Warned that disclosing the project's secrets was punishable by 10 years in prison or a $10,000 ($108,000 today) fine, they saw enormous quantities of raw materials enter factories with nothing coming out, and monitored "dials and switches while behind thick concrete walls mysterious reactions took place" without knowing the purpose of their jobs.
Advaret om at afsløring af projektets hemmeligheder kunne straffes med 10 års fængsel eller $ 10.000 i bøde, kunne de se enorme mængder materialer ankomme til fabrikkerne, mens der ikke kom noget ud i den anden ende, og overvåge "visere og kontakter mens der bag tykke betonvægge foregik mystiske reaktioner" uden at kende formålet med deres job.