Sentox nerve gas attack on CTU Los Angeles

During Day 5, CTU Los Angeles was infiltrated by a terrorist with a vial of Sentox nerve gas that killed 40% of the staff, permitted the escape of a key suspect, and caused Vice President Hal Gardner to order the absorption of CTU into Homeland Security.

Stolen nerve gas
The Department of Defense commissioned the production of some nerve gas called Sentox; it was made by the Sentox Project, part of Omicron International. Two years before Day 5, Christopher Henderson, a senior vice president at Omicron, had a role in killing the chief scientist Alan Burkette and at least two other scientists in apparent accidents. With the only non-conspirators who knew about the gas dead, Henderson and a small cabal of collaborators were able to steal twenty canisters of the Sentox for later use. The rest was decommissioned legitimately.

Government plot discovered
Walt Cummings had placed an undercover operative, Schaeffer, amongst Ivan Erwich's men. Schaeffer's duty was to reprogram the nerve gas canisters so that Cummings could remotely detonate them once it arrived at the terrorist base in Asia. Schaeffer was discovered under the suspicions of Erwich, and was subsequently killed.

Erwich obtained Cummings' mobile number through the listings on Schaeffer's mobile. He called Cummings and said that they now know about the double-cross. Since the ports were closed and the nerve gas had no way of leaving American soil, Erwich announced that, as punishment, their newly-acquired Sentox would be released in the United States. Erwich had a vial of the gas released at the Sunrise Hills Shopping Mall, killing 11 people.

After killing Erwich and regaining control of his operation, Vladimir Bierko also used it on a Los Angeles hospital, but the vial was discovered and subsequently removed from the hospital by Curtis Manning before it could release any gas.

Preparation for the gassing
Bierko decided to hit CTU Los Angeles as a third target, so as to cripple the United States' chances of stopping his final target, a Gas Company that would distribute the Sentox throughout millions of homes.

He employed the help of Ostroff, a terrorist who used Jenny McGill, the sister of CTU LA's Interim Director Lynn McGill, to steal Lynn's CTU key card. After falsely promising her boyfriend, Dwayne Thompkins, that he would buy the key card for $20,000, he killed Jenny McGill and Thompkins, and altered to key card to make it appear that he owned it, and was a worker at CTU.

The gassing


At 6:35pm, Ostroff logged in to CTU's server under Lynn McGill's name. He brought up the schematic of the ventilation system and put in a command to shut down the entire system inside of CTU. A message flashed on his screen confirming this. Working at her desk, Carrie Bendis noticed the disturbance on her screen and took it to Edgar Stiles, but Edgar told her to take a look at it herself. As she left, Edgar called back to her, but she did not reply.



Ostroff put the arming mechanism on the canister and starts to unscrew the door to the fan in the ventilation room. Carrie reached the ventilation room and saw the canister. She got out her phone to call someone, but Ostroff stabbed her in the neck before she could connect the call.

At 6:43pm, Ostroff put the canister inside the fan and set it to go off in 15 minutes. He took the timer with him. Meanwhile, Bill Buchanan informed Lynn McGill of the death of his sister. Lynn realized that their deaths could be related to the key card stolen by his sister and her boyfriend, and Buchanan asked Chloe O'Brian to check if McGill's key card had been used in the last half hour. Surprised, Chloe realized that it had and Buchanan called a lockdown.

At 6:52pm, Buchanan told Jack Bauer that they were still looking for the hostile and had locked down the exits. Jack told Audrey to get Kim down out of the Field Ops office. Edgar Stiles located Ostroff, and Buchanan sent Jack to find him. After noticing that Carrie was still missing, Edgar Stiles told Chloe that he was going to look for her. Meanwhile, Ostroff took out a guard and, stealing his radio, ran away.



Jack saw the killed guard in the hallway and realized that there was no walkie talkie. He sends a covert signal to Buchanan and Audrey, convincing Ostroff that he was in a different location. Convinced that he was in the clear, Ostroff headed towards a door. Jack crept up behind him and told him to freeze. Ostroff tried to fool Jack with a second gun but he was taken down before he could shoot Jack. Jack discovered the timer and realized that the nerve gas was in the system. Buchanan quickly called for a Code 6 evacuation throughout the building. Pandemonium ensues as the workers run from their desks.

From the ventilation room, Edgar called Chloe to find out what was going on, but Chloe told him to get out of the building. He called for Carrie, and stumbled upon her dead body. He turned to leave, missing the canister which had begun to release gas.



Audrey, Kim, and Barry Landes headed for the exit, but they noticed people starting to collapse in a different room. Chloe told to go to the Situation Room, which they could seal off, as Buchanan headed to the Director's Office, which was also secure. Jack told Rick Burke to send Christopher Henderson to clinic isolation, another secure room. The fourth safe room was Holding 4, where Lynn McGill was being kept.

Jack, Chloe, Audrey, Kim, and Barry ran into the Situation Room. Chloe sealed off the available rooms. As CTU workers around them died, the surviving people turned away in horror. Suddenly, Audrey noticed Edgar running back into the Bullpen. Chloe went to the glass, and Edgar called her name out and began to choke. The people in the situation room were speechless as he collapsed to the floor.

At 7:00pm, Curtis Manning called Buchanan from a car phone, and was alerted to the situation in CTU. He was bringing a CRT team back to CTU with him, but would not be back for another hour.

Chloe O'Brian discovered soon after that the seals protecting them from the gas were breaking. She deduced that terrorists added a corrosive agent to the gas that was eating through the seals. She told Buchanan they have less than a half an hour to fix the problem. Curtis Manning was on his way to CTU, but would not be there in time. Jack suggested using the air conditioning system, and learnt that there was a program that could active it, so Jack volunteered to go in.

At 7:25pm, Jack Bauer climbed through a false wall and made his way towards a separate room. After sufficiently sealing off the door he came through, ensuring no gas would get to anyone in the Situation Room, he set off through the gas, while holding his breath. However, he came to some steel bars that Chloe had not been informed of on her map of CTU due to a wrongly filed update. Chloe worked out that the only person close enough to the vent was Lynn, but once he left the room there would be nowhere for him to go to remove the Sentox from the air; he would effectively be going on a suicide mission. Lynn, thinking off all the trouble he caused, was able to reason with the guard and agreed to go down and deactivate the program.

The guard, Harry Swinton, made one final heartfelt phone call to his daughter, after which Lynn headed out. He was able to deactivate the program, and made it back to the room. After holding their breaths for as long as possible, McGill and Swinton both breathed in air and died instantly. Just before they died, Jack Bauer informed the men that their efforts were successful, and they were draining the gas from the systems. He also said that he would personally notify each of their families of their sacrifice.

By 7:53pm the air in CTU was safe to breathe again, and the people from the safe rooms were able to leave.

Known casualties
The following people were seen to have been killed as a result of the nerve gas.

Aftermath


The attack killed over 40% of CTU staff. In an early estimate, Bill Buchanan told Karen Hayes that he would need about 55 people to re-staff the building, making the CTU count between 135 and 140. However, this figure includes CTU operatives who were out in the field at the time of the attack, such as Curtis Manning and those off duty at the time. Almost all of the CTU agents in the building at the time were killed; the only survivors were a small handful who managed to make it to sealed rooms.

Tony Almeida also died after attempting to kill Christopher Henderson during the chaos caused by the attack.