[WalterBright]

After the Fukushima disaster, radioactivity was detected in the seawater off the west cost of America. This, of course, threw people into a panic, despite being detectable only with very sensitive equipment and was not a danger to anyone or anything.

[legitster]

To be more specific, you would not have been able to detect Fukushima waste based on radioactivity, as the radioactivity would not have been detectable above the normal background radiation.

They could only identify the waste by it's distinct radiological profile. Otherwise it was just another source amongst millions of ionizing radiation that bathes us every day.

[WalterBright]

> They could only identify the waste by it's distinct radiological profile.

Which is what happened.