(Capcom's primary storyline)
This outbreak, unlike other t-viral outbreaks was not caused by the Umbrella Corporation, but by the Organization. A special forces team under the command of ex-Umbrella employee Albert Wesker infiltrated the island's military training centre and released the virus. This covert attack was to draw the military trainers' attention towards the Zombies and Irregular Mutants while they participated in their actual mission: locating and capturing Alexia Ashford and/or a sample of her experimental T-Veronica virus..
The outbreak quickly infected much of the island's population. Though some managed to escape to the Antarctic Base via the island's cargo planes, the virus followed them and infested that facility as well.
The island was seemingly abandoned by Wesker's forces after the initial spread of the virus. The prisoners held by Umbrella on the island as well as the Training Facility's staff were all infected by the time Rodrigo Juan Raval released Claire from her cell. The virus also reanimated corpse in the small graveyard outiside of the prison. Overall only Claire, Steve, Rodrigo, Wesker, and Alfred Ashford were the only survivors. Initially it was believed that Alexia was also a survivor present on the island, but this was later proven false. All areas of the island were infested with Zombies and B.O.W.s, including the Prison, Military Training Center, the Ashford Palace, Ashfords' Residence, and even the airport. Any survivors used planes to get off the island. However, the infection was carried by one of the passengers (according to D.I.J's diary) which eventually led to the outbreak in the Antarctic.
Eventually, the situation was made much worse by Alfred, who began releasing B.O.W.s such as Bandersnatches and the facility's very own Tyrant to try and kill Claire and Steve. His rationality began to go off the deep end once his "sister" was revealed to be nothing more than himself impersonating her.
Alfred set off the island's self-destruct system and abandoned the island, going to the Antarctic Base.
Following the partial destruction of the island, Chris Redfield arrived in search of Claire. Right after his arrival, he witnesses the death of [[Rodrigo]] after he is ingested and then regurgitated by the Gulp Worm. Beyond the B.O.W.s already present on the island, he faced Enhanced Hunters released by Wesker, who was still present on the island. Both of them would eventually departed in pursuit of Alexia and Claire. After these events the fate of the island remains unclear, since no further record is made in known Umbrella documents or archives.
The events of both this and the subsequent Antarctic outbreak were later relayed by Claire to Leon Scott Kennedy, a rookie ex-Raccoon City Police Department cop she had befriended during the Raccoon City Destruction Incident. He would later divulge these events to Jack Krauser, a SOCOM operative, during a mission in 2002 in South America, when explaining his prior experiences about B.O.W.s.
Ultimately, the event was also detailed in several reports, which also included references to Wesker. These reports later resulted in the then recently discharged Krauser to try to search him out after the events of the aforementioned mission, Operation Javier, resulted in his arm being severely damaged.