A-blast A-bomb shelter H-blast Mach front activity air pollution airborne radioactivity artificial radioactivity atom blast attritus blast wave bran contamination cosmic dust crumb crumble curiage decontamination dust dust ball dust cloud efflorescence fallout shelter farina filings fission particles flash burn flour grits groats ground zero half-life hydrogen blast kittens lint meal mushroom cloud natural radioactivity nuclear radiation powder pussies radiant energy radiation radioactive dust radioactive radiation radioactivity radiocarbon dating radiolucency radiopacity radiosensibility radiosensitivity raspings saturation point sawdust smut soot specific activity