ABC was first to report Friday the administration had paused the firings, after realizing the critical role these workers play in national security.

The NNSA maintains the U.S. nuclear stockpile, among other key nuclear and national security roles.

"The termination letters for some NNSA probationary employees are being rescinded, but we do not have a good way to get in touch with those personnel," an internal email obtained by ABC News says.

Most fired employees lost access to email. Many are now getting calls on personal phones.

Then, in a reversal, firings were PAUSED. Managers told ABC they frantically called many employees back to say they weren’t fired after all.

Now, I’m told Dept of Energy is going through who should be let go & who shouldn’t at a key national security agency 2/2

…and my colleagues, promising to work with Congress to ensure public access to information and to base vaccine recommendations on data-driven, evidence-based, and medically sound research. These commitments are important to me and, on balance, provide assurance for my vote.”

…Vaccines have saved millions of lives, and I sought assurance that, as HHS Secretary, he would do nothing to make it difficult for people to take vaccines or discourage vaccination efforts. He has made numerous commitments to me…