Laboratory 5

One of the many Alchemical Laboratories that operate within the influence and city limits of Central City, Lab 5 is located on the outskirts of town. Though Laboratory 5 was said to have shut down, the Elric Brothers' investigation reveals that the building's gate is guarded by an armed soldier at all times, the high wall surrounding it is set with razor wire and alarmed booby traps and that the interior is kept lit just enough to accommodate passage through the facilities. Additionally, Lab 5's heinous secrets are guarded by the Slicer Brothers and Barry the Chopper. The building is also rigged with explosives, so it can detonate at any time.

It is also located next to Central Prison, from which "ingredients" were taken from among the death row inmates. After Edward makes it into the heart of Lab 5 and encounters the Slicer Brothers, Lust and Envy, the building's explosives are activated, destroying all evidence of the immoral experimentation that had gone on within. It is later revealed that all the scientists involved with Laboratory 5 had disappeared mysteriously just days before its destruction and implied that the they had been used as ingredients for a Philosopher's Stone themselves. Laboratory 5 was also said to have been under the jurisdiction of Brigadier General Basque Grand, who had already been murdered by Scar by the time the Elrics discovered it.

It is later revealed that Laboratory 5 is part of a Five-Point Transmutation Circle around Central City which includes the other four labs and is also an inner layer of the Nationwide Transmutation Circle.

2003 Anime
In the 2003 anime, Lab 5 is also home to numerous chimeras who assist in guarding the facility and Human Chimeras being held for experimentation. Additionally, the lab serves as an alchemical prison and stasis field for the rogue Homunculus Greed, who has been housed within its lower levels for roughly a hundred and thirty years.