The synthetic compound was developed by Massive Dynamic and stolen by Richard Steig. Steig was contacted by an unknown group of individuals to sell the contagion. The contagion was slipped into the insulin pen of Steig's twin brother, Morgan. While on Flight 627 from Germany to Boston, Steig injected himself with his pen, unknowingly setting the virus upon him and his fellow passengers. The entire airplane succumbed to the contagion, but not before the pilots put the plane on a special autopilot system that took the plane filled with corpses safely to JFK International in Boston. Following the Flight 627 event, Steig was contacted by John Scott, part of a special NSA task force investigating The Pattern, to not sell the contagion to anybody else. Scott was later infected with the contagion when pursuing a lead in the U-Case Storage facility. Steig, being chased by Scott and Olivia, detonated one of the storage containers, setting the toxin airbone and infecting John. Olivia investigated the contagion and discoverd a connection to the work of a Dr. Walter Bishop, who was locked in a mental institution. She contacted Bishop's son, Peter, to help remove him from the institution in the hopes that he would save Scott's life, who was later cured with the help of Walter and information provided by Steig.
John Scott became infected with the contagion while pursuing a lead. Olivia was able to get Walter freed from St. Claire's, but he was unable to cure John in time, who succumbed to the contagion.
Using elements from Walter's secret storage facility underneath Harvard, Peter was able to use the contagion for his own ends. The contagion was contained in attaché case similar to those that Observers carry around. Peter, using the Observer tech in his head, was able to calculate an exact scenario that would enable him to swap his case with an Observer's. When the Observer opened it, a smoke form of the contagion spread all over the room, causing the flesh of several Observers to melt. Peter, aware of possible futures, created this event as a diversion to allow the Resistance to gain access to William Bell's storage facilities and obtain two Beacons.
The toxin returned one last time with a slew of other biologiocal agents from past cases when the Resistance invaded an Observer facility to save Broyles. This biological attack killed many Observers and allowed the Reistance to get in and out of the facility unharmed.