Elastomeric Half Mask Respirator Resources
Elastomeric half mask respirators (EHMRs) are a type of air-purifying respirator and are reusable devices with exchangeable filter elements (cartridges or filters) that may be selected to provide the needed level of filtration (e.g., N95). The facepieces are made of synthetic or natural rubber material that allow repeated cleaning, disinfection, storage, and reuse. EHMRs can be used to protect against gases, vapors, and particles if equipped with the appropriate filters or cartridges. Because the facepiece must form a tight seal against the user’s face, EHMRs require fit testing at least annually.
Learn more about NIOSH’s studies and the EHMR resources available in the sections below.
What are the benefits of EHMRs?
- Replaceable filter elements
- Offers at least equivalent or more protection than N95 filtering facepiece respirators
What are the potential challenges of EHMRs?
- May interfere with communication and downward gaze
- Storage between work shifts
- Needs cleaning and disinfecting
NIOSH is currently conducting several studies related to elastomeric half mask respirators (EHMRs). These studies are summarized below.
JET FIT – Just-in-time Elastomeric Training and Fit Testing
This project aims to test the feasibility of rapidly fit testing and training healthcare personnel to use EHMRs in place of N95 filtering facepiece respirators (FFRs) and other respiratory protection devices (RPDs) during a public health emergency.
NIOSH completed data collection at three acute care hospitals (affiliated with Emory University, Wayne State University, and The University of Texas) between October 2017 and September 2020. NIOSH published early results (two of three hospitals) from this study in March 2020. More complete methods and results are in development by NIOSH.
Outputs from Study:
Training and Fit Testing of Health Care Personnel for Reusable Elastomeric Half-Mask Respirators Compared With Disposable N95 Respirators Pompeii, L A, Kraft, CS, et al. JAMA Research Letter. March 25, 2020.
RESPONSE – Randomized-controlled Elastomeric Studies with PCR technology, to determine disinfection Safety and Effectiveness
The purpose of this project is to identify how effective various disinfectants are at removing microorganisms from EHMRs as well as develop a protocol to train healthcare personnel to use disinfectant wipes to clean these respirators and check the efficacy of the cleaning.
The project is currently underway, and it is being conducted at two acute care hospitals (affiliated with Emory University and The University of Texas).
REUSE – Routine Elastomeric Use and Evaluations in Healthcare
This 3-6 month project will focus on demonstrating how an acute care hospital implements and uses EHMRs including an evaluation of a single disinfection method.
This project is scheduled to begin in early 2021 at three acute care hospitals (Emory University, Wayne State University, and The University of Texas).
Elastomeric Half Mask Respirator Implementation Guides
Two acute care hospitals are developing an implementation guide describing the logistics for how they developed and implemented elastomeric respirator use at their institutions. The hospitals (affiliated with the University of Maryland and the Allegheny Health Network) are experienced EHMR users and currently use elastomeric half mask respirators in healthcare delivery.
This project is currently underway and is expected to be completed by the end of February 2021.
Outputs from Study:
University of Maryland Implementation Guide to Support Use of Elastomeric Half Mask Respirators in Healthcare
Examination of Healthcare Personnel Perspectives and Concerns Regarding EHMR use in a Healthcare Setting and Current EHMR use Strategies due to the COVID-19 Pandemic
Two acute care hospitals (affiliated with the University of Maryland and Allegheny Health Network) will survey and examine healthcare personnel perceptions and concerns from wearing EHMRs. NIOSH expects nearly 1,000 healthcare personnel to be surveyed from these two hospitals.
This project is currently underway and expected to be completed by the end of 2021.
NIOSH Nationwide EHMR Demonstration Projects
NIOSH is continuing to explore strategies to increase the availability of disposable N95 FFRs by leveraging reusable EHMRs and appropriate filter cartridges. The Strategic National Stockpile (SNS) plans to purchase EHMRs and filter cartridges for storage and distribution. NIOSH is assisting the SNS to develop this nation-wide distribution strategy. In collaboration with the SNS, NIOSH prepared a Federal Register Notice to request information from the public regarding the deployment and use of EHMRs in healthcare settings and emergency medical services organizations during infectious disease outbreaks.
To learn more about this effort, please view the Federal Register Notice and archived webinar recording, NIOSH Elastomeric Half Mask Respirator (EHMR) Federal Register Notice Webinar.
Elastomeric Half Mask Respirator and Filtering Facepiece Respirator Exhalation Valve Research Studies
NIOSH is conducting several studies on respirator exhalation valves. Additional information about these studies is available on our Respirator Exhalation Valve Research webpage.
What are Air-Purifying Respirators? (2017)
Understanding the Difference (Surgical masks, N95 FFRs, and Elastomerics) (2019)
Types of Respiratory Protection (2019)
Evaluation of Exhalation Resistance and Inspired Carbon Dioxide Concentration in Elastomeric Half-Mask Respirators with Modified or Covered Exhalation Valves
Though modifying or covering the exhalation valve of an elastomeric half-mask respirator (EHMR) may improve its potential efficacy for source control, it could also result in higher exhalation resistance or elevated concentrations of carbon dioxide gas (CO2) in the respirator facepiece and subsequently increase user discomfort and reduce user acceptance. This study explores two approaches for modifying or covering the exhalation valves of EHMRs: (1) modifying EHMRs to filter the exhaled breath by removing the inhalation valve membranes and blocking the exhalation valve; (2) covering EHMR exhalation valves with surgical masks.
