The trust Interessen-Gemeinschaft Farbenindustrie AG (in short, I.G. Farben) was a conglomerate of German chemical and pharmaceutical companies, including Bayer, BASF, Hoechst and AGFA. It was established in 1925 and dissolved at the end of World War Two. After the war against Poland in late 1939, the I.G. Farben soon made plans to set up a new chemical plant in the vicinity of Auschwitz near the town of Monowitz for the synthesis of chemical raw materials out of coal. One of the intended final products was rubber made from a process called BUNA, which also became the name of this plant. This plant took ample advantage of the slave-labor force provided by the SS running the nearby Auschwitz Camp, which established a separate labor subcamp nearby (see the entry on Monowitz).
I.G. Farben was moreover a major shareholder of the DEGESCH pest-control company, which held the patent for Zyklon B, and developed and patented a standard fumigation gas chamber that was mass-produced during the war years.
Due to this entanglement with the slave-labor camp system and the German war effort, 23 of the top representatives of I.G. Farben were prosecuted by the U.S. occupational forces, who organized an entire trial at Nuremberg against them, the so-called “I.G. Farben Case” (NMT, Vols. 7f.). Ten of the defendants were acquitted, and 13 received prison sentences between 1½ and eight years (NMT, Vol. 8, pp. 1206-1209).