To be sure, 'not for medical use' probably means that the manufacturer of the mask didn't want to pay (in money and/or effort) to go through the regulatory proc

To be sure, 'not for medical use' probably means that the manufacturer of the mask didn't want to pay (in money and/or effort) to go through the regulatory process to obtain an official rating; this has more to do with what the market wants (cheap masks! who cares about ratings!) than the government.