(FUKUSHIMA, Japan) -- Japan's nuclear agency raised the severity level of a highly radioactive water leak to a level three "serious incident" Wednesday. Contaminated water escaped from a storage tank at Fukushima Daiichi Nuclear Power Plant and was discovered Monday. At least 80,000 gallons have been released onto the concrete foundation and nearby soil.
Officials previously declared the incident a level one, the second lowest level on the International Nuclear and Radiological Event Scale. The heightened warning is the most serious issued since the 2011 earthquake and tsunami that caused three reactor meltdowns.
Workers placed a sand bag barrier around the leak, but it has proved ineffective in containing the water. The storage tanks hold fluid used to cool the core.
One puddle emitted 100 millisieverts of radiation an hour, which is equal to a five-year dose of radiation, said a Tokyo Electric Power Company general manager.
Levels of radioactive cesium and strontium higher than the legal safety limit are present in the leaked water, and exposure is known to increase the risk of cancer.
There is also another leak at the plant, a contaminated groundwater leak into the Pacific Ocean, reported in late July. Tepco has made efforts to inject chemicals into the soil to create a chemical wall in order to stop the leakage.
The level-three incident is the fifth leak involving similar tanks at the plant in the past year.
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