Zone 3 is a large factory, presumably operated by Enoch, its Guardian. It is described as haven in which every Elsen may have a job and feel productive. Sugar is produced here, which is the fifth element - a secret element created by Enoch, observed to have an addicting effect on the Elsen.
It is known that the process by which sugar is obtained involves burning the bodies of deceased Elsen. Sugar is described by one of the Elsen as "the most important element", stating that without sugar, people would be "unable to bear reality, and they would go mad." Another Elsen is observed mumbling to himself in contemplation of opening the sugar pipes and letting it spill forth. He feels temptation in this way, but dare not risk suffering the consequences.
In the factory, there are many posters which encourage a calm and compliant work environment. One of such posters instructs the Elsen that if they are polite to any passing spectres, they will not be harmed. This is obviously witnessed to be false later in the Zone, when The Batter observes a spectre harming and killing a lone Elsen.
The third, and last add-on, Epsilon, can be found in this Zone either in the eastern dorms of the cafeteria room or in the room leading to Enoch's office.