the article mentions hexafluoride. but LANL did (and probably still does) hydrazine. source:

https://patents.google.com/patent/US2690378

(used to intern, and subsequently work there, although not as a chemist, of course. i'm not that smart)

and if you want to pedant that the patent wasn't issued to los alamos nat'l laboratory... well, in '54 things were different :)