Polyhalogenated compounds (PHCs) are any compounds with multiple substitutions of halogens. They are of particular interest and importance because halogens generally are highly reactive and also bioaccumulate in humans, and comprise a superset of which has many toxic and carcinogenic industrial chemicals as members.  PBDEs, PCBs, dioxins (PCDDs) and PFCs are all polyhalogenated compounds. They are generally non-miscible in organic solvents or water, but miscible in some hydrocarbons from which they often derive.