Transcript of narration in film shown at Nuremberg Trial in which Dachau gas chamber is described 

Document PS-2430: Nazi Concentration and Prisoner-of-War Camps: A Documentary Motion Picture, film shown at the Nuremberg Trial, 29 November 1945, IMT, XXX, p. 470:

"Dachau- factory of horrors. [ ... ] Hanging in orderly rows were the clothes of prisoners who had been suffocated in the lethal gas chamber. They had been persuaded to remove their clothing under the pretext of taking a shower for which towels and soap were provided. This is the Brausebad -- the showerbath. Inside the showerbath -- the gas vents. On the ceiling -- the dummy shower heads. In the engineers room -- the intake and outlet pipes. Push buttons to control inflow and outtake of gas. A hand-valve to regulate pressure. Cyanide powder was used to generate the lethal smoke. From the gas chamber, the bodies were removed to the crematory."

A 22-minute movie shown in the Museum at the Dachau Memorial Site contains some footage from the film shown at the Nuremberg trial. The "engineers room" is a narrow room behind the west wall of the gas chamber. Through a window on the outside of the building, one can see the "intake and outlet pipes" and the "hand-valve" shown in the film. There are similar pipes and a hand-wheel in the crematory room where the ovens are located. The photograph below was taken through the window of the "engineer's room" in the rear of the crematorium building in May 2003. According to information on display on the wall of the undressing room next to the gas chamber, the "push buttons" were stolen.

Pipe and hand-wheel in the "engineer's room at Dachau