Here are some commonly asked questions about the earthquake and nuclear disaster in Japan.



Question: What are the health risks of radiation?
Answer: Radiation can kill at high levels: For example, 50 percent of people given whole body exposures of 400 rem would be expected to die within 60 days without medical attention, mostly from infections.
Acute Radiation Sickness often appears with exposure to between 50 and 100 rem. Symptoms include fatigue, hair loss, nausea, vomiting and diarrhea as well as skin changes such as swelling, redness, itching and radiation burns.
Exposures of less than 50 rem typically produce changes in blood chemistry, but no symptoms, according to the U.S. Environmental Protection Agency.
Experts say exposure to lower levels of radioactive materials has the potential to cause various kinds of cancers, with higher levels of radiation seen as more dangerous.


The highest radiation reading recorded so far at the Fukushima plant was 400 milliseiverts, or 40 rem, on March 14, according to Japanese authorities.

Question: What is the risk to the U.S.?
Answer: Most experts say they are not concerned because the level of radiation leaking from the damaged Fukushima plant is low and would be further dissipated by the jet stream before it hits the West Coast.


Question: Why are people snapping up potassium iodide tablets and Geiger counters?
Answer: May people are frightened and are acting out of an overabundance of concern. Potassium iodide is used to "block" the thyroid's intake of iodine-131, a radioactive isotope released during nuclear fission that can cause thyroid cancer. And Geiger counters are useful to help identify a radioactive object, but would not help detect background levels of radiation. Experts and public health authorities are not recommending that Americans take any precautions at this juncture. Click here for more from NBC Health Correspondent Dr. Nancy Snyderman on the health concerns.
Question: How will we know how much radiation is reaching the U.S.?
Answer: The U.S. cannot monitor sparse concentrations of radiation from space. However, the Departments of Defense and Energy and the Environmental Protection Agency and the Pentagon all have capabilities of monitoring radiation in the air. The Pentagon, for example, used its Constant Phoenix WC-135W aircraft, based at Offutt Air Force Base in Nebraska, to track radioactive radiation from the Soviet Union’s Chernobyl nuclear plant disaster in 1986.



Question: Will some products be difficult to find as a result of the disruption to the Japanese economy?
Answer: Experts say the auto industry will quickly be affected by the shutdown of manufacturing centers in Japan and the loss of thousands of automobiles in the tsunami. Prices and availability of electronic goods also may be affected, with Toshiba, Sony, Panasonic, Fujitsu and Mitsubishi all reporting disruptions to their production lines.

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