Bumping this request for feedback on the use of cloth masks in laboratory spaces. Please limit the replies to best practices for laboratory use of cloth masks and not whether public use is or isn't justified.

My personal opinion is that a lab is very different from a public space and deserves additional consideration. The ventilation is better but there are also additional hazards which probably present a more likely exposure and risk than an asymptomatic labmate..

FYI - OSHA released a guidance document on preparing workplaces for COVID19 https://www.osha.gov/Publications/OSHA3990.pdf

Thought provoking questions

OSHA says surgical masks are a physical barrier. Physical barriers are considered engineering controls. A face shield is also a barrier but it's considered PPE. Is it considered PPE because the individual has to wear it and provides them protection as opposed to a source barrier? If a cloth mask is a physical barrier providing source isolation where does it rank in effectiveness? Is it an engineering control, PPE or something less effective than PPE?

OSHA's enforcement guidance says cloth masks are not ppe. emphasis added.

https://www.osha.gov/memos/2020-04-03/enforcement-guidance-use-respiratory-protection-equipment-certified-under

Using homemade masks or improvised mouth and nose covers only, as a last resort (i.e., when no respirators or facemasks are available). Improvised masks are not personal protective equipment and, ideally, should be used with a face shield to cover the front and sides of the face. When this measure is the only resort, refer to the Centers for Disease Control and Prevention (CDC) guidance at www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/face-masks.html.

For those of you whose institutions have decided to require cloth masks in lab spaces what best practices are you recommending?

• Do you require different masks in lab vs home areas?
• How are you discouraging the mask from becoming contaminated by other lab hazards? e.g. adjusting while wearing contaminated gloves. Are you encouraging people to change them frequently?

If you are not using masks in the labs are you discouraging talking as another means of source control? See https://www.nature.com/articles/s41598-019-38808-z

• speaking (as exemplified by counting aloud) releases about 2-10 times as many total particles as a single cough
  
• droplet nuclei generated by singing is 6 times more than that emitted during normal talking and approximately equivalent to that released by coughing
• counting aloud for 10=E2=80=89seconds followed by 10=E2=80=89seconds of breathing, repeated over two minutes, releases half as many particles as 30=E2=80=89seconds of continual coughing, which in turn releases half as many particles as saying "aah" for 30=E2=80=89seconds.

On an encouraging note, this recent NEJM letter showed an impressive reduction of particles generated during speech while wearing a damp cloth cover in a video clip. Thoughts on why a damp mask was used? Would a dry cover have had the same result?

Or are cloth masks in a lab no big deal and now just a part of our standard attire like a shirt?

It would be helpful if AIHA or ACS could release a statement on the use of cloth masks in laboratories.

Looking forward to your comments,

Anna

On Tue, May 5, 2020 at 12:16 PM LaCroix, Steve (DOH) <Steve.LaCroix**At_Symbol_Here**doh.wa.gov> wrote:

--touche´

Steve

From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of Monona Rossol
Sent: Tuesday, May 5, 2020 9:53 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] [EXTERNAL] [DCHAS-L] Wearing cloth mask in the lab

Of course they don't stop the aerosol. Can't imagine anyone with brains would think a piece of cloth could do this. If it could, we could dump NIOSH certification and buy babushkas. Instead, the DIY masks:

1) reduce exposure of others round you to the big stuff you generate.

2) keep most of the big droplets from landing on surfaces to contaminate others,

3) help remind you, or even prevent you, from touching your nose and mouth,

4) provide a feeling you and those around you are at least doing something, and

5) remind you to stay the hell away from others by 6 feet or more.

The countries that wear masks do better in the numbers game. And it is not from the efficacy of the mask to capture the aerosol.

Monona

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To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Sent: Tue, May 5, 2020 11:42 am
Subject: Re: [DCHAS-L] [EXTERNAL] [DCHAS-L] Wearing cloth mask in the lab

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From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU> on behalf of Yamaira Gonzalez <000003a8c5269e98-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU>
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To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Subject: [EXTERNAL] [DCHAS-L] Wearing cloth mask in the lab

Good morning,

What is the latest about wearing cloth mask while doing lab work? Does anyone know of a good article? Pros and cons.

Regards, yamy

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On Fri, Apr 24, 2020 at 9:27 AM, Stuart, Ralph

<Ralph.Stuart**At_Symbol_Here**KEENE.EDU> wrote:

> In fact, just compiling a list of coronavirus-related issues that should be addressed would be valuable.
>
I'll throw one in: An issue I am concerned about in regard to reopening any public area is the cloth mask protocol. Cloth masks are community health measures rather than personal safety measures, so I would be reluctant to impose OSHA style expectations on the use of cloth masks by the public. On the other hand, I can imagine that these masks are likely to become reservoirs for many contaminants beyond the Covid virus.

I think that we face a major challenge in maintaining the quality of the cloth masks if we ask people to wear them in public areas while relying on the wearers to maintain them. I suspect that professional laundry services will be required to assure co-workers and the community that the masks are being appropriately cleaned.

A related question is: Are labs public areas? Few academic labs I have seen have security protocols that control who enters them and it will take a significant change in both protocol and culture in change this situation.

Thanks for asking an interesting question.

- Ralph


Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859

ralph.stuart**At_Symbol_Here**keene.edu

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Anna Sitek, CSP, CCHO

Research Safety Professional- College of Science & Engineering

Department of Environmental Health and Safety

University of Minnesota- TCEM

Lab Safety Resources www.z.umn.edu/labsafe

Joint Safety Team www.jst.umn.edu

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