(c) 2022 Jon L Gelman, All Rights Reserved.

Wednesday, February 17, 2021

National COVID-19 Aerosol Workplace Standard Urged

Leading public health and workplace safety experts have urged the Biden Administration to invoke immediate measures to reduce the aerosol spread based COVID-19 virus. In a letter to the national pandemic response team leaders, the experts have stated that urgent action is needed on a national scale.

February 15, 2021

Mr. Jeffrey Zients
Coordinator and Counselor to the President COVID-19 Pandemic Response
The White House
1600 Pennsylvania Ave. NW
Washington, DC 20500

Rochelle P. Walensky, MD, MPH
Director, Centers for Disease Control and Prevention 1600 Clifton Road, NE
Atlanta, GA 30333

Anthony S. Fauci, MD
Director, National Institute of Allergy and Infectious Diseases National Institutes of Health
31 Center Dr # 7A03
Bethesda, MD 20892

 Re: Immediate Action is Needed to Address SARS-CoV-2 Inhalation Exposure

 Dear Mr. Zients, Dr. Walensky and Dr. Fauci:

We write as physicians and scientists with expertise in aerosol science, occupational health and infectious disease to commend the Biden Administration’s National Strategy for the COVID-19 Response and Pandemic Preparedness and to urge strong immediate action to strengthen measures to limit inhalation exposure to SARS- COV-2 as a cornerstone of this plan.

 The Biden Administration COVID-19 plan ramps up and expands the availability of life saving vaccines and calls for widespread use of masks, stronger measures to protect workers and updated and more protective guidelines for the public. Importantly, the plan highlights the disproportionate impacts of COVID-19 on Blacks, Latinos and other vulnerable high-risk groups and outlines actions to protect them.

Need for Action

There is a pressing and urgent need for action. COVID-19 infections and deaths recently reached record levels. The roll-out of vaccines that started out in December rocky and slow is now improving, but it will be months before most of the population is vaccinated. In the meantime, more transmissible variants are projected to become the dominant strains by March and may pose significant challenges to the efficacy of first-generation vaccines and monoclonal antibodies. While COVID-19 infections and deaths have started to decline in recent weeks, they remain at a very high level and, unless strengthened precautionary measures are implemented, the new variants will likely bring an explosion in new infections.

 Stronger protective measures are needed immediately to limit exposure and transmission of the SARS-CoV-2 virus to control and end the COVID-19 pandemic. Action is needed to better protect workers and the public against inhalation exposure to the virus. Germany, Austria and France have all recently taken action by mandating respiratory protection equivalent to N95 filtering facepiece respirators (FFRs) and higher quality masks for workers and members of the public and have recommended enhanced ventilation in indoor settings [1–3].

The United States should take similar strong actions to control the COVID-19 pandemic. For many months it has been clear that transmission through inhalation of small aerosol particles is an important and significant mode of SARS-CoV-2 virus transmission. The gravity of this problem was emphasized this week by an editorial in the journal Nature [4]. Numerous studies have demonstrated that aerosols produced through breathing, talking, and singing are concentrated close to the infected person, can remain in air and viable for long periods of time and travel long distances within a room and sometimes farther [5–7]. Gatherings in indoor spaces without adequate ventilation place participants at particularly high risk, an important component of which is driven by asymptomatic and pre-symptomatic viral shedding of infected individuals [8].

 In October, the CDC recognized inhalation as a route of exposure that should be controlled to protect against COVID-19 [9], but most CDC guidance and recommendations have not yet been updated or strengthened to address and limit inhalation exposure to small aerosol particles. CDC continues to use the outdated and confusing term “respiratory droplets” to describe both larger propelled droplet sprays and smaller inhalable aerosol particles. It also confuses matters with “airborne transmission” to indicate inhalation exposure exclusively at long distances and does not consider inhalation exposure via the same aerosols at short distances.

This artificial distinction needs to be replaced with up-to-date terminology [10], as advocated by the National Academies workshop on Airborne Transmission [11], focused on routes of exposure via a) touch, b) large droplets sprayed onto the body, and c) inhalation of small aerosol particles [12].

