Hans Suess was the first to point out that the burning of fossil fuels has a profound influence on carbon reservoirs. These fuels, obtained from the Earth's crust, are so ancient that they contain no C-14 at all. Indeed some of these materials are used as standards to enable the laboratories to monitor the background radiation. When the fuels are burned, their carbon is released into the atmosphere as carbon dioxide and certain other compounds. The annual release of this "dead" carbon amounts to approximately 5,000,000,000,000,000 kg as compared to the 7.5 kg of C-14 produced annually by cosmic radiation in the upper atmosphere.