There are various types and sizes of Flood research facilities. Many were built on the Halo installations, including the Library structures, the Cold Storage facility below Installation 05's surface, and the Lockout facility, suspended in a mountainside. One facility was built in a Gas Mine in Threshold's atmosphere. Some facilities even have their own Monitors and unique types of Sentinels, such as Line Installation 1-4, a sprawling underground complex on an unnamed Moon. Installation 05's Cold Storage facility also had its own type of monitor, suspended to a ceiling. Installation 00 is known to possess at least one Flood research facility. Containment Protocols were often an integral part of the security in Flood research facilities.
It can also be assumed that other research facilities are still scattered throughout the universe, alone or on the interior of other Halo Rings. Unfortunately, the research facilities were unable to find a solution, other than finding that the Flood was susceptible to starvation. Thus, the Forerunners had to fire the Halo Array in order to eradicate the Flood threat. Now, these facilities have either been destroyed, or are uninhabited by sentient life. Installation 05 experienced a breach in its Flood research facilities around 290 years before the Battle of Installation 05, releasing the Flood in certain areas on the ring.
- Installation 00
- Installation 04
- Installation 05
- Unnamed Moon