thesynergist | NEWSWATCH
Study: Portable Air Cleaners Reduce Exposure to Simulated SARS-CoV-2 Aerosols
The use of portable high-efficiency particulate air (HEPA) cleaners within a room significantly reduced occupants’ exposure to simulated SARS-CoV-2 aerosols, according to a study discussed in CDC’s Morbidity and Mortality Weekly Report (MMWR) on July 9. While supplementing building ventilation systems with HEPA units was already known to help reduce the number of airborne infectious particles indoors, this study found that using HEPA air cleaners close to an aerosol source—in this case, a simulated SARS-CoV-2-infected meeting participant—reduced the exposure of simulated uninfected participants in the room by up to 65 percent. Researchers found that the reduction in exposure varied based on the placement of HEPA units within the simulated meeting room, and exposure could be further reduced by up to 90 percent by universal masking of meeting participants. The study involved four manikins and two HEPA units placed within a meeting room. One of the manikins was designed to emit aerosols, mimicking an infected meeting participant exhaling SARS-CoV-2 particles into the room. The other three mimicked uninfected meeting participants inhaling the potentially infectious aerosols. Two HEPA units meeting EPA’s recommended clean air delivery rate were placed at various locations in the room, and researchers measured the units’ effectiveness at removing exhaled aerosols for each location. Depending on the location, the HEPA units reduced participants’ exposure by 49 to 65 percent. The most effective arrangement was found to be placing both units on the floor at the center of the room, as opposed to the units being elevated, placed at the front or back of the room, or placed to participants’ left or right when facing the front of the room. Additionally, the study found that the use of masks on all the manikins, without air cleaners, reduced uninfected participants’ exposure by 72 percent. The combination of masking with the use of HEPA units reduced exposure by up to 90 percent. These findings suggest that both masking and the use of air cleaners can significantly reduce SARS-CoV-2 exposures, with the greatest reduction in exposure occurring when both measures are used together. The MMWR report further discusses several limitations of the study. First, the air in the room used for the study was well mixed, improving the transfer of aerosol particles to the HEPA units by air currents. The report explains that aerosol dispersion in any room depends upon air currents unique to each setting, varying by room dimensions and ventilation rates, so air cleaners may be less effective at reducing exposures in rooms with poor air mixing and stagnation zones. Next, the study did not reflect every potential configuration of infected and uninfected occupants in real-world settings. In this study, one simulated infectious aerosol-emitting manikin remained in one location, but an infected individual may move around the room or multiple infected people may be present. Finally, the study only assessed aerosol exposure—not disease transmission. The authors conclude that while the study provides useful information on the effectiveness of HEPA air cleaners, “many other factors are also important for disease transmission, including the amount of virus in the particles, how long the virus survives in air, and the vaccination status of the room occupants.” For more information, refer to the full report.
NIOSH to Examine the Needs of Underserved PPE Users
NIOSH seeks information on needs and challenges related to the use of personal protective equipment among U.S. worker populations who are underserved regarding PPE use, availability, accessibility, acceptability, or knowledge. NIOSH’s National Personal Protective Technology Laboratory (NPPTL) will consider the needs of these PPE user populations, which include workers who are of an atypical size; who are members of a gender, racial, ethnic, or linguistic minority group; who conduct non-traditional activities; or who are members of sub-disciplines that are not the primary focus of the current PPE activities within their field. NIOSH encourages feedback and insights from individuals and organizations with direct knowledge about research, service, or policy gaps affecting these worker populations and those who advocate for these groups. Letters containing information about this topic were due Aug. 23, 2021. For more information, see the notice in the Federal Register.
NIOSH Report Focuses on Developing OELs, OEBs for Engineered Nanomaterials
A new draft technical report published by NIOSH describes the agency’s proposed approach to developing occupational exposure limits (OELs) or occupational exposure bands (OEBs) for engineered nanomaterials. According to NIOSH, the publication is intended as a resource for risk management decision-making to protect workers from potential exposures to engineered nanomaterials. Specifically, the report seeks to cover state-of-the-science approaches for developing categorical OELs or OEBs for engineered nanomaterials that lack sufficient experimental data to develop substance-specific OELs. The agency’s report focuses on the assessment of typical microscale airborne particles and engineered nanomaterials by possible health impact and explores how engineered nanomaterials can be grouped into categories based on the degree to which their effects may harm worker health.
The report is divided into two parts: the first part, the user guide, focuses on tools for gathering and assessing information on OELs or bands for engineered nanomaterials, while the second part outlines the development of the methods for grouping engineered nanomaterials. Part II of the report also discusses the technical basis for the categorical OELs or OEBs described in Part I, the user guide. NIOSH describes the target audience of the report as occupational safety and health practitioners, including industrial hygienists, who use scientific information and tools to assess workplace safety and health.
NIOSH opened a comment period ending Sept. 13 for stakeholders and others to review and provide feedback on the draft report. A notice in the Federal Register provides a full list of questions for those reviewing the draft report, which can be downloaded as a PDF.
