Although he maintained that he did not divulge any nuclear secrets to his previous boss (Joliot-Curie), General Groves, the head of the Manhattan Project, had Halban removed from his job in Montreal, and replaced by John Cockcroft.
Ačkoli tvrdil, že svému bývalému šéfovi Joliotovi-Curiemu neprozradil žádné jaderné tajemství, generál Groves, vedoucí projektu Manhattan, odebral Halbanovi místo v Montrealu a nahradil ho Johnem Cockcroftem.