Heavy metal poison also develops over decades and enter the body primarily from the food we eat. Lead ruptures the red blood cells, causes axons of nerve cells to degenerate, and kills the immune system. It is a slow and painful death.
As a statistical thing, every item of steel that we own or use, like electricity and the devices that run on it, has statistically produced some amount of lead waste. It causes a half million death per year, it causes almost 10% of intellectual disability of otherwise unknown cause, and every single person who lives has some amount in them. You and me have lead in our bodies.
We can look at the waste from a nuclear plant, collected and stored and estimate how dangerous or how long it will last. We can also look at the waste from a mine, generally put in a large hole next to it, and estimate how dangerous it is and how long it will last. Mines generally also release a lot of waste into the environment like radon, so we can estimate how much radiation a mine is legally allowed to release into the environment compared to a nuclear plant.
If you live anywhere near a mine or where mining activity has occurred in the past, the level of radiation in the air from mining pollution is measurable and quite dangerous in high levels. Here in Sweden it's also recommended that people buy and own detectors in case those levels are too high, and fans with filters to remove the radon particles down to acceptable levels. There is no such recommendation for people who live near nuclear plants, despite Sweden having several of those. A bit odd is it not?
This is the reason why the numbers for the Chernobyl accident range from 30 direct vitims to 985,000 premature deaths.[1] The estimates (for nuclear ar well as for non-nuclear) also vary widely depending on the underlying models, where a lot of uncertainties about causes and effects are located. Just one example: Cancer develops over decades, because a cell needs to accumulate a certain amount of mutations to turn into a cancer cell. Exposure to radioactivity causes mutations. How does that influences premature deaths? Well, the more reputable studies estimate an average value of lost lifetime. As a statistical average it applies to everyone. Taken individually, this means that everyone has a premature death due to nuclear (as well as to any other risk whatsoever).
[1] See https://en.wikipedia.org/wiki/Deaths_due_to_the_Chernobyl_di...