(Capcom's primary storyline)
Incineration Disposal Plant P-12A was a biological waste processing facility located in the industrial zone in north-eastern Raccoon City. Owned and operated by Umbrella USA, the facility was used for the safe disposal of biowaste left over from experiments at NEST, a nearby laboratory complex, and not only used the latest breakthroughs in biowaste disposal, but also provided employees with antiretroviral drugs to prevent infection due to their high-risk duties. The facility was disguised as an abandoned warehouse near a scrapyard, and may even have been refurbished from one. This facade allowed it in theory to keep out spies, though guards were kept on stand-by to kill urban explorers happening upon their work, or otherwise sending them to NEST for experimentation. A subway station privately owned by the company was located nearby, which was to allow for the transport of personnel, though where it lay is unknown. During the 1998 Raccoon City Destruction Incident, Plant P-12A was the site of a battle between a Delta Force unit and a group of Tyrants shortly before it was destroyed by an experimental thermobaric weapon.
Umbrella's need for a dedicated biowaste disposal facility came about in the 1990s with the increasing number of experiments performed at NEST which, while prioritising research on the Golgotha Virus, also performed research on t-Virus strains. Due to the enormous use of test subjects, Umbrella began construction of a separate site which could take over functions, with biohazardous material likely being transported via Umbrella's private subway. The facility used a variety of gases and medicines to destroy evidence of B.O.W. research. In the event material was present which could not be destroyed in the treatment pool, an incinerator was used as a means of drawing power.
The factory was constructed in 1998, and was already crewed by its staff for at least nineteen days when building was finished on 14 May. The primary provider of waste was the NEST, which it was connected to by subway. Its chief researcher Dr. William Birkin started producing more waste than the P-12A plant could process. Only a month after waste processing began, the machinery was being used far more frequently than they were designed for and their condition began to degrade. The machinery finally began to fall apart in mid-July, resulting in a dramatic loss of functionality. The t-Virus began to mutate into new strains with the bodies left undisposed; the staff soon found the t-Virus antibodies they were provided with had no effect on the new strain and began transforming into Zombies in late July. The bodies of several researchers were subsequently taken to the processing room to be disposed of if the machinery was repaired. With the facility's computer programmed to shut the factory down in the event of a quarantine, the uninfected staff were sealed in with no hope for escape, allowing Dr. Birkin to quietly abandon them with justification.
The facility was left abandoned until late September 1998 when the US Army's Delta Force arrived at the facility. Having entered Umbrella's private subway line with the intent of infiltrating NEST, the unit was unfamiliar with the tunnels and found themselves several miles away. UBCS commander Colonel Sergei Vladimir ordered a helicopter to drop five T-103 Tyrants to deny them access to sensitive materials. The T-103s and the Delta Force unit mutually destroyed one another, partly with the aid of the US Army's experimental anti-B.O.W. rail cannon, "Sword of Paracelsus".
On October 1, the facility was visited by a number of people seeking a means of escape. UBCS Sergeant Nikolai Zinoviev stole a helicopter from the scrap yard to rendezvous with Umbrella contacts. Jill fought Umbrella Europe's Nemesis-T Type B.O.W. in the facility's possessing room and managed to power the machinery to begin another treatment. This however, only succeeded in destroying the Tyrant shell and force the Nemesis parasite to mutate in the virally-enriched fluid. It was finally destroyed soon after by Jill Valentine with the revolver of a dead Delta Force operative after the Demon Sword incapacitated him. Minutes later, the facility was destroyed along with the rest of the city following the execution of the Sterilization Operation.
- In the English localizations, this facility is otherwise known as the "P-12A Incinerator Facility" or "P-12A Waste Disposal Facility". It is referred to in Japanese as "disused plant", which is read as "dead factory" in English.
- Though no subway is seen in-game, it is confirmed in a 1999 Famitsu interview with Yasuhisa Kawamura