I happen to be reading Behind the Fog and Oppenheimer approved all sorts of human experimentation programs under "radiological weapons" programs: rather than a bomb, using radioactive materials to poison people. To figure out how to do that, US scientists injected plutonium and other radioactive substances into civilians without their consent, to study how fast the poisons would be excreted and what they would do to the subjects. Sometimes it was expected that this would kill the victims. They also did some direct tests with neutron beams on (usually) terminally-ill patients.

Although the military said that the program was interested in area denial ("nobody can use this factory or they'll get sick") a lot of these applications are obviously civilian-only.

Does Nolan include anything on that? Or is it just him totally not realizing this bomb was gonna be used on the working class, I swear bro?

edit: to be clear the US did far more extensive radiological tests on US civilians through the 60s, Oppenheimer just wasn't around for the later stuff. Behind the Fog is primarily about when they dumped lots of radioactive dust into poor parts of St. Louis to see what would happen to the people there. Fun for the whole family!