Technicalities
How bad radioactivity is depends on what kind of radioactivity and where it's delivered. U-238 is an alpha emitter, and quite harmless outside the body. The reason it's deadly in Iraq, where cancers and birth defects have increased many times, is that as ammunition it becomes an aerosol that lodges in the lungs and other organs.
Alpha particles are highly charged helium ions. A piece of paper or thick skin stops them fine. But inside the body, they are the deadliest radiation there is. This is why a speck of plutonium oxide in the lungs - very similar to uranium oxide except for its greater radioactivity - is a death sentence by lung cancer. Specks of depleted uranium are less bad than that, it's true, but the US has delivered lots of them, and with great effect. You don't see a lot of breast cancer in 10-year-old girls outside Iraq.
The Hiroshima bomb didn't leave a lot of uranium - it only amounted to about 140 pounds of it to start with, a miniscule fraction of what the US military has delivered to the civilian population of Iraq. The bomb's radioactivity was delivered by the flash and by the fission products from the 140 original pounds of uranium, many of which were gases or had short half-lives. It was all gone very soon, with a few exceptions like Strontium-90, which is bad because it lodges in bones. Sr-90 is a beta emitter, far less dangerous within the body than alpha emitters like U-238, and with a half-life of only 28 years , unlike U-238, which at 4.5 billion years is forever, once lodged in the body as small particles.
The US military acknowledges over a thousand tons of uranium munitions, roughly half of which remain as fine dust. That's why it will be killing, aborting, and causing hideous birth defects and cancers forever.
The US military is fully aware of all of this and has been at least since a memo written to General Lesley Groves in October 1943 concerning the use of fine radioactive dust against civilian populations. Uranium is not mentioned in the memo, because at the time it was very expensive and they didn't have much, but everything they say about the effects of long-lived beta emitters is all the more true of eternal alpha emitters buried in the lungs, and that was well known at the time. So what they proposed to do then with other radioactive isotopes they have done more effectively and permanently with the enormous amounts of waste uranium they now have.
The Groves memo is easily found if you google Groves memo October 1943. Here is one link:
http://www.mindfully.org/Nucs/Groves-Memo-Manhattan30oct43.htm
The absurd denial of completely uncontroversial facts about radioactivity, notably the effects of alpha radiation within the body and what may be expected when such tiny particles lodge in the lungs, is ludicrous. It resembles the similar denial by tobacco companies of the same effects on the lungs from cigarette smoke. The statistics on birth defects, child cancers, and the like around Basra after the first Gulf War are no more deniable than the gas chambers at Auschwitz, but that hasn't stopped the guilty in each case from denying either. Bloodguilt is a spiritual poison that works the same in all humans - Germans, Americans, Japanese, or any others- and it should not surprise us to find the same symptoms in all that are so affected.
The good news is the remedy stated so clearly long ago by John the apostle, "If we confess our sins, he is faithful and righteous to forgive us our sins, and to cleanse us from all unrighteousness." It's no accident that John pointedly does not specify that we need to confess them to God in particular, since we may not believe in him.
It's a good thing that that is no obstacle, because as John points out in the next verse, while we're denying our sin we're making God a liar and never believing in him -whatever may be our religious patter. So before we even think about God, let's confess the bloodguilt we have incurred through the murders we have approved or winked at, and then maybe we will believe in God. But whether we do or not, we will at least be free from that burden, and with a better chance that we can think straight about other things.
It's just the same way that a drunk needs first to sober up before he can make sense about God or anything else. Mass murder and alcoholism are much the same; it's just what we're drinking that's different. So the addicts act the same, and they need the same treatment.