Extermination units functioned as pest control services on the Outer Rim world of Elphrona throughout the High Republic Era. In the year 232 BBY, a certain property on Elphrona began to suffer problems because of a chromant infestation. Jedi Master Loden Greatstorm, stationed at the Jedi outpost on Elphrona, intended to assist the property owners himself, rather than having them request aid from an extermination unit; however, Jedi Knight Indeera Stokes wondered if his intervention was truly required. In the end, the Jedi were unable to resolve the property's chromant problem, as they had to leave to carry out a rescue operation in another location on Elphrona.
The existence of extermination units was first revealed in Light of the Jedi, a novel from 2021 penned by Charles Soule, which formed part of Phase I of the larger Star Wars: The High Republic cross-media initiative.