CDC Guidance Lacking

CDC guidance and recommendations do not include the control measures necessary for protecting the public and workers from inhalation exposure to SARS-CoV-2. Most recommendations from other agencies are also out of date.

For example, CDC continues to recommend surgical masks for most healthcare workers and limits the use of NIOSH-certified respirators only to direct patient care or aerosol generating procedures with COVID-19 patients. It is now well documented that healthcare workers in non-COVID-19 patient care and support positions are also at high risk of infection [13–17] and should be wearing respirators.

Similarly, for non-healthcare workers - even those at very high risk of exposure and infection such as in food processing, prisons and security - CDC and OSHA recommend only face coverings that do not protect against small particle aerosol inhalation. Even the most recent CDC guidelines on face coverings, issued February 11, 2021, focus on prevention of exposure to droplets and state unequivocally “CDC does not recommend the use of N95 respirators for protection against COVID-19 in non-healthcare settings” [18].

CDC has cited shortages of N95 FFRs as a key reason for limiting their use outside of healthcare, but in recent months the supply and availability of these and other NIOSH-approved respirators has increased as new manufacturers enter the market. Millions of NIOSH-approved N95 FFRs are now available and sitting in warehouses, with many employers reluctant to buy from new producers or believing there is no need for their use [19]. Without clear guidance and direction on the need for enhanced protection, there is no demand for these N95 FFRs and some of these new manufacturers may go out of business.

CDC and OSHA must recommend and require the use of respiratory protection, such as N95 FFRs, to protect all workers at high risk of exposure and infection.

CDC and OSHA guidelines fail to follow or recommend an objective risk assessment approach built on well- understood principles, such as exposure being a function of aerosol concentration and contact time or a control hierarchy that emphasizes source and pathway interventions over receptor controls (personal protective equipment). A risk-based control-banding model developed and published by CDC and NIOSH investigators designed specifically for conserving personal protective equipment resources during an aerosol-transmissible infectious disease pandemic [20], updated specifically for COVID-19 [21,22] was not employed and represents a major missed opportunity that could have saved lives.

The failure to address inhalation exposure to SARS-CoV-2 continues to put workers and the public at serious risk of infection. People of color, many of whom work on the front lines in essential jobs, have suffered – and continue to suffer -- the greatest impacts of the COVID-19 pandemic [23,24].

In assuming the directorship of CDC, Dr. Walensky recognized that many of the agency’s recommendations did not reflect the latest science and she committed the agency to reviewing and updating them. On January 20, 2021, Dr. Walensky issued the following statement:

CDC’s Principal Deputy Director Anne Schuchat will begin leading a comprehensive review of all existing guidance related to COVID-19. Wherever needed, this guidance will be updated so that people can make decisions and take action based upon the best available evidence [25].

 We applaud this much-needed focus on science to inform public health guidance and encourage the Administration and its agencies to focus on aerosol inhalation.

To address and limit transmission via inhalation exposure and prevent COVID infections and deaths, we urge the Biden administration to take the following immediate actions:


  Update and strengthen CDC guidelines to fully address transmission via inhalation exposure to small inhalable particles from infectious sources at close, mid and longer range. Updated guidelines should be informed by a risk assessment model that focuses on source and pathway (ventilation) controls first, followed by respiratory protection. Workers in the highest risk categories, including all healthcare workers and other workers with prolonged, close contact with infectious people, must also be provided respiratory protection.

    A year into the pandemic with a re-established supply chain that includes increased US production, CDC must direct healthcare organizations to stop all contingency and crisis practices (e.g. decontamination of N95 FFRs and use of non-respirator face-pieces such as surgical masks in place of respiratory protection), and expand its recommendations for respiratory protection to include all workers in healthcare and related sectors, not just those with direct care of COVID-19 patients.

    Issue an OSHA emergency standard on COVID-19 that recognizes the importance of aerosol inhalation, includes requirements to assess risks of exposure, and requires implementation of control measures following a hierarchy of controls. The standard should address requirements for effective respiratory protection for all healthcare and other workers at high risk of exposure to COVID-19. Workers at lower-exposure risks should be offered high-performing barrier face coverings tested to the ASTM F3502-21 Standard Specification for Barrier Face Coverings with at least 80% filter efficiency, no more than 15 mm H2O air flow resistance and total inward leakage of no more than 5% on a panel of at least 10 subjects.

