EUA was the type of authorization granted to Covid mRNA vaccines, along with hundreds of other medical products used during the declared Covid pandemic.

Once we understand the basic legal framework, we can investigate the most important aspect of EUA that nobody ever discusses: the context in which EUA law operates.

Legal Requirements for Emergency Use Authorization (EUA)
In order to issue EUA for a product intended for use in a civilian population, several steps have to happen, involving multiple government agencies. You'll find all the details here. The key step is the first one:

The Secretary of Health and Human Services (HHS) has to declare that there is an emergency specifically warranting EUA. And that situation always has to involve CBRN (chemical, biological, radiological, nuclear) agents, also known as WMD (weapons of mass destruction).

The specific EUA law applied to the Covid countermeasures is Section 564(b)(1)C of the Federal Food, Drug and Cosmetic Act. The law states that emergency use authorization for products intended for civilian use requires:

A determination by the Secretary of HHS that there is a public health emergency, or a significant potential for a public health emergency, that affects, or has a significant potential to affect, national security or the health and security of United States citizens living abroad, and that involves a CBRN agent or agents, or a disease or condition that may be attributable to such agent(s)