Sentox VX-1, or simply Sentox, was a nerve gas developed by Omicron International for the Department of Defense. When dispersed the gas was colorless and odorless but exceptionally deadly, with inhalation of even a trace amount capable of killing in a matter of seconds. The gas could be counteracted with the prompt administration of atropine however, and was not absorbed quickly enough through the skin for it to pose a danger to personnel with gas masks (or even just holding their breath).
A group of terrorists known as the Dawn Brigade working for Vladimir Bierko were sold the gas by White House Chief of Staff Walt Cummings, who was a pawn in a larger conspiracy directed by ex-CIA agent James Nathanson, Jack's former boss and mentor Christopher Henderson, U.S. President Charles Logan, a group of secretive businessmen led by a man named Graem (later revealed as Jack's brother in Day 6) with support from his and Jack's father Phillip Bauer and private military contractor Alan Wilson. Sentox was the primary terrorist weapon during Day 5.
Before Day 5
Retrieval from Ontario Airport
In the early hours of Day 5, a Russian separatist group called Dawn Brigade staged a terrorist takeover at the airport led by Anton Beresch. The situation was a diversion while another group of terrorists led by Ivan Erwich retrieved Chevensky's keycard and took the Sentox canisters out of the airport. Erwich then took the canisters to Schaeffer who was supposed to prepare them for their use. But Schaeffer, actually working for the American conspirators led by Graem Bauer, secretly re-programmed the trigger mechanism so the terrorists would themselves be gassed once they arrived at their base in central Asia. Erwich killed him upon finding that he tampered with the canisters. Afterward, with help from Sergei Voronov, Erwich came into contact with Jacob Rossler, who provided him with the tools to rearm the trigger mechanism.
Sunrise Hills Shopping Mall attack
Dawn Brigade terrorists Polakov and Komar partially deployed a single canister of Sentox into the ventilation system of the Sunrise Hills Shopping Mall, killing 11 people. Jack Bauer, who was at the time undercover with the alias Jacob Rossler, managed to stop the flow of nerve gas, killed Komar, and closed down the ventilation system. While pursuing the escaping terrorist, Jack rescued a small girl. Polakov remained under surveillance, and CTU followed him back to a repair garage owned by a civilian where Polakov's superior, Ivan Erwich, was operating. Erwich observed from a distance the arrival of the TAC team, ordered Polakov to kill himself, and then fled.
Tyler Memorial Hospital attack
Vladimir Bierko, now directing the Dawn Brigade's activities, sent Viktor Grigorin to deploy a single canister of Sentox near a ventilation system inlet at the Tyler Memorial Hospital. However, Curtis Manning and a TAC team intercepted and killed Viktor, and secured the canister in a containment unit seconds before the gas was released. This attack was actually a diversion, and it allowed Bierko time to attack his next, primary target.
CTU Los Angeles attack
- See the the main article here: Sentox nerve gas attack on CTU Los Angeles
Bierko's operative named Ostroff deployed a single canister of Sentox in CTU LA's ventilation system using Lynn McGill's keycard, sold to him for $20,000 by Dwayne Thompkins (whom Ostroff later killed, along with his girlfriend, and Lynn McGill's sister, Jenny). Jack killed Ostroff, but not quickly enough to locate and secure the canister. However, Jack found the timing relay switch and PDA, and after reporting the danger, Bill Buchanan ordered an evacuation (Code 6) and asked Chloe O'Brian which rooms they could seal off from the gas.
After being informed of the locations (The upper offices, Situation Room, Holding Room 4 and Clinic Isolation), Bill Buchanan went to the CTU Director's Office, Lynn McGill & Harry Swinton remained in Holding Room 4, and Tony Almeida, Agent Burke and Christopher Henderson were stuck in Clinic Isolation while Jack, Chloe, Audrey , Kim and other employees and visitors went to the Situation Room. After these rooms had been sealed, a female CTU worker asked to be let into the Situation Room, but was refused entry by Jack because of the danger to those the Situation Room; she died as they watched helplessly. After this, Edgar Stiles came running out onto the main floor. From inside, Chloe heard him say her name; it was his last word. He, too, died in front of the agents in the room.
Approximately twenty minutes later, Chloe discovered that the Sentox had been mixed with a corrosive agent, which would gradually break down the seals in the safe zones. Lynn was able to undo the modifications Ostroff had made to the ventilation system, which gradually cleared the gas from CTU, through both he and Harry were fatally exposed to the gas in the process.
Wilshire Gas Company attack
Vladimir Bierko, Mikhail, and a team of other terrorists infiltrated the Wilshire Gas Company, killed a security guard and two workers, and forced Sam to assist them in deploying 16 canisters of Sentox in the main distribution tank. They lowered the pressure so the nerve gas would not be neutralized, and CTU discovered their location by monitoring the decreasing pressure level there. Jack, Curtis, and two other CTU field agents stormed the gas plant to prevent the gas from infiltrating natural gas lines in thousands of Los Angeles homes and buildings. A shootout ensued: two field agents and Bierko's men were killed, Bierko himself was captured, and the Sentox was incinerated when Jack ignited the natural gas it was mixed with. Only minimal, harmless traces were found in the pipes leading away from the plant.
The Natalia attack
Vladimir Bierko and his last team infiltrated the Russian submarine Natalia, and deployed a single canister of Sentox near the entrace of the submarine and killed all but one of the crewmen, in an attempt to access and use the sub's Scorpion Land Attack missiles and use them against civilian targets. Jack Bauer, Christopher Henderson, and Agent McCullough infiltrated the submarine with the help of Tim Rooney after the gas had been neutralised. They secured the missiles and killed all of the terrorists, including Bierko himself.
Background information and notes
- For his death in the gas attack, Edgar Stiles received a silent clock.
- Out of most of the murders seen being committed by Vladimir Bierko and Polakov, a majority of them were by the Sentox nerve gas detonations.