Tritium Leaks at Nuclear Power Plants Contaminate Groundwater

The nuclear industry has recently come under fire for leaking tritium - a radioactive isotope of hydrogen - into the groundwater of areas surrounding nuclear plants. Leaks have been reported at the Braidwood, Byron, and Dresden reactors in Illinois, the Palo Verde reactors in Arizona, and the Indian Point nuclear plant near New York City. Even worse, nuclear energy companies have kept the discoveries of these leaks from the public, sometimes for several years. Tritium is a byproduct of nuclear generation and can enter the body through ingestion, absorption or inhalation. Long-term exposure can increase the risk of cancer, birth defects and genetic damage. In June 2005, the most recent study from National Academies of Science (NAS) reaffirmed that there is no level of radiation exposure that is harmless or beneficial, and that even the smallest dose of ionizing radiation is capable of contributing to the development of cancer. Tritium takes about 250 years to decay to negligible levels, and is very difficult to remove from water.

Recent History of Tritium Leaks


The Braidwood Generating Station in Illinois, 60 miles southwest of Chicago and run by Exelon, has recently been plagued by a series of tritium releases.  The site has experienced eight leaks between 1996 and 2006, including one in 1998 and another in 2000. The 1998 leak resulted in the release of three million gallons of tritium-contaminated water. It was not until November 2005 that the leaks were revealed to state officials. The public was not informed until the following month. Tritium-contaminated water has since been found in at least one drinking well and beyond the site boundary in a forest preserve. Residents from the local area have filed a class action lawsuit against Exelon over potential health problems and loss in property values. On March 16, 2006, the state of Illinois filed a lawsuit against Exelon seeking $36.5 million in fines for both the company's failure to properly maintain the underground pipeline that leaked and their delay in notifying state officials.


In February 2006, a tritium leak was discovered at the Byron Nuclear Generating Station, another Exelon plant in Illinois. The tritium levels in vaults along pipes that transport waste water were at four times the EPA standard. It is not yet clear whether these elevated tritium levels have reached the groundwater.


The Dresden Generating Station in Grundy County, Illinois is a third Exelon nuclear plant that has had recent tritium leaks. A 2004 test following the October discovery of a pipeline leak revealed groundwater tritium levels at 500 times the federal limit. A second leak was discovered on February 12, 2006, and follow-up tests found tritium levels 25 times higher than the EPA safe drinking water level.

Palo Verde

On March 2, 2006, Arizona Public Service (APS) reported to the state of Arizona that it had found water with a concentration of tritium three and a half times the EPA standard, in a maze of underground pipes at the Palo Verde site. Palo Verde discharges tritium into the air, and APS has suggested that some of it may have fallen back to the ground as rain. It is unclear if tritium has moved beyond the boundary of the plant or seeped into the underground aquifers that supply water to the local area.

Indian Point

In August 2005, high tritium levels were detected when workers dug a new foundation for a crane at the Indian Point site, which is operated by Entergy. The level in one well was thirty times the EPA standard. The source of the leak has not yet been pinpointed, although a leak in a spent fuel pool near one of the reactors is suspected. Local groups are concerned about contaminated water moving toward the Hudson river. In February 2006, strontium-90 was also detected at the site, and there was increased evidence that both radionuclides have reached the Hudson river. 

For more information on tritium, please see the Institute for Energy and Environmental Research's (IEER) Statement on Tritium and recent Memorandum on Exelon's explanation of the tritium leaks and groundwater contamination at Braidwood Generating Station.