What to Make of the CDC’s Mask Endorsement?

RationalGround.com offers Critical Analyses of the CDC’s Mask Endorsement.

In my 10/15/20 post – COVID Mask OSHA Requirements – I discussed the OSHA’s requirement for employers to choose equipment that is suitable to the hazards facing their employees, and for implementing a respiratory protection program.

Last week’s sweeping endorsement of face masks has prompted me to provide additional information for employers to take into account if they are considering masks for their employees.

 Ratonalground.com is a website that provides a wide array of resources about COVID-19. Please check out the recent posts by Megan Mansell and Karl Dierenbach, analyzing the CDC Statement. I provide links, below, and I include some of the text from each post.

1. CDC’s sloppy “Scientific Brief” adds nothing to the evidence for masks, by Megan Mansell.

“Let’s look at this oh-so-sloppy CDC Scientific Brief: “Community Use of Cloth Masks to Control the Spread of SARS-CoV-2,” which recommends “community use of masks, specifically non-valved multi-layer cloth masks, to prevent transmission of SARS-CoV-2.”

Really? OSHA doesn’t recommend cloth masks, as cloth masks have no production control variables to measure or assert percentage efficacy.  I suppose you could say they provide, at a minimum, 0% efficacy, and that would be an appropriate percentage, but you cannot assert percentage efficacy when you have unknown variables. This is why governing agencies like OSHA are critical–they prevent workplaces from knowingly exposing their workers to harmful substances and diseases, with corresponding grades of personal protective equipment (PPE) for each contagion type and applicable particulate behavior.” (My emphasis).

Megan Mansell is a former district education director over special populations integration, serving students who are profoundly disabled, immunocompromised, undocumented, autistic, and behaviorally challenged; she also has a background in hazardous environs PPE applications.

2. The Human Studies Cited by the CDC’s Recent Scientific Brief do not Support Community Masking, by Karl Dierenbach.

Picking up after the fifth paragraph:

“Anyhow, if the CDC is going to use such temporal evidence to support the idea of mask effectiveness, they have an ethical duty to also consider the opposite, where mask mandates do not have a temporal relationship to a decline in cases. Ian Miller has posted dozens of such charts at RationalGround.com here and here. Cherry-picking one study that happens to have mask-wearing coincide with a case decrease is disingenuous. Also, it is now clear the masks weren’t the driver in Arizona’s case reduction in July since they are still wearing masks and cases have begun to rise again.

Many of the studies cited by the CDC in the brief suffer from the same problem: they were conducted at a particular point in time, and subsequent events don’t support the idea that mask-wearing significantly limits the spread of COVID. One such cited study listed a host of countries that were wearing masks within 31 days of local onset of a COVID outbreak and had a relatively low mortality rate. The assertion was that quick implementation of masks prevented cases from spreading.

The problem with the study is that it was based on data as of May 9, 2020. Since then, the cited European countries have experienced rapid growth in fatalities and are no longer among the countries with low COVID mortality. For example, Czechia is listed as having a fatality rate of 25.8 per million, but by the writing of this article, that had increased to 520 per million in a surge that started in late September. Bosnia and Herzegovina had a similar experience, moving from 31.1 to 520 deaths per million. Moreover, the other countries listed are largely in Africa and East Asia and have generally experienced much lower rates than the rest of the world, for yet to be determined reasons. Meanwhile, other regions, such as South America, have experienced high fatality rates despite having some countries, such as Peru and Argentina, with strict mask-wearing mandates.

In the end, the CDC’s assertion that the cited human studies of masking support the idea that community mask-wearing is an effective strategy against the spread of COVID is unsupported.”

Karl Dierenbach is an engineer-turned-attorney living outside Denver, Colorado. He is also a member of RationalGround.com, a group dedicated to gathering, analyzing, and disseminating information on Covid-19. Follow him on Twitter, @Dierenbach.


I repeat my recommendation to consult with experts (including OSHA-certified trainers) in your jurisdiction to make sure you get this right.

Thank you!

Michael Oswald



Please note: the above post contains educational information. It is not intended as legal advice. Engage an attorney who is licensed in your state to get advice on dealing with any specific legal issue.

© 2020 Michael S. Oswald

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