    Update CDC recommendations and adopt standards for barrier face coverings for the public with high levels of filter efficiency, low breathing resistance and low inward and outward leakage to ensure both source control and personal protection from small particle inhalation, following the test methods described in ASTM F3502-21 Standard Specification for Barrier Face Coverings [26].

    Coordinate a national effort to enhance and distribute the supply of NIOSH-certified respirators and ASTM barrier face coverings for worker protection. Immediately identify existing supplies and help distribute them where they are most needed. Existing supplies of respirators need to be made available and used now, not allowed to sit in warehouses and in supply rooms.

    Use the Defense Production Act to ramp up production of N95 FFRs (particularly models already certified and in wide use), elastomeric respirators, powered air purifying respirators and high-quality barrier face coverings. Provide funding and enter contracts with manufacturers to increase supplies. Coordinate the supply chain and require the purchase of US-manufactured respirators.

 As we have emphasized, immediate action is needed to address inhalation exposure risks in order to bring the COVID-19 pandemic under control. We stand ready to assist the administration in these efforts.

We thank you, President Biden, and the entire administration for your strong leadership and efforts to protect the American public and workers from this deadly virus.


Rick Bright, PhD, Former Director of BARDA, Dept of Health and Human Services

Lisa M. Brosseau, ScD, CIH, University of Minnesota CIDRAP

Lynn R. Goldman, MD, MS, MPH, George Washington University

Céline Gounder, MD, ScM, NYU Grossman School of Medicine & Bellevue Hospital Center

Jose Jimenez, PhD, University of Colorado at Boulder

Yoshihiro Kawaoka, DVM, PhD, University of Wisconsin-Madison and University of Tokyo

Linsey Marr, PhD, Virginia Tech

David Michaels, PhD, MPH, George Washington University

Donald K. Milton, MD, DrPH, University of Maryland

Michael Osterholm, PhD, MPH, University of Minnesota CIDRAP 

Kimberly Prather, PhD, University of California San Diego

Robert T. Schooley, MD, University of California San Diego

Peg Seminario, MS, AFL-CIO (retired)

cc: Marcella Nunez-Smith, MD, MHS, Chair, COVID-19 Health Equity Task Force

James S. Frederick, Principal Deputy Assistant Secretary, Occupational Safety and Health Administration 

John Howard, MD, MPH, JD, LLM, MBA, Director, National Institute for Occupational Safety and Health

Anne Schuchat, MD Principal Deputy Director, Centers for Disease Control and Prevention

Timothy Manning, Supply Coordinator, White House COVID-19 Respons

 Literature Cited

1. Alexa Lardieri. Austria Requires Medical-Grade Masks in Public, Doubles Social Distancing Minimum. US News & World Report 2021; Available at: 25/austria-requires-medical-grade-masks-in-public-doubles-social-distancing-minimum. Accessed 9 February 2021.

2. Henley J, Connolly K, Willsher K, Boffey D. France may follow Germany in making clinical masks mandatory. The Guardian. 2021; Available at: may-follow-germany-in-making-clinical-masks-mandatory. Accessed 9 February 2021.

3. Willsher K. France bans certain homemade Covid masks for use in public. The Guardian. 2021; Available at: Accessed 9 February 2021.

4. Editors. Coronavirus is in the air — there’s too much focus on surfaces. Nature 2021; 590:7–7.

5. Morawska L, Milton DK. It is Time to Address Airborne Transmission of COVID-19. Clin Infect Dis 2020; Available at:

6. Prather KA, Wang CC, Schooley RT. Reducing transmission of SARS-CoV-2. Science 2020; :eabc6197.

7. Prather KA, Marr LC, Schooley RT, McDiarmid MA, Wilson ME, Milton DK. Airborne transmission of

SARS-CoV-2. Science 2020;

8. Letizia AG, Ramos I, Obla A, et al. SARS-CoV-2 Transmission among Marine Recruits during Quarantine.

N Engl J Med 2020; 383:2407–2416.

