There are areas where natural radioactivity or chemicals just occur at dangerous levels. So it is certainly not a new problem to spot and avoid those areas. So

There are areas where natural radioactivity or chemicals just occur at dangerous levels. So it is certainly not a new problem to spot and avoid those areas. So in xx years: Either humans still have technology, and they can find out there is contamination with a Geiger counter or chemical analysis, and stay away as much as possible from the contaminated area. Either they lost technology/knowledge, and they will over time find out the place is unfit for life, through unborn babies, malformed animals/human, or other signs, just like the ancients did. In this case, our warning signs are of no help either, may actually be counter productive. I stand by the idea that's the kind of article that's not worth reading past the title.