Thank you, that is indeed a source and I have raised my estimate of the probability larger casualties slightly. (For the record: above excerpt is from an article in the online magazine CounterPunch [1], which itself refers to the 2009 book [2].)

However, its methodology and rigour have been criticised [3]. As I am not an expert in this area I cannot evaluate the source directly, but several general heuristics apply. The source is a single book. (I am aware that the book claims to rely on numerous non-english sources, but I do not believe that they make the same claims.) The book relies on observational epidemiological data, which is generally hard to get right, and dose-response curves seem to be not analysed (seeing a relationship between doses and effect sizes is a good way to exclude spurious correlations). Finally, since the article mentions Yablokov's prior occupation I will also note that he founded and lead the Soviet chapter of Greenpeace, an organisation with a strong anti-nuclear position.

So I do not think that this is strong evidence. (But as I said earlier, I do currently consider it weak evidence.) In any case, the book claims one million deaths, not multiple millions, and only a fraction of those is attributed to thyroid cancer.

[1] https://www.counterpunch.org/2022/03/02/russian-takeover-of-...

[2] https://web.archive.org/web/20110419144513/http://www.strahl...

[3] https://en.wikipedia.org/wiki/Chernobyl:_Consequences_of_the...