How dangerous is the radiation from the damaged Japanese nuclear reactors?
The effects almost certainly will not go far beyond the borders of Japan. For now, the chief radiation danger is to plant workers desperately trying to mitigate the disaster.
Some of the workers trying to prevent a meltdown have already suffered radiation sickness and injury from explosions related to hydrogen buildup outside the reactor core.
"The scariest outcome from such releases of radiation are the immediate effects, which are going to be only felt by personnel who have to go into the building and shut it down," radiation biologist Jacqueline P. Williams, PhD, tells WebMD. Williams is a researcher in the department of radiation oncology at the University of Rochester, N.Y.
After the Fukushima Daiichi plant disaster started, radiation levels in Tokyo were reported to be 20 times above normal but still not in the danger zone. A no-fly zone was imposed for an 18-mile radius around the nuclear plant.
Officials in Japan have warned that babies in and around Tokyo should not be given tap water, which has been found to contain levels of radioactive iodine at twice the upper limit recommended for babies, according to media reports.
Japan has also banned the sale of raw milk, spinach, and certain other vegetables from several areas of Japan.
On April 11, a month after the disaster, Japan raised the radiation alert status to its highest level, level 7 -- the same as the Chernobyl plant meltdown in Russia. It had previously been at level 5. What does this new status mean?
The reclassification doesn’t mean that the situation has gotten worse, says Henry Royal, MD, professor of radiology and associate director of the Mallinckrodt Institute of Radiology at Washington University in St. Louis. Rather, it’s acknowledging that the scope of the radiation leaked from the plant was larger than originally thought.