Operation Reinhard
Wirth worked at scaling up the Action T4 program, in which people with disabilities were murdered by gassing or lethal injection, and then at scaling up Operation Reinhard, by developing extermination camps for the purpose of mass murder. Wirth served as Inspector of all Operation Reinhard camps. He was the first Commandant of Bełżec extermination camp. He was later killed by Yugoslav Partisans in Hrpelje-Kozina near Trieste.