Fallout: 10 Most Evil Companies 

Mass Fusion was founded by Karl Oslow in 2043 and claimed to be the world's leading producer of clean nuclear energy, providing power to all of Massachusetts. As the name suggests, rather than standard nuclear reactors in our world that work through fission (the splitting of atoms), which produces toxic nuclear waste, Mass Fusion claimed that their reactors worked using the much cleaner, but more difficult method of nuclear fusion (the combining of atoms).

Unfortunately it was all a huge scam.

The "junction boxes" created and sold by Mass Fusion to generate power were all fission-based technology that were highly prone to radiation leaks but even as the populace reported nausea, hair loss, and burns from these devices, the company still claimed to be producing safe, clean energy.

They would hide the nuclear waste away in containment facilities or their dumping ground in rural Massachusetts and deny any allegations of wrongdoing.

It wasn't until the power armor fusion cell was created that Mass Fusion could finally live up to its name and provide actual fusion power but by then they had invested so much into fission infrastructure that it was impossible to fully switch over.