Although progress on the reactor design at Metallurgical Laboratory and DuPont was not sufficiently advanced to accurately predict the scope of the project, a start was made in April 1943 on facilities for an estimated 25,000 workers, half of whom were expected to live on-site.
Malia que o progreso no deseño de reactores no Laboratorio Metalúrxico e por parte de DuPont non estaba o suficientemente avanzado como para predicir con exactitude o alcance do proxecto, os traballos nas instalacións comezaron en abril de 1943 cunha estimación de 25 000 traballadores, coa metade destes vivindo no lugar.