Who knew about radiation sickness, and when?

Marie Curie died of acute aplastic anemia [1], at age 66, after decades of working with radioactive materials and operating an unshielded X-ray machine thousands of times during World War I.

While long term radium exposure has been known to be hazardous by the 1930s, and Curie's work had been suspected at the time to have affected her health, I estimate that contemporary thinking would have been to avoid exposure to radium.

Conversely, I do not think that acute exposure to radiation happened enough before World War II to have any kind of safety thinking around it.

[1] https://en.m.wikipedia.org/wiki/Marie_Curie