User blog comment:Darkman 4/Zombies 100% confirmed for Black Ops/@comment-1957587-20101001014328/@comment-66.169.101.69-20101001041525

So that'll probably be one of the maps... Just a speculation, but they might've tried to use element 115 in a nuclear reaction, so either something went wrong and the occupants of the facility got infected, or the place went through meltdown and infected a large amount of people.