Tritium of tritium oxide introduced into upper layers of the oceans have been used in the years since then to measure the rate of mixing of the upper layers of the oceans with their lower levels. Tritium is an isotope of hydrogen, which allows it to readily bind to hydroxyl radicals, forming tritiated water (HTO), and to carbon atoms. Since tritium is a low energy beta emitter, it is not dangerous externally (its beta particles are unable to penetrate the skin), but it can be a radiation hazard when inhaled, ingested via food or water, or absorbed through the skin. HTO
Tritium 65 nuclear sites in the US. In one case, leaking water contained of tritium per litre, which is 375 times the EPA limit for drinking water. The US Nuclear Regulatory Commission states that in normal operation in 2003, 56 pressurized water reactors released of tritium (maximum: 2,080 Ci; minimum: 0.1 Ci; average: 725 Ci) and 24 boiling water reactors released (maximum: 174 Ci; minimum: 0 Ci; average: 27.7 Ci), in liquid effluents. According to the U.S. Environmental Protection Agency, self-illuminating exit signs improperly disposed in municipal landfills have been recently found out to contaminate waterways. The legal limits for tritium