FACT: It is illegal in the United States to sell, offer for sale or promote via any means that touches interstate commerce (which would include any communications form that crosses a state line) any drug or device intended to treat, prevent or cure any disease or disorder of the human body without proof in the form of random clinical trials which are then submitted and analyzed by the FDA. This is controlled under the Food, Drug and Cosmetic Act (Title 21 USC.) The government goes after sellers of supplements and devices on this basis all the time. The law is crystal clear in this regard; both safety and efficacy must be scientifically proved, reviewed and then formally approved by the FDA. FACT: There are protocols for "compassionate use" and similar for drugs and devices in the pipeline for approval, or approved in other nations, but such are specific to an individual person and circumstance (e.g. in the event of a terminal illness) and cannot be ordered as either a "standard of care" nor ordered against someone's expressed desires.
FACT: Flu-like illness (ILI) kills roughly 60,000 Americans a year. As a result of that significant toll of death and disease we have studied the means by which such transmission can be modified or interrupted entirely for roughly the last 100 years dating all the way back to the Flu Pandemic of 1918, including but certainly not limited to random clinical trials, both in health care settings and in the general population.
FACT: There are multiple random clinical trials that have been performed on the efficacy of face coverings of various sorts, from N95 masks on down to cloth coverings in the general population with the aim of identifying effective means of controlling the spread of ILI ("influenza like illness"), specifically respiratory viruses.
FACT: There is NO record established by said Random Clinical Trials (RCTs) in over one hundred years, including those performed in the last 20 years, that establishes statistically-significant effectiveness of face coverings for the prevention of transmission of ILI. Exactly zero science supports such a claim.
FACT: As a direct result of the lack of such evidence the FDA has never issued an approval for any facial covering intended to be used in the general population for the suppression of any illness, including but not limited to Covid-19. In fact I suspect no such approval has ever been sought, otherwise someone would have tried to make money on a "flu mask", making such a medical claim, in previous years.
FACT: It is therefore UNLAWFUL under United States Law for any seller to advertise, market, sell, vend or represent that any facial covering in fact does or will prevent, treat or cure any transmissible disease whatsoever as exactly zero said devices when used by the general population have ever been certified and approved for said use. THIS IS FEDERAL LAW (TITLE 21) AND IS NOT A SUGGESTION.
This is why every package of N95 masks at the Home Deport (and elsewhere) has the clear statement on the "use document" that comes with it which states it does not prevent the transmission of any disease.
To not so-state would be a violation of federal law.
It is thus likewise impermissible for any element of a State or Local Government to mandate the use of a device that is not FDA approved for such a purpose since it is flatly against the law to recommend or so state that an unapproved drug or device is safe or effective to cure, treat or prevent any disease.
Such a government entity is in fact mandating a direct violation of United States Federal Law and committing said violation itself through promotion of said use.
END OF DISCUSSION.