Frequently asked questions about tritium

Answers to frequently asked questions about tritium at Fermilab.

If you have any questions about tritium at Fermilab, please call the Communication Division at 630-840-3351, or submit a question online.

Q: What is tritium?

A: Tritium is a form of hydrogen. It's a weakly radioactive isotope with a half-life of 12.3 years. When tritium decays into ordinary helium, it emits low-energy particles called beta particles. Although tritium can be found as a gas, its most common form is water. The Earth's atmosphere contains low levels of tritium produced naturally when cosmic rays strike air particles. At Fermilab, small amounts of tritium are produced as a byproduct of accelerator operations.

Q: Does the tritium at Fermilab constitute a health risk to employees or neighbors?

A: No. All tritium levels found on site are well below any federal health and environmental standards. High doses of tritium over a sustained period have been shown to increase the risk of cancer. However, tritium is only harmful if it's ingested over long periods of time in amounts far larger than those detected in Fermilab's surface and sanitary sewer water. Even if people were to drink the surface water or come in contact with sewer water on the Fermilab site, the body excretes tritium in about two weeks.

To keep people safe, federal agencies set limits on the amount of tritium in water. The U.S. Department of Energy limit for surface water is 2,600 picocuries per milliliter, and its requirement for sanitary sewer water discharge is less than a total of five curies in a year. The federal drinking water standard is 20 picocuries per milliliter. Fermilab's measurement of tritium concentration in the surface water and sanitary sewer water leaving our site typically is in single digits and the total tritium leaving our site in sanitary sewer is less than one curie.

Q: Is there tritium in the water that leaves the Fermilab site?

A: Yes. We have detected low levels of tritium in water flowing into creeks leaving the Fermilab site and in the sanitary sewer water that goes to the Batavia Wastewater Treatment Facility. All tritium levels found on site are well below any federal health and environmental standards.

The U.S. Department of Energy standard for surface water is 2,600 picocuries per milliliter. To date, the levels of tritium Fermilab has detected in Indian Creek at the site boundary have not risen above single digits. Fermilab rarely detects levels above single digits in the sanitary sewer discharge and the annual load (based on the discharge volumes and the concentrations) is well below the DOE requirement for sanitary sewer of less than five curies (or five million million picocuries) of tritium total per year. Fermilab is committed to keeping tritium levels well below the required limits. Fermilab's Tritium Task Force, comprising physicists and engineers from all corners of the lab, has taken many steps to minimize the amount of tritium in surface water on site. This group is focused on further reducing the levels of tritium in the sewer water discharge.

We routinely take samples of water from Indian Creek, Kress Creek and Ferry Creek at our site boundaries, and we post those results regularly. We also sample water from the sanitary sewers routinely, and those results are here.

Q: Where does the tritium leaving the Fermilab site come from?

A: Tritium is created as an expected byproduct of our accelerator operations, particularly the portion of our particle accelerator complex that creates and studies particles called neutrinos. Water with low levels of tritium is pumped out of the accelerator tunnels and used in our on-site industrial cooling water systems and cooling ponds.

Q: What steps have you taken to reduce the amount of tritium?

A: We took a series of steps to reduce the possibility of tritium getting into the three creeks and the sanitary sewers. We are committed to keeping levels of tritium as low as possible, both now and in the future.

Q: Does tritium get into the Fox River?

A: Yes, in very small, undetectable amounts. Water with low but detectable levels of tritium enters Indian Creek on the Fermilab site. After it leaves the Fermilab site, the creek continues another roughly five miles, gathering more water, before flowing into the Fox River. During this process the water containing tritium from Fermilab is diluted enough that the tritium is no longer detectable.

Fermilab also sends an average of 61,015 gallons of sanitary sewer water per day to the Batavia Wastewater Treatment Facility, which discharges its treated water into the Fox River. There is no treatment process that can remove tritium from water, but the low levels of tritium we measure in our sanitary sewer water is diluted to undetectable levels by the time it reaches the Fox River. The highest concentration of tritium measured in the sanitary sewer water as it leaves the Fermilab site was about 33 pCi/ml (in 2019), but is rarely detected at levels above single digits. By the time the water reaches the Fox River, that tritium has been diluted to an estimated level of 0.002 pCi/ml. For comparison, rain water contains tritium at a level of 0.1 to 0.3 pCi/ml. See Sewer Water Dilution graphic for more information.

Q: Is tritium affecting the ground water or well water?

A: No. Fermilab maintains a monitoring well network in the uppermost bedrock aquifer in which tritium has never been detected. On our site the aquifer is overlain by 50 to 80 feet of clay-rich glacial deposits. Numerous laboratory analyses of those deposits indicate surface water would take hundreds of years before reaching the aquifer. Tritium has a half-life of 12.3 years.

Q: Is fishing still allowed on site?

A: Not at this time. However, tritium only poses a health risk if it is ingested in large quantities over a long period of time. The levels of tritium we have detected in the ponds on the Fermilab site pose no danger to human health or to the environment. Tritium in the ponds does not harm the fish, since it does not accumulate in the body. Cooking that fish would drive much of the already low levels of tritium out.

Q: Does Fermilab expect tritium production to rise?

A: Yes. The laboratory is entering a new era of experiments with high-intensity particle beams, and generally speaking, the more intense the beam, the more tritium is created. As more of these experiments are constructed and come online, more tritium production is expected, and the laboratory will continue efforts to keep levels as low as possible.

Fermilab's Tritium Task Force is dedicated to that purpose, and tritium management and mitigation is being worked into the design of the lab's new experiments. As more of these experiments are constructed and come online, more tritium production is expected, and the laboratory will continue efforts to keep levels well below the standards we are required to meet.

Q: Where can I get more information about tritium at Fermilab?

A: This section of the website contains information on the different ways tritium leaves the Fermilab site: in surface water, in sanitary sewer water, as water vapor in the air, and as solid waste. If you have any concerns or questions about tritium at Fermilab, please call the Office of Communication at 630-840-3351 or submit a question online. We welcome your questions and will be pleased to provide additional information.