Japan has evacuated civilians from areas surrounding the troubled plant, but Cirincione says radiation could spread far beyond Japan if efforts to contain the crisis fail.

Who is issuing this advisory following reports of people in Japan and elsewhere who are using the substance in response to radiation leaks from nuclear plants in northeastern Japan.

While the affected areas in Japan brace for more aftershocks, the country is also being afflicted by another earthquake-engendered crisis ― nuclear radiation.