Vault 34 came with a large number of recreational amenities, including a swimming pool, as well as an overstocked armoury. However, this was at the expense of living space, leading to the facility becoming quickly overpopulated. Many residents soon began demanding access to the weapons in the armoury, but were denied by the Overseer. In the ensuing riots, a group of dwellers were able to escape, resulting in the entrance being fully sealed. Soon though, it emerged that radioactive gases had been leaking in due to infrastructure damage, and the vault door was now inoperable. With no means of escape, the remaining inhabitants were all either killed, or became feral ghouls.
Ironically, Vault 34 dweller Chris Haversham left the facility after incorrectly believing he had been turned into a ghoul due to his work maintaining the reactor. It was due to his vacancy that the reactor malfunctioned, and turned the vault into a radiation-filled nightmare.