Our atmosphere has low enough pressure and levels of deuterium that nuclear fission in air doesn’t cause hydrogen atoms to fuse into helium. If things were a bit different, a nuclear explosion might have caught our atmosphere on fire.
So what was the debate like? Who wad debating the issue? Were there a lot of concerned scientists?
It wasn't much of a debate. The possibility of chain reactions in the atmosphere was considered (nitrogen fusion, nitrogen + nitrogen -> oxygen + carbon + energy, rather than deuterium fusion). This possibility had been suggested by Teller in 1942, and the general scientific opinion was that this was impossible. However, the consequences of such a reaction could be quite serious, so it was checked in more detail. Conclusion after further research: impossible. Arthur Compton had a dissenting opinion: not impossible, but highly unlikely; he estimate the probability of such a fusion reaction at about 1 in a million.
For a more detailed past answer, see:
and also, on the calculations of the possibility of such reactions, by u/restricteddata