There was a release to atmosphere of radioactive material that spread across the UK and Europe . The fire released an estimated 740 terabecquerels ( 20,000 curies ) of iodine-131 , as well as 22 TBq ( 594 curies ) of caesium-137 and 12,000 TBq ( 324,000 curies ) of xenon-133 , among other radionuclides . Later reworking of contamination data has shown national and international contamination may have been higher than previously estimated . For comparison , the 1986 Chernobyl explosion released approximately 1,760,000 TBq of iodine-131 ; 79,500 TBq caesium-137 ; 6,500,000 TBq xenon-133 ; 80,000 TBq strontium-90 ; and 6100 TBq plutonium , along with about a dozen other radionuclides in large amounts . The Three Mile Island accident in 1979 released 25 times more xenon-135 than Windscale , but much less iodine , caesium and strontium . Estimates by the Norwegian Institute of Air Research indicate that atmospheric releases of xenon-133 by the Fukushima Daiichi nuclear disaster were broadly similar to those released at Chernobyl , and thus well above the Windscale fire releases
Three Mile Island accident
Three Mile Island accident
Windscale fire