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Mass Fusion is the leader in the safe handling and disposal of radioactive waste.Fallout 4 Vault Dweller's Survival Guide Collector's Edition p.281

The Mass Fusion containment shed is a location in the Commonwealth in 2287. Before the Great War, it was the site of Mass Fusion's illegal nuclear waste disposal operation.


This warehouse for Mass Fusion's stored nuclear waste that was waiting to be disposed at a site near Lake Cochituate. After the war, the waste remains, leaving the area moderately irradiated and a natural refuge for feral ghouls.[1]

This was a hazardous workplace before the war for multiple reasons. On September 13, 2077 an employee named Lester died after tripping behind the forklift. In response corporate forced the facility to post a multitude of work safety posters. Their main concern wasn't that an employee had died, it was that it set their accident free day number back.[2] This had a horrible effect on the morale of the other employees, such as the dead employee's supervisor. Already a dejected individual, the supervisor truly had their hope drained from them. After years of dealing with the corrupt, self-absorbed fools, the supervisor developed a seething hatred for their employment and fellow managers.[3]

On October 22, 2077, a hazardous material inspector stopped in unannounced to check their operation. The supervisor informed the security chief, Mr. Feld, who told them that if he caught on to their illegal dumping scheme, they would need to kill him, which they did. They disposed of the remains in the pipe they were using to dispose of the nuclear waste into Lake Quannapowitt.[4] Already complicit in the illegal dumping, they were now also complicit in a conspiracy to commit murder, to which they expressed remorse.[5]


The interior is a warehouse storing many barrels of radioactive material, as such irradiating the entire building. It contains glowing radroaches and feral ghouls. In the top floor room is the supervisor's terminal, containing personal entries and the lock control for the security gate at the rear of the first floor.

Past the security gate, and next to the conveyor belt, is a floor hatch leading to the subterranean reactor room. The hatch is located behind some barrels next to the conveyor belt, and directly opposite the generator with the fusion core. In the center of the reactor room is the reactor with a circuit breaker switch affixed to the farthest side.

Notable loot

  • A fusion core on the generator behind the security gate.
  • A Vault-Tec lunchbox is located in the subterranean area on the desk next to a broken terminal.


  • The generator in the subterranean chamber is powering the automated radio alarm signal, picked up by radio tower 3SM-U81. Deactivating the generator will stop the signal broadcast.
  • Although the automated radio alarm must be deactivated by the generator at the reactor level, there is a ham radio hidden beyond the wall to the west. It can be seen and used only through console command tcl.


The Mass Fusion containment shed appears only in Fallout 4.

Behind the scenes

On the southwest corner of the rooftop is the corpse of a raider lying supine in front of a kneeling, deactivated synth. The setup alludes to the "Tears in rain" scene at the end of the film Blade Runner.


  • PCPC Flipping the circuit breaker in the sub-level will sometimes fail to disable the automated radio alarm. A workaround is to return to radio tower 3SM-U81 and re-extend the satellites, then return to the containment shed to flip the breaker again. The warning klaxons in the sub-level can de-sync with the radio signal if the klaxons are turned off before resetting the radio tower.[verified]
  • PCPC Playstation 4Playstation 4 Xbox OneXbox One Both of the ghouls that are hidden in the radioactive waste in the middle of the warehouse can not be looted directly. A workaround is to order one's companion to search the corpses. On PC, one can open the developer's console, click on the ghoul, and enter the command openactorcontainer 1 as another workaround.[verified]



  1. Fallout 4 Vault Dweller's Survival Guide Collector's Edition p. 281: "[2.13] MASS FUSION CONTAINMENT SHED
    Mass Fusion is the leader in the safe handling and disposal of radioactive waste. Except here the place is overrun with Feral Ghouls and spilled barrels. Check the outside balcony for a cooler (Novice). Inspect the supervisor’s terminal (Novice) to unlock the security door. Check the secure area for a toolbox (Novice) and a gate to a steamer trunk."
    (Fallout 4 Vault Dweller's Survival Guide Map)
  2. Mass Fusion containment shed terminal entries; supervisor's terminal, 7/13
  3. Mass Fusion containment shed terminal entries; supervisor's terminal, 8/04
  4. The site as it is in Fallout 4, the pipe flows north
  5. Mass Fusion containment shed terminal entries; supervisor's terminal, 8/22