Radiation surveys - Fukushima

Background - 30 October, 2014
Monitoring in the Fukushima area by Greenpeace radiation experts has provided valuable information to residents, helping them understand the risks they continue to face from high levels of radioactive contamination.

Expert teams have taken hundreds of radiation measurements on many occasions in towns just outside the 20 km exclusion zone around the Fukushima disaster site and in Fukushima City and Koriyama, 60 km from the disaster. Greenpeace monitoring began shortly after the accident on 11 March 2011. The teams have also tested soil, vegetables, seafood, and sediment.

Compilation data of all radiation monitoring to date

We have found radiation at levels high enough to raise health concerns for the people who continue to live daily with this contamination. We have also shown that the authorities have consistently underestimated both the risks and extent of radioactive contamination. Based on our results we called for a significant extension to the evacuation area, which was later implemented. We advised that until decontamination was completed, children should be held back from their schools to avoid high radiation levels. We have also found that official monitoring stations systematically underestimate the radiation risks for the population.

Our analysis of the threats to public health have given residents an alternative to the often contradictory information released by Japan’s authorities since the Fukushima disaster began.

The teams are made up of Greenpeace radiation experts who have been trained in radiation monitoring and the use of sophisticated measuring devices. 

Locations and details of radiation levels to date are shown on the maps below. Click a flag for details on the levels of contamination found. Raw data as well as sample analyses can be found in spreadsheets further down the page.

Summary of field trips

October 2014: Iitate, Kawauchi village, and Tamura city

The new radiation monitoring results from Iitate (40km from Fukushima Daiichi nuclear power plant), Fukushima city (60km), Miyakoji of Tamura city (20km) and Kawauchi village (20km) showed that efforts at decontamination were still failing to reduce contamination in many areas to meet the Japanese government’s long-term decontamination target level of 0.23micro Sv/h. The decontamination efforts generate vast amounts of radioactive waste, being piled up at temporary sites throughout the prefecture.

October 2013: Tamura City (Miyakoji)

Greenpeace experts show that after the government's massive decontamination efforts in Tamura City, radiation levels on roads, in forests and in and around houses are still higher than the target of 0.23 microSievert per hour promised by the government: 39% of the 18,180 measured points on roads exceed the government target level. Tamura was the first community where the government lifted the evacuation order, leaving Tamura City residents with a terrible dilemma: move back even though radiation levels remain too high or abandon their assets without proper compensation.

October 2012: Fukushima City & Iitate

Greenpeace found that more than 75% of the 40 checked monitoring posts showed lower radiation levels than their immediate surroundings, with levels within 25 metres up to six times higher than at the posts themselves. Also the team found that the cleanup in a trial decontamination area in Iitate has so far been insufficient, with radiation levels up to 5 uSv/h (at 1m) recorded in a residential area.

March 2012: Fukushima City

One year after the Fukushima disaster, Greenpeace found that radioactive contamination is concentrating in many places, creating hotspots that create serious threats to people’s health. For example, the team found hot spots of 70μSv/hr (at 10cm) in a parking garage 50 metres from the central train station, and 40μSv/hr in a water drain next to housing, representing  up to 1,000 times normal background levels.

December 2011: Fukushima City

Greenpeace monitored the Watari and Onami neighbourhoods of Fukushima City and found hotspots of up to 37 μSv/hr (at 10cm) in a garden in Watari, and 10.1 μSv/hr in bags of dirt, seemingly abandoned, on a road in Onami.

April 2011: Fukushima prefecture

Less than 4 weeks after the disaster started, Greenpeace measured radiation levels and took samples at various places in Fukushima prefecture. The teams recorded radiation levels in Fukushima City and Koriyama, high enough to expose people to the maximum yearly dose of radiation allowable in a matter of weeks. The teams also found radiation levels above official limits in vegetables. Greenpeace called for full evacuation of several high radiation areas including Iitate and Namie that were later evacuated. We also called for the greater Fukushima area to be given official protective status and for children and pregnant women to be evacuated from high risk areas in Fukushima City and Koriyama.

Monitoring results - Data

We're posting raw data from our field teams here as we can.  Our team's priority is updating the map (above), and informing local communities, so there may be delays in publishing the raw data.  Our intention is to publish spreadsheets for all our monitoring work (though some may have to be published after the end of field work for logistical reasons). These will contain the same information as in the map.  By posting these spreadsheets, we hope to make it easier for people/institutions who want to use our data as part of their own research efforts.  (By combining it with government data for, example, or using it in ways we have not imagined.)

Use of this data

This data is released under an Open Data Commons Attribution license.  Please DO:  Re-publish, mash-up, re-mix, share and create new works from this data. Please DO: Cite us as the source and link to this page.  Please DO NOT: Imply that Greenpeace endorses your product or interpretation (we're only an original data source).


Team 1 - Gamma spectrometer output, 04 April 2011 (xls)

Team 2 - Field log, 04 April 2011 (xls)

Team 2 - Field log, 07 April 2011 (xls)

Food Testing results, 04-08 April 2011 (xls)

Marine testing preliminary results, 12 May 2011 (xls)

Marine testing lab results 1, 25 May 2011 (pdf)

Marine testing lab results 2, 25 May 2011 (pdf)

Marine testing lab results 3, 09 August 2011 (pdf), (more info)

Detailed Demands to the Japanese Government, August 2011 (pdf)

Letter to National Government, August 2011 (pdf)

Fukushima/Watari/Onami results, December 2011 (xls)

GP Radiation Monitoring Fukushima, October 2012 (xls)

GP Radiation Monitoring Iitate, October 2012 (xls)

GP Radiation Monitoring Data, October 2014 (pdf)