Lithium hydride
Before the Castle Bravo nuclear weapons test in 1954, it was thought that only the less common isotope lithium-6 would breed tritium when struck with fast neutrons. The Castle Bravo test showed (accidentally) that the more plentiful lithium-7 also does so under extreme conditions, albeit by an endothermic reaction.
Rongelap Atoll
Irradiated debris fell up to deep over the island. A United States military medical team visited the island with geiger counters the day after the fallout, but left without telling the islanders of the danger they had been exposed to. Virtually all the inhabitants experienced severe radiation sickness, including itchiness, sore skin, vomiting, diarrhea, and fatigue. Their symptoms also included burning eyes and swelling of the neck, arms, and legs. The inhabitants were forced to abandon the islands, leaving all their belongings, three days after the test. They were relocated to Kwajalein for medical treatment. Six days after the Castle Bravo test, the U.S government set up a secret project to study the medical effects of the weapon on the residents of the Marshall Islands.