Had Pierre Curie not died in an accident, he would most likely have eventually died of the effects of radiation, as did his wife, their daughter Irène, and her husband Frédéric Joliot.
What actually happened is Joliot turned into a supervilain, he killed Pierre Curie before he could become a superhero, but was ultimately defeated by Henri Bequerel, who is immortal.
I thought this was common knowledge.
In the meantime Irene Joliot died of the radiations, as everybody would expect.
Most likely she melted into a sentient beam of radiation and is blasting all around the world, interfering with various radio signals, and science experiments, like John Bell's - just to fuck with Einstein.