Japan’s nuclear emergency
Damage at a nuclear power plant has made leaking radiation the primary threat facing a country grappling with devastation from a 9.0-magnitude earthquake and tsunami.
For a narrated animation of what happened, click here.
How dangerous is the radiation?
The highest reported level of radiation released from the Daiichi plant was 1,000 millisieverts per hour on March 27. The spreading contamination represents a critical safety concern for workers at the plant. On March 24, three workers were hospitalized for radiation burns to their legs and feet.
Effects of radiation
A blast of radiation often causes immediate, obvious symptoms, but damage from low levels of exposure -- generally 100 mSv or less -- may not appear for decades, if ever. Japanese officials have set a dose limit of 250 mSv for nuclear workers during emergencies.
- HIGH EXPOSURE
- LOW EXPOSURE
GRAPHIC: Wilson Andrews, Alberto Cuadra, Bonnie Berkowitz, Patterson Clark, Laris Karklis, Nathaniel Vaughn Kelso, Todd Lindeman, Alicia Parlapiano, Jason Samenow, Laura Stanton, Gene Thorp, Bill Webster, Karen Yourish - The Washington Post. Updated March 25, 2011.
Japan is one of the most active seismic areas in the world. More than a thousand earthquakes of 4.0 magnitude or greater have struck in and around the country since 2009.
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SOURCES FOR "JAPAN'S NUCLEAR EMERGENCY": Tokyo Electric Power Company; Mitch Singer, Biff Bradley, Rod McCullum and Alex Marion, Nuclear Energy Institute; IAEA; The National Academies Press; "Power Plant Engineering;" "Nuclear Reactor Engineering: Reactor Systems Engineering;" Bulletin of the Atomic Scientists; Japan Ministry of Land, Infrastructure and Transport; Nuclear and Industrial Safety Agency of Japan; Nuclear Regulatory Commission; U.S. Food and Drug Administration; Kenneth D. Bergeron, Training Centre for Nuclear Technology; International Nuclear Safety Center; Argonne National Laboratory; U.S. Dept of Energy; Global Seismic Hazard Assessment Program; United Nations Population Division; World Health Organization, World Nuclear Association; NOAA Hysplit Model; U.S. Nuclear Regulatory Commission; Environmental Protection Agency; Japan Nuclear Energy Safety Organization; CDC; Health Physics Society; Physicians for Social Responsibility; Thomas McKone, senior staff scientist at the Lawrence Berkeley National Laboratory; General Electric.