RadNet Overview

RadNet is a national network of more than 200 monitoring stations distributed across all 50 states and the American Territories. These stations regularly sample the nation's air, precipitation, or drinking water for a variety of radionuclides (e.g., iodine-131) and radiation types (e.g., gross beta (β)). During its operation beginning in1973, RadNet's predecessor, the Environmental Radiation Ambient Monitoring System (ERAMS), collected over a half million high quality environmental samples. The current database primarily provides data that was collected between 1978 and present.. Some older "pre-ERAMS" data is included, and additional data will be added soon. Click here to view the RadNet Search User Guide, which provides more detail on the data.

RadNet normally samples radiation in all media on a regularly defined schedule. In the event of a threat of a significant radiation release RadNet typically will increase the frequency of sampling and generate many more data records for a given period of time compared to its routine operation. This was done in 1979 following the Three Mile Island nuclear reactor accident in the U.S., in 1986 following the Chernobyl nuclear reactor accident in the Soviet Union, in 1999 following the Tokaimura nuclear fuel processing facility accident in Japan, in 2000 following the Los Alamos and Hanford wildfires in the U.S., and in 2001 following the terrorist attacks in the U.S.

RadNet data provides a means to estimate levels of radioactivity in the environment, including background radiation as well as radioactive fallout from atomic weapons testing, nuclear accidents, and other intrusions of radioactive materials. RadNet also provides the historical data needed to estimate long-term trends in environmental radiation levels.

See the RadNet Timeline to help identify the occurrence of changes or events involving the monitoring system. Also, see Legal Basis for additional background.