In our Emergency Department, different sections of the ED are designated by different colors and each color is covered by one nurse. So there's a nurse for Orange, Red, Purple, etc.
An ED attending I was chatting with recently was telling me that there used to also be a section for Black. He said that lasted exactly one day, until the first time they called over the intercom, "Will the Black nurse please come to the nurse's station?"
Apparently, that made everyone very uncomfortable.