The danger from nuclear waste comes mainly from dust-like particles containing radioactive isotopes of iodine, cesium and strontium that could be released if the reactor fuel is allowed to become too hot.

FORBES: Fear Of Japan's Radiation Is Overdone

Radioactive isotopes accumulate in milk after they spread through the atmosphere, fall to earth in rain or dust, and settle on vegetation, where they are ingested by grazing cattle.

FORBES: Radiation Detected In Drinking Water In 13 More US Cities, Cesium-137 In Vermont Milk