Once the radiation level becomes too high, we turn back.

We learned later how high the radiation levels were there at the time.

This was probably the cause of the high radiation levels measured.

The radiation levels 70 years ago would have been lethal.

The radiation levels here were high enough to kill him with a few hours' exposure.

It all depends upon the radiation levels, but I wouldn't think we'd land.

But I want to see what the place looks like and we need to get some better data on radiation levels.

This system allows our scientists to keep very close watch over radiation levels at all times.

Yes, radiation levels will be lower on the surface than in the mines.

"Radiation levels fall off very rapidly, and that seems to provide a good level of protection."