Well the final stages of
The Manhattan Project were all carried out in one location with all of the main players in one place.
If their work had caused an accidental catastrophic explosion, there wouldn't have been anybody left to continue.
Nor would any of their final research survived.
It would have been back to almost the basics for the US at that point with a lot of hand wringing about why and how.
Also remember, the Regula Project was developed By Carol & David knowing that "The Military" could subvert their work.
It seemed to me that they were quite adamant about keeping the major portions of it a secret from everybody.