Nearly 2,000 German enterprises got involved in cooperation with Auschwitz. Numerous firms employed prisoners directly, on the spot, or in the sub‑camps, or sub‑let prisoners to their sub‑contractors; for example IG Farben “loaned” prisoners to at least 81 construction companies. Other companies delivered various products and supplies to the camp, undertook specialist renovation and construction works. Among them were large, well‑known firms like Osram, which supplied light bulbs for the lamps mounted on the camp fence or Siemens, which equipped the camp with various kinds of electrical devices. However, the majority were small retailers, wholesalers, drug stores, and shops operating in Upper and Lower Silesia.

Some companies were aware of what was going on in Auschwitz. There can be no doubt that the management of Topf und Söhne, which designed and supplied parts for the crematoria furnaces, was aware. The same is true of Tesch und Stabenow GmbH, which supplied Zyklon B, and the owners and employees of the companies involved in building the crematoria and gas chambers—Josef Kluge of Gliwice, Schlesische Industriebau Lenz u. Co. of Wrocław, Huta Hoch u. Tiefbau AG of  Katowice, and many others.

(Mini dictionary of terms from the history of Auschwitz)