@g @LukeAlmighty
And there's no problem living in Hiroshima and Nagasaki, the only war targets where nukes were used.
As you said, depends a lot on the bomb quality. And doing nuclear tests is a vastly different matter than using the finished product.
I'm not familiar with the Marshall Islands themselves, but a lot of the early nuclear testing was much dirtier than what US manage to produce later on, because scientists really didn't know much about what would/could happen. Remember, there were some who genuinely believed there was a slim possibility for the entire atmosphere to ignite in a nuclear cascade reaction.

If it comes down to it, we'll have to see how many bombs each side has the guts to drop before they give up the war, but I don't really foresee a long term nuclear contamination issue, as much as I expect to see a problem of ruined infrastructure that will bring both countries to collapse. And we might see the rest of the world stigmatizing India and Pakistan for starting a nuclear conflict, so there's gonna be a reluctance to invest in the redevelopment of the two countries.