E715 was a POW camp for British prisoners which was administered and guarded by soldiers from Wehrmacht because it was a subcamp of Stalag VIII-B camp. However, as it was attached to the Monowitz concentration camp (codenamed Buna after the synthetic rubber it made) which was one of the 28 sub-camps under the control of Auschwitz III, the SS had effective control. E715 was next to the I.G. Farben chemical plant just a few hundred meters away from the entrance to Monowitz.
