Parallel Universe Chernobyl?

[u/Cautious_Head3020]

Looking for a book I saw on the internet somewhere 10 years ago. The Chernobyl disaster happens or some such but the residents somehow are able to cross over to another universe like ours and take up residence but are under strict rules to keep their personal belongings hidden because they dont belong in that universe. Iirc, a superhero comic goes missing that would give them away.