He was a chairman of the Association of Sybiraks (Polish exiles to Siberia). Between 1939 and 1941, and 1944 and 1953, around 1.8 million Poles were deported to the Russian region of Siberia, resulting in 500 000 deaths. Ostensibly, the deportations occurred to those who had resisted the Soviet takeover of eastern Poland in 1939, assisted the Nazis during the Second World War, and who were members of the Polish Home Army—an anti-Communist resistance group during the war. A number of human rights groups in Poland protesting against the deportations that occurred, formed the Siberian Union in 1988 with Reiff as its leader.