Hospital Respiratory Protection Program Toolkit
This toolkit was developed to assist hospitals in developing and implementing effective respiratory protection programs, with an emphasis on preventing the transmission of aerosol transmissible diseases (ATDs) to healthcare personnel.
Healthcare personnel are paid and unpaid persons who provide patient care in a healthcare setting or support the delivery of healthcare by providing clerical, dietary, housekeeping, engineering, security, or maintenance services. Healthcare personnel may potentially be exposed to ATD pathogens. Aerosols are particles or droplets suspended in air. ATDs are diseases transmitted when infectious agents, which are suspended or present in particles or droplets, contact the mucous membranes or are inhaled.
A Guide to Air-Purifying Respirators
Air-purifying respirators (APRs), such as elastomeric respirators, work by removing gases, vapors, aerosols (airborne droplets and solid particles), or a combination of contaminants from the air through the use of filters, cartridges, or canisters. These respirators do not supply oxygen from other than the working atmosphere, and therefore cannot be used in an atmosphere that is oxygen-deficient or immediately dangerous to life or health (IDLH). The appropriate respirator for a particular situation will depend on the environment and the contaminant(s).
Advancements in Elastomeric Respirator Technology for Use as Source Control
Elastomeric half mask respirators (EHMRs) are being used more widely in U.S. healthcare systems because they can be cleaned, disinfected, and reused. Manufacturers have developed innovative NIOSH-approved EHMR designs that both protect the wearer as well as provide adequate source control.
Understanding respiratory protection options in Healthcare: The Overlooked Elastomeric
In the healthcare industry, the importance of respiratory protection is often overlooked. Choosing the correct respirator for the exposure level and work task is a critical component of a respiratory protection program.
Supplementing the Supply of N95s with Reusable Elastomeric Half Mask Respirators
The high demand and limited supply of N95 FFRs during a public health emergency have led organizations to rely on other types of respirators, such as reusable EHMRs.
Certified Equipment List
The Certified Equipment List is a tool to help respirator users, safety managers, industrial hygienists, and others find NIOSH-approved respirators.
Cleaning and Disinfection Perceptions and Use Practices Among Elastomeric Respirator Users in Healthcare
Hines, SE et al. Workplace Health and Safety
Disinfection of reusable elastomeric respirators by health care workers: A feasibility study and development of standard operating procedures
Bessesen, M. T., Adams, J. C., Radonovich, L., & Anderson, J. (2015). American journal of infection control, 43(6), 629-634.
Elastomeric half mask respirators: An alternative to disposable respirators and a solution to shortages during public health emergencies
Greenawald LA; Haas EJ; D’Alessandro MM. (2021). Journal of the International Society of Respiratory Protection. 2021 Dec; 38(2):74-91
Hospital respiratory protection practices in 6 US states: A public health evaluation study
Peterson, K., Novak, D., Stradtman, L., Wilson, D., & Couzens, L. (2015). American journal of infection control, 43(1), 63-71.
Implementation Guide to Support Use of Elastomeric Half Mask Respirators in Healthcare
Hines S, Thurman P, McDiarmid M. University of Maryland Implementation Guide, February 3, 2021.
Implementation of an Elastomeric Mask Program as a Strategy to Eliminate Disposable N95 Mask Use and Resterilization: Results from a Large Academic Medical Center
Chalikonda S, Waltenbaugh H, Angelilli S, Dumont T, Kvasager C, Sauber T, Servello N, Singh A, Diaz-Garcia R, Journal of the American College of Surgeons (2020)
Implementing Reusable Elastomeric Respirators in Health Care: Considerations for Routine and Surge Use
National Academy of Medicine Consensus Study. Clever, L.H., Rogers, B.M., Yost, O.C., and Liverman, C.T. Editors, The National Academies Press, 2018.
Qualitative Analysis of Origins and Evolution of an Elastomeric Respirator-based Hospital Respiratory Protection Program
Hines, SE, Mueller, N, Oliver, M, Gucer, P, McDiarmid, M. Journal of the International Society for Respiratory Protection. 2017:34:95-111.
Stockpiling supplies for the next influenza pandemic
Radonovich LJ, Magalian PD, Hollingsworth MK, Baracco G. Emerg Infect Dis. 2009;15(6):e1. doi:10.3201/eid1506.081196
Storage and Availability of Elastomeric Respirators in Health Care
Hines, SE, Brown, C, Oliver, M, et al. Health Security. 2019: 17:DOI:10.1089/hs.2019.0039.
Training and Fit Testing of Health Care Personnel for Reusable Elastomeric Half Mask Respirators Compared With Disposable N95 Respirators
Pompeii, L A, Kraft, CS, et al. JAMA Research Letter. March 25, 2020.
User Acceptance of Reusable Respirators in Healthcare
Hines, SE, Brown, C, Oliver, M, Gucer, P, Frisch, M, Hogan, R, Roth, T, Chang, J, McDiarmid, M. User acceptance of reusable respirators in healthcare. American Journal of Infection Control. 2019:47:648-655.
Using public feedback about the use of elastomeric half mask respirators to inform a national deployment study within health settings
Haas EJ; Greenawald LA; Furek A; D’Alessandro MM. (2021). Journal of the International Society of Respiratory Protection. 2021 Dec; 38(2):92-106
CDC—Elastomeric Respirators for U.S. Healthcare Delivery (4/8/2020)
American College of Medical Toxicology (ACMT)—An Alternative to Disposable N95s: The Reusable Elastomeric Half-Mask Respirator Experience (8/19/2020)