The stuff you want to get rid of is radioactive dust and dirt.
Most of the city's population would have had less than half an hour to get under cover before radioactive dust fell.
They were just so much radioactive dust, the whole bunch of them.
The humans are slowly dying because of the radioactive dust caused by a human war.
It's pouring out radioactive dust and gases into the air.
Some areas of the city have been polluted by radioactive dust.
If the danger from radioactive dust doesn't stop, perhaps we'll all die.
"We'll all be radioactive dust if you let them shoot first, Jim."
I know that you had large supplies of radioactive dusts.
When they picked them up again at the building site, all radioactive dust had been safely rinsed away.