Initially, the Swiss "national cooperative for the storage of radioactive wastes" (NAGRA) was looking for an ultimate disposal site in deep granite layers covered with sediments as a second safety barrier. Since such a site was not found, the dumping of HLW (high-level radioactive waste) should now be possible in sedimentary rock (“Opalinuston”, a special form of clay). The NAGRA selected the area of Benken in canton Zurich, directly at the German border near for this purpose. There, a 105-125 m-thick layer of Opalinuston was found in a depth of between 400 and 900 meters. Up to 500 cubic meters of highly radioactive waste and 15.000 cubic meters of long-living, medium-level waste might be dumped there, starting from 2020. Until then the radiating waste from the five swiss nuclear power plants is supposed to be temporarily stored near Würenlingen, which is also located at the Rhine. "Who can judge, how safe the underground of Benken will be for a hundred thousand years?", the federation for environment and nature protection (BUND) criticises the plans of the Swiss atomic industry. "What will happen if the Opalinuston dries and splits because of the heat emission of the radioactive waste?" asks Axel Mayer of the BUND´s regional association “Southern Upper Rhine”. A leaky repository at the Rheinfall would not only endanger the local groundwater, but also the Rhine as a source of drinking water for millions of Europeans. The entire area of Switzerland is geologically in motion according to environmental experts. The African mainland slides against the European one, the unfolding of the Alps will continue and the Rhine rift will widen. "Due to the geological conditions Switzerland is completely unsuitable for such a repository", says BUND-activist Mayer. Resistance against the planned storage site in Benken has already built up on both sides of the Rhine. The Swiss Federal Council will not come to a decision before the end of of 2004.