Hoesch AG was an important steel and mining company with locations in the Ruhr area and Siegen. In 1871, Hoesch was founded by Leopold Hoesch. In 1938, Hoesch employed 30,000 people. In 1972, the prominent steel producer merged with the Dutch Hoogovens steel company to form Estel. It was formerly the largest employer in Dortmund. In 1982, the merger with Dutch company Estel was stopped by Detlev Karsten Rohwedder, and Hoesch became again an own company. In 1991, German competitor Krupp bought Hoesch.