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Japanese Nuclear Emergency: EPA's Radiation Monitoring

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Fukushima Information and Resources

EPA’s air monitoring data have not shown any radioactive elements associated with the damaged Japanese reactors since late 2011, and even then, the levels found were very low—always well below any level of public health concern.

We are providing the following links to the most current information from trusted scientific organizations that continue to monitor the situation:

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.

June 30 Statement

In response to the Japanese nuclear incident, EPA accelerated and increased sampling frequency and analysis to confirm that there were no harmful levels of radiation reaching the U.S. from Japan and to inform the public about any level of radiation detected. After a thorough data review showing declining radiation levels, on May 3, 2011, EPA returned to the routine RadNet sampling and analysis process for precipitation, drinking water and milk. As always, our 24/7 air monitoring stations continue to measure radiation levels, alerting scientists to even slight changes.

It is important to note that all of the radiation levels detected by RadNet monitors and sampling have been very low, well below any level of public health concern. Across the RadNet system, we saw decreasing radiation levels during April and May. Since May, sample analyses have predominantly shown no detections of radionuclides associated with the Japanese nuclear incident. 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.

EPA's nationwide radiation monitoring system, RadNet, detects radiation in two ways: air monitoring and sample analysis.

Air Monitoring: More than 100 air monitors measure radiation 24 hours a day, 7 days a week. This system allows our scientists to keep very close watch over radiation levels at all times. This system lets us identify normal background radiation levels in an area. The air monitoring system alerts us if radiation levels increase outside of this normal range, allowing us to take action if necessary. Get the data | Learn more about 24/7 monitoring

Sample Analysis: During normal operations, EPA analyzes precipitation samples every month, and drinking water and milk samples every three months. This analysis allows us to detect minuscule amounts of radioactive material and gives our scientists information about the specific radioactive materials present. Get the data | Learn more about lab data


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