Hoover Dam Sub - Level 1C Hoover Dam Sub - Level 1C ( Classified ) is a secret pre - War research facility within Hoover Dam . Background . This was a top secret research laboratory in the pre - War days . Its main purpose was genetic experimentations for military exploitation ; i . e . making horrible abominations to not only terrorize the enemy , but also completely wreck ecosystems . The genetic mutations that would be created were specially designed to adapt to just about any ecology and take over , utterly wiping out anything else in its path . The reason why Hoover Dam was chosen was because there were several creatures in the area that seemed to be results of genetic mutations . Certain areas of the Hoover Dam Lake seemed higher in radioactive isotopes than other areas , which might have been the reason for the mutations . However , no matter the reason , it was considered a good place to start and further the process with a secret lab . Using similar technology that the Master eventually used for his twisted purposes ( he stumbled across the research in top secret computer archives ) , scientists made several specimens that grew to full size . However , shortly before the Great War started , a Chinese infiltration and sabotage team discovered the secret laboratory and tried to destroy Hoover Dam so the genetic work could never be used against them . Some of the Chinese stealth soldiers in Hei Gui stealth armor made it into S1C while others were planting bombs in the main generator rooms ( now called the Scum Pits ) . One of the bombs went off prematurely and alerted all of Hoover Dam , including the guards in S1C . Things become cloudy in the reports due to the chaos that ensued , but suffice it to say that the Chinese were defeated , the generators were heavily damaged , and S1C was compromised . During the heated battle in S1C , several genetically altered creatures escaped into the halls . The guard in the guard post was ordered to leave and seal the exit hatch if ever such an emergency happened , and the guard followed orders well . A couple of Chinese stealth soldiers and four scientists were trapped in S1C after the hatch was sealed , doomed to either die at the hands , or weapons , of the enemy , be consumed by the escaped genetic creatures , or just die of starvation . Layout . If the player ever makes it down here , he will find that the floor ' s integrity has been compromised . There is murky , green water that is about waist high all over the floor . The water comes from a broken wall and a hole in the floor . From that hole emerged mutated leeches and perhaps fish . Either way , these creatures turned out to be the food that has sustained the centaur s and floater s in SC1 . Once the player kills all the mutants , the player will have access to a great science lab and a top secret central computer that has some info on hydroponics , history , etc . Lastly , the player can find the dead Chinese stealth soldiers and use the materials from their stealth armor to make his own stealth armor . Appearances . It was to appear in " Van Buren " , the canceled " Fallout 3 " by Black Isle Studios . The Chinese sabotage mission is mentioned in a terminal entry cut from the " " " Fallout 3 " add - on .