The only face mask regulated by OSHA was the N95 respirator. It was 3M that first developed the N95 for the coal industry. OSHA recommended them as a last resort in hazardous environments with high levels particulates. They were to be used for short temporary access to those environments. OSHA recognized that even after short periods of time, the N95 became useless due to moisture content build-up from the user's exhale, which acted to quickly hinder the mask's filtering capability. OSHA recognized that inhaled air increasingly was drawn from the perimeter of the N95. This is why OSHA recommended the N95 to be used as a last resort, for temporary use, and not for more than 20 minutes. The N95 respirator was never designed for prevention of air-borne germs, but for large dust particulates, such as found in the coal industry. When the 'COVID' lock-down occurred, OSHA conveniently hid all of their 50+ years of research and respirator guidelines to allow the N95 to be used for the first time for putative airborne germs, to which there has never been any foundational studies to back the use of the N95 respirator for preventing the spread of airborne germs.