The so-called "Montanmitbestimmungsgesetz" was legally consolidated on 21 May 1951 by the "Act on the Co-Determination of Workers in the Supervisory and Management Boards of Companies in the Coal, Iron and Steel Industries" in the Federal Republic of Germany by the votes of the opposition forces, helmed by the SPD. This act arranged that supervisory boards would be filled with representatives of the workers and the capital owners on equal terms. It entered into force on 7 June 1951.
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