A few weeks ago, Steve and I co-wrote an article about fabric masks for our business partners, Redfora. First, let me say that if you’ve never co-written anything with your partner of seventeen years, maybe don’t wait for a time of at-home quarantine. There were some tense moments, but in the end we were both relatively happy with the final product (noting that the result of the amalgamation of our two voices was a voice that didn’t sound like either one of us, which was weird). I have linked that article again here, as the topic of masks and “how the story keeps changing” keeps coming up..
In response to a query about using vacuum filters for home-made masks, I wrote an addendum, which I will include here, since it wasn’t published with the original article (please read the original article, linked above, first as it provides context for the answer below).
RE: HEPA masks do not have fiberglass
Thank you for pointing this out to us. We should not have implied that all HEPA vacuum filters contain fiberglass, as they do not. HEPA is a designation based on the size of particles a barrier can filter out (specifically they must be able to trap 99.97% of particles that are .3 microns), and that can be done with various materials (please refer to the following Coway Mega article: https://www.cowaymega.com/what-is-a-hepa-filter). There is a fair amount of debate about whether some filters contain fiberglass and if they don’t, does that make a vacuum bag safe to breathe through. There is a great YouTube video from Vacuums R Us that makes a strong argument against the widely circulated belief that vacuum filters contain fiberglass: https://www.youtube.com/watch?v=vmYt_wtaLCk . However, vacuum bags do not list materials (we dug out a few from our front closet and could find no indication of what they were made of), and Vacuums R Us has only been able to get statements from some, but not all, manufacturers about materials in their filters (the ones they have gotten statements from say their filters do not have fiberglass).
Further, Shop Vac, a leading manufacturer of vacuum filters, issued a statement against using vacuum filters in home made masks:
https://www.oregonlive.com/…/is-it-safe-to-make-a-diy-mask-… While this specific manufacturer didn’t refer to fiberglass as the danger, it didn’t list its product’s materials specifically, which implies at the very least that there may be other factors including or besides fiberglass that make the filters dangerous to breathe through, including the manufacturing process.
The ABC News article below, refers to some vacuum filters containing tiny glass fragments, but doesn’t specifically mention which ones. It does, however, caution against using vacuum fibers based Shop Vac’s statement above.
There are a few articles out there that passively recommend that if you use a filter that was not manufactured for filtering breathing, you should couch it in-between layers of other fabric. There is also concern that if a filter is cut to fit into a face mask, it could create particles that may be risky to inhale. As per the New York Times article below: “…if you want to use a filter, you need to sandwich the filter between two layers of cotton fabric…”
The intent of our article was to emphasize the community aspect of fabric mask making and wearing. I know and trust my neighbor Elizabeth. We share many values and points-of-view. She told me she had done research on the vacuum filter issue, and because I have a relationship with her, I didn’t ask for details (though we should have provided them in our article). And while her specific information might not have been wholly accurate (i.e. the fiberglass content) her instincts, in our opinion, were correct. The format of mask she makes (after much trial and error) includes a pocket for some kind of filter, which is left up to the user to decide what goes inside, but she emphatically discouraged me from using vacuum filters based on her own research. If you are making your own masks or are sourcing them locally, please do your own research to determine what you think is safest and best for yourself and your family and then find someone who shares those views and values to source the materials and/or make the masks.
Perhaps more importantly, the point of the public making fabric face masks is not to attempt to re-create the performance of an N-95 mask. As we all well know, these must be reserved for our health care workers who ONLY have a mask and other PPE as a barrier between themselves and highly symptomatic COVID-19 patients. As citizens, we can (and must) use all the tools available to us: physical distancing, hand washing/not touching our faces, AND fabric masks. The masks we make and source locally are meant to reinforce the barrier we are creating between ourselves and others – not to be the only barrier.
We should not have specifically mentioned that people not use HEPA vacuum filters because of the fiberglass not only because it has not been definitively proven but also because it creates a red herring argument. There remains debate about whether all vacuum filters do or do not contain fiberglass (this has not been resolved, though some manufacturers have stated definitively that they do not), but fiberglass content alone is not what determines safety in using a non-medical grade material manufactured for non-medical grade use. In addition, when a manufacturer makes a very clear, very legal-sounding statement against the use of their filters in face masks, pay attention – they are covering themselves for future, unforeseeable problems. It is our opinion that if a filter was not specifically made to filter something you eat or drink (like coffee filters) or put up against your mouth and filter the air you are breathing directly into your lungs, then you should not be using it in your masks. Our times are not so desperate that the short-term risk of COVID-19 infection trumps future potential harm done by using unproven filtration materials for face masks.