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.
Toke Atoll
Toke Atoll was within the fallout zone of the Castle Bravo nuclear test. The degree of contamination in coconuts and coconut crabs is unknown, but levels are monitored on nearby Utirik.