This page mirrors data available through the Open Government, Open Data website that contains information and measurements made by Health Canada in response to the Fukushima Dai-ichi disaster which began March 11, 2011.

This dataset provides the results obtained by two radiation monitoring networks operated by Health Canada: the Canadian monitoring sites of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) and the Canadian Radiological Monitoring Network (CRMN). More information about the CTBT and its monitoring network is available here and http://www.ctbto.org/. Further information on the CRMN network is available here.

The results provided are activity concentration and uncertainty for various nuclides in the months following the Fukushima Daiichi nuclear accident. Reported are the naturally occurring radionuclides: beryllium-7 (⁷Be) and lead-210 (²¹⁰Pb), and all anthropogenic radionuclides observed: cesium-134 (¹³⁴Cs), cesium-136 (¹³⁶Cs), cesium-137 (¹³⁷Cs), iodine-131 (¹³¹I), iodine-132 (¹³²I), iodine-133 (¹³³I), tellurium-129 (¹²⁹Te), tellurium-129m (^129mTe), tellurium-132 (¹³²Te), technetium-99m (^99mTc), lanthanum-140 (¹⁴⁰La), and the radioactive gases: xenon-131m (^131mXe), xenon-133 (¹³³Xe), xenon-133m (^133mXe), and xenon-135 (¹³⁵Xe). The absence of data for a specific nuclide indicates that it was either below the detection threshold or absent. The data comes from the measurement and analysis of particulates accumulated in filter media or from xenon gas extracted from the atmosphere. Cascade summations corrections were applied to ensure reporting of the true physical relationships among the observed radionuclides.

Throughout the accident period, the measured activity concentrations of all radionuclides represent only a small fraction of the typical annual background exposure from natural sources of radiation. Therefore, these levels do not present any risks to the health of Canadians.