9. CDC. How COVID-19 Spreads. 2020. Available at: Accessed 9 February 2021.

10. Milton DK. A Rosetta Stone for Understanding Infectious Drops and Aerosols. J Pediatric Infect Dis Soc 2020; 9:413–415.

11. National Academies of Sciences Engineering and Medicine. Airborne Transmission of SARS-CoV-2:

Proceedings of a Workshop in Brief. Washington, DC: The National Academies Press, 2020. Available at:

12. Li Y. Basic routes of transmission of respiratory pathogens—A new proposal for transmission categorization based on respiratory spray, inhalation, and touch. Indoor Air 2021; 31:3–6.

13. Karlsson U, Fraenkel C-J. Covid-19: risks to healthcare workers and their families. BMJ 2020; 371. Available at: Accessed 30 October 2020.

14. Goldberg L, Levinsky Y, Marcus N, et al. SARS-CoV-2 infection among healthcare workers despite the use

of surgical masks and physical distancing - the role of airborne transmission. Open Forum Infectious Diseases 2021; Available at: Accessed 30 January 2021.

15. Nguyen LH, Drew DA, Graham MS, et al. Risk of COVID-19 among front-line health-care workers and the general community: a prospective cohort study. Lancet Public Health 2020; Available at:

16. Iversen K, Bundgaard H, Hasselbalch RB, et al. Risk of COVID-19 in health-care workers in Denmark: an observational cohort study. Lancet Infect Dis 2020; 20:1401–1408.

17. Lan F-Y, Wei C-F, Hsu Y-T, Christiani DC, Kales SN. Work-related COVID-19 transmission in six Asian countries/areas: A follow-up study. PLoS One 2020; 15:e0233588.

18. CDC. Improve the Fit and Filtration of Your Mask to Reduce the Spread of COVID-19. 2020. Available at: Accessed 11 February 2021.

19. Jacobs A. Can’t Find an N95 Mask? This Company Has 30 Million That It Can’t Sell. The New York

Times. 2021; Available at: states.html. Accessed 11 February 2021.

20. Sietsema M, Radonovich L, Hearl FJ, et al. A Control Banding Framework for Protecting the US Workforce from Aerosol Transmissible Infectious Disease Outbreaks with High Public Health Consequences. Health Secur 2019; 17:124–132.

21. Brosseau LM, Rosen J, Harrison R. Selecting Controls for Minimizing SARS-CoV-2 Aerosol Transmission in Workplaces and Conserving Respiratory Protective Equipment Supplies. Ann Work Expo Health 2021; 65:53–62.

22. Center for Infectious Disease Research and Policy. Protecting Essential Workers. Available at: Accessed 11 February 2021.

23. Hawkins D, Davis L, Kriebel D. COVID-19 deaths by occupation, Massachusetts, March 1-July 31, 2020. Am J Ind Med 2021; Available at:

24. Chen Y-H, Glymour M, Riley A, et al. Excess mortality associated with the COVID-19 pandemic among Californians 18–65 years of age, by occupational sector and occupation: March through October 2020. medRxiv 2021; :2021.01.21.21250266.

25. CDC. New CDC Director. 2021. Available at: walensky.html. Accessed 9 February 2021.

26. Subcommittee F23.65. WK73471 New Specification for Barrier Face Coverings. Available at: Accessed 28 January 2021.

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Jon L. Gelman of Wayne NJ is the author of NJ Workers’ Compensation Law (West-Thomson-Reuters) and co-author of the national treatise, Modern Workers’ Compensation Law (West-Thomson-Reuters). For over 4 decades the Law Offices of Jon L Gelman  1.973.696.7900  has been representing injured workers and their families who have suffered occupational accidents and illnesses.

Blog: Workers ' Compensation

Twitter: jongelman

LinkedIn: JonGelman

LinkedIn Group: Injured Workers Law & Advocacy Group

Author: "Workers' Compensation Law" West-Thomson-Reuters