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Japanese Nuclear Emergency: Radiation Monitoring

Data Summaries

EPA no longer updates the information at this link, but it may be useful as a reference or resource. This site contains information and data from March 11, 2011 to June 30, 2011. EPA has returned to routine RadNet operations. This site will continue to be available for historical and informative purposes.

For real-time air monitoring data, please visit the EPA RadNet website and Central Data Exchange. To view both current and historical laboratory data, please visit our Envirofacts database.

After a thorough data review showing declining radiation levels related to the Japanese nuclear incident, EPA has returned to the routine RadNet sampling and analysis process for precipitation, drinking water and milk.

As always, EPA's RadNet system of more than 100 stationary monitors will continue to provide EPA scientists near-real-time data on the slightest fluctuations in background radiation levels. Due to the consistently decreasing radiation levels, EPA is evaluating the need to continue operating the additional air monitors deployed in response to the Japan nuclear incident. EPA will continue to analyze air filters and cartridges from all air monitors as they arrive at the laboratory and will post the data as available.

In accordance with normal RadNet protocol, EPA will be analyzing milk and drinking water samples on a quarterly basis and precipitation samples as part of a monthly composite. The next round of milk and drinking water sampling will take place in approximately three months.

It is important to note that all of the radiation levels detected by RadNet monitors and sampling have been very low, are well below any level of public health concern, and continue to decrease over time. EPA continues to work with federal partners to monitor the situation in Japan and stands prepared to accelerate radiation sampling and analysis if the need arises. Data will continue to be available on EPA's public website.

June 16, 2011

Today, EPA released the final results from the second round drinking water samples, which were previously analyzed for iodine. 40 samples were analyzed. No radionuclides of concern were detected. To view the most recent drinking water data, go to https://www.epa.gov/japan2011/rert/radnet-sampling-data.html.

June 1, 2011

Today, EPA released new drinking water data. One sample detected very low levels of cesium-137. The level detected is far below a level of public health concern. To view the most recent drinking water data, go to https://www.epa.gov/japan2011/rert/radnet-sampling-data.html.

May 24, 2011

Today, EPA released new data for drinking water, precipitation and milk. Results from two precipitation samples detected low levels of radioactive material consistent with estimated releases from the damaged nuclear reactors. These detections were expected and the levels detected are far below levels of public health concern.

To view the most recent sampling data, go to https://www.epa.gov/japan2011/rert/radnet-sampling-data.html.

May 3, 2011

Today, EPA released new data for drinking water, precipitation and milk. Results from one drinking water and two precipitation samples detected low levels of radioactive material consistent with estimated releases from the damaged nuclear reactors. These detections were expected and the levels detected are far below levels of public health concern.

To view the most recent sampling data, go to https://www.epa.gov/japan2011/rert/radnet-sampling-data.html.

View previous data summaries

Due to the consistent decrease in radiation levels across the country associated with the Japanese nuclear incident, EPA will update this data summary page only when new data are posted. Historical data summaries will continue to be accessible from this webpage.

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