The market for medical face masks is flooded by opportunistic traders and false certificates. Thirty to forty percent of research agencies that test medical face masks for hospitals in particular do not pass testing (read our guide on applicable legisalation). According to the article up to 80% (!) of the medical face masks on offer do not offer the promised protection. The result of that chaos: an abundance of medical masks that are not safe enough for use in health care.
The full article can be read via this link (turn on translation, the article is written in dutch).