Another claim made by Holocaust deniers is that there were no specially-constructed vents in the gas chambers through which Zyklon B could be released [REF].
Cremation in the open at the Reinhard death camps (Treblinka, Sobibor and Belzec) was discussed at Nuremberg on the 7th April 1946 by Georg Konrad Morgen, SS judge and lawyer who investigated crimes committed in Nazi concentration camps.