one was affected. Another of Bierko's men, Ostroff, released the third canister in CTU, although he was killed by Jack Bauer in the process. Much of CTU's staff, including Edgar Stiles and Lynn McGill, were killed in the attack, although Lynn sacrificed himself to flush out the nerve gas before it could enter the sealed areas.
Bierko attempted to release the remaining 17 canisters through a gas plant, but Jack Bauer and a CTU team arrived to stop him, incinerating the nerve gas and knocking Bierko unconscious. He was taken to CTU.
After regaining consciousness, Bierko was being transferred when he suddenly escaped. He had only used 16 canisters of nerve gas in his previous attack, saving the last one for a Russian submarine, which he used to kill all but one of its crew so he could take it over and launch the submarine's missiles. However, Jack and Henderson arrived and put a stop to his plans. Jack fought Bierko and killed him by breaking his neck.