We were preparing to start implementing the Stanford approach using a drying oven at 158F as we do not have the gaseous hydrogen peroxide setup available at SMU and it seemed like the best approach for disinfecting a few dozen masks at
a time. NIOSH however, recommends against dry heat due to degradation of filter media.
Brandon S. Chance, MS, CCHO
Director of Environmental Health and Safety
Southern Methodist University
Duke University Hospitals has developed a very successful method using hydrogen peroxide and have presented a webinar on the method. It has been quite successful and is very well vetted by a highly respected group of industrial hygienists,
virologists, medical doctors, etc.
Please take a listen to their approach (which is in practice today).
S.Z. Mansdorf, PhD, CIH, CSP, QEP
Consultant in EHS and Sustainability
Here’s the eagerly awaited NIOSH document summarizing the current situation. The paper bag method is at the very beginning. Useful tables address the other methods. And there is a warning that none of these methods
is as good as getting a new N95 after each use.
Director of Health, Safety and Environment
“My friends, love is better than anger. Hope is better than fear. Optimism is better than despair. So let us be loving, hopeful and optimistic. And we’ll change the world.”
No. Some disinfectants are toxic if inhaled, they may compromise the integrity of the melt-blown fabric that the facepiece uses, and five days should be enough to sufficiently degrade the virus. However, I was
only reporting what I’ve heard NIOSH is concluding. The guidance document isn’t out yet.
Director of Health, Safety and Environment
“My friends, love is better than anger. Hope is better than fear. Optimism is better than despair. So let us be loving, hopeful and optimistic. And we’ll change the world.”
Maybe spray it with a disinfectant spray before placing in the bag
NIOSH is about to come out with new guidance on disinfection and reuse. As I understand it, the Battelle system will get high marks. And one expedient is to put a used N95 in a paper bag for five days before
reusing it, since there’s pretty fair evidence that the virus will be sufficiently degraded in 2-3 days. We’ve been urging them to say in the guidance that these are stopgap measures, not as protective as getting a new respirator after every use, and only
to be used in a supply crisis.
These are excruciating problems. We’re talking to health care workers every day who are short of not just respirators, but gowns, face shields, booties, gloves. And for their patients the projected shortages
aren’t just beds and ventilators but, in one case, IV tubing. There’s enough blame to go around, but some of it falls on hospital administrators, who take pride in running a hospital “like a business,” and think an MBA outweighs a MPH or MD. And that’s equally
true for the “nonprofit” hospitals. Just-in-time supply works well in an auto plant. Not in a hospital; not in a pandemic.
Director of Health, Safety and Environment
“My friends, love is better than anger. Hope is better than fear. Optimism is better than despair. So let us be loving, hopeful and optimistic. And we’ll change the world.”
I haven't had time to read through the full set of emails on this, so sorry if this is a repeat. Battelle has some basic information on the system on the website.
Sent from my Verizon LG Smartphone
Well, thank you Jack and Stanford. Finally a nice clear presentation on these issues stating what we all probably knew deep in our kishehs. Monona
-----Original Message-----
From: Jack Reidy <jreidy2**At_Symbol_Here**stanford.edu< a="">></jreidy2**At_Symbol_Here**stanford.edu<>
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Sent: Mon, Mar 30, 2020 12:11 pm
Subject: Re: [DCHAS-L] N-95 disinfection and reuse
Research Safety Specialist
Environmental Health & Safety
484 Oak Road, Stanford, CA, 94305
On pages 5-6 there is a good discussion of the various methods that can be used to disinfect N-95s, including a helpful table and references. One refence shows that hot water vapor from boiling
water for ten minutes is an effective decontamination method.
At Yale, we plan to use vaporized hydrogen peroxide to decontaminate and reuse N-95s using the methods described here:
Director, Yale Office of Environmental Health and Safety
