It is my opinion the Virginia ETS, although well-intentioned, was borne of panic, and no other state I am aware of promulgated similar standards.  The recent increase in COVID-19 cases in Virginia is reportedly a result of social gatherings over the Thanksgiving holiday and less likely workplace exposures; indicative of behavior outside the workplace.   

I do not think it is the place of the DOL to address public health issues manifesting outside the workplace, much less citing employers for health issues brought into the workplace by employees who unknowingly are carriers of an infectious disease.  The Virginia Department Of Health and localities are better suited, better equipped and have the professional resources necessary to deliver solutions.

Lastly, it appearing that there is a "light at the end of the tunnel" with the introduction of vaccines that will hopefully end the pandemic.  Accordingly, I do not think implementing a permanent standard is appropriate or necessary.  Students of the VOSH Occupational Safety And Health Standards will find numerous respiratory and sanitation standards already in place.