FDA Revokes EUAs for Certain Respirators, Decontamination Systems
The U.S. Food and Drug Administration has revoked its Emergency Use Authorizations (EUAs) for non-NIOSH-approved disposable respirators and decontamination and bioburden reduction systems. According to FDA, these actions are consistent with CDC recommendations from May 2021 that urge healthcare facilities to stop using crisis capacity strategies and “promptly resume conventional practices,” including the use of only NIOSH-approved respirators where needed. FDA’s EUA revocations also align with OSHA’s new emergency temporary standard for healthcare settings, which requires employers to provide NIOSH-approved or FDA-authorized respirators for workers who are potentially exposed to COVID-19. A letter to healthcare personnel accompanying FDA’s recent announcement recommends that healthcare workers “transition from extended use of disposable respirators to single-use for single-patient interactions as appropriate.”
According to Suzanne Schwartz, a director in FDA’s Center for Devices and Radiological Health, “access to domestic supply of disposable respirators continues to significantly improve” and the United States’ “national supply of NIOSH-approved N95s is more accessible to [its] healthcare workers every day.”
The revocation of the EUAs for imported, non-NIOSH-approved disposable filtering facepiece respirators (FFRs) such as KN95s and for non-NIOSH-approved disposable FFRs manufactured in China became effective on July 6. FDA’s revocation for the decontamination and bioburden reduction system EUAs for personal protective equipment is effective as of June 30. See FDA’s announcement for further details.
OSHA Resource Summarizes PPE Information for Emergency Workers
A new pamphlet (PDF) published on OSHA’s website summarizes information about personal protective equipment for emergency response and recovery workers responding to events such as natural disasters, accidental releases, and incidents related to biological hazards or terrorism. OSHA stresses that while PPE can help minimize workers’ exposure to hazards, it should be the “last line of defense” following engineering and administrative controls. The pamphlet describes the role of PPE, steps for employers to develop a disaster-specific health and safety plan, and worker safety practices.
The document outlines the four levels of emergency response-type PPE, which ranges from Level A, the most protective, to Level D, the least protective. Level A PPE provides the highest level of respiratory, skin, and eye protection, while level D includes only minimal skin protection.
The agency also offers more detailed information on PPE for emergency response and recovery workers on its website.
EPA Webinar Explored Use of Sprayers, Foggers to Disinfect Surfaces
On July 15, EPA hosted a webinar on COVID-19 research related to the use of electrostatic sprayers and foggers to disinfect surfaces. According to the agency, the risk of SARS-CoV-2 infection from surfaces remains low, but business owners, mass transit leaders, and others still need ways to disinfect large areas—including high-touch and complex, intricate surfaces—quickly and effectively. EPA explains that the use of these methods to apply disinfectants has “increased substantially” during the COVID-19 pandemic.
EPA researchers evaluated several types of electrostatic sprayers and foggers for parameters such as spray charge, droplet size, and disinfection efficacy. Two speakers from the agency discussed the methods and results of this research. Presenters included Joseph Wood and Matthew Magnuson, both with EPA’s Center for Environmental Solutions and Emergency Response. Wood’s research focused on the development, testing, and evaluation of technologies for decontaminating materials contaminated with biological agents and biotoxins. Magnuson is involved in programs related to the analysis and environmental fate of chemical, biological, and radiological contaminants.
A closed-captioned recording of the webinar is available on EPA’s YouTube account.
New NIOSH Page Discusses PFAS Exposures, Research
A new NIOSH workplace safety and health topic page focuses on per- and polyfluoroalkyl substances (PFAS), a group of synthetic chemicals used in many industry and consumer products, including firefighting foam, paints, personal care products, construction materials, and industrial processing aids. According to NIOSH, exposure to PFAS has been linked to cancer and other harmful health effects, and workers in certain industries may have higher exposures than the general public. Chemical manufacturing workers, firefighters, and ski wax technicians are among the occupations that are known to be more exposed to PFAS. Such workers may be exposed by touching concentrated products or by breathing PFAS in the air at their workplace, NIOSH explains.
NIOSH’s new page provides information on risks to workers, collects additional resources on PFAS, and discusses agency research related to PFAS exposures in the workplace. Current NIOSH research activities are focused on exposure and health assessments in manufacturing workers, service sector workers, and firefighters; dermal absorption assessments, sampling and analytical methods, toxicity testing in animals, and high-throughput screening in vitro studies; and firefighter turnout gear testing for PFAS in textiles.
View the new topic page on NIOSH’s website.
EPA Announces Policy Changes, Upcoming Actions for Chemical Risk Evaluations
A press release published by EPA on June 30 describes policy changes and planned actions related to the first 10 chemicals to undergo risk evaluation under amended Toxic Substances Control Act legislation. The changes and actions concern personal protective equipment, risk management, unreasonable risk determinations, and exposure pathways.
As amended by the Frank R. Lautenberg Chemical