Zyklon B
Prior to World War II Degesch derived most of its Zyklon B profits from overseas sales, particularly in the United States, where it was produced under license by Roessler &amp; Hasslacher prior to 1931 and by American Cyanamid from 1931 to 1943. From 1929, the United States Public Health Service used Zyklon B to fumigate freight trains and clothes of Mexican immigrants entering the United States. Uses in Germany included delousing clothing (often using a portable sealed chamber invented by Degesch in the 1930s) and fumigating ships, warehouses, and trains. By 1943, sales of Zyklon B accounted for 65 percent of Degesch's sales revenue and 70 percent of its gross profits.