Because of the dirty nature of this blast, fallout will be an especially important effect to consider. This blast will likely deposit measurable, if not harmful, amounts of radioactive debris across much of the US, in the form of delayed fallout over the next several months. Even more important are the localized effects that the early fallout, defined as all the fallout occurring in the first 24 hours, will have on the survivors, rescue workers and those not directly affected by the blast but living in the vicinity of San Francisco
In a surface blast, fallout consists of neutron activated weapon debris, fission products, unused fission