Blockführer was a paramilitary title of the SS, specific to the Totenkopfverbande (Concentration Camp Service). An SS-Blockführer was typically in charge of a prisoner barracks of between two to three Concentration Camp

Nazi concentration camps

Nazi Germany maintained concentration camps throughout the territories it controlled. The first Nazi concentration camps set up in Germany were greatly expanded after the Reichstag fire of 1933, and were intended to hold political prisoners and opponents of the regime...

 prisoners; in larger camps, this number could be as a high as 1000. The Blockführer was in charge of daily attendance, supervising daily work details, and distributing rations to prisoners. Assisting in this case were several prisoner trustees, known as Kapo

Kapo (concentration camp)

A kapo was a prisoner who worked inside German Nazi concentration camps during World War II in any of certain lower administrative positions. The official Nazi word was Funktionshäftling, or "prisoner functionary", but the Nazis commonly referred to them as kapos.- Etymology :The origin of "kapo"...

s. The position of Blockführer was usually held by an SS-soldier holding the rank of either Unterscharführer

Unterscharführer

Unterscharführer was a paramilitary rank of the Nazi Party used by the Schutzstaffel between 1934 and 1945. The SS rank was created after the Night of the Long Knives...

 or Scharführer

Scharführer

Scharführer was a Nazi Party title that was used by several paramilitary organizations from 1925 to 1945. Translated as “Squad Leader”, the title of Scharführer can trace its origins to the First World War, where a Scharführer was often a Sergeant or Corporal who commanded special action or shock...

.

In the Nazi Death Camps, the task of actually gassing prisoners with Zyklon B

Zyklon B

Zyklon B was the trade name of a cyanide-based pesticide infamous for its use by Nazi Germany to kill human beings in gas chambers of extermination camps during the Holocaust. The "B" designation indicates one of two types of Zyklon...

 was held by an SS non-commissioned officer known as a Blockführer. A similar title, known as Blockleiter

Blockleiter

Blockleiter was a Nazi Party political rank which existed between the years of 1930 and 1945. The Blockleiter was the lowest political official of the NSDAP, responsible for the political supervision of a neighborhood or city block and formed the link between the NSDAP and the general...

 also existed as a Nazi Party political rank.

Source

• Zentner, Christian & Bedürftig, Friedemann, The Encyclopedia of the Third Reich, (Macmillan), New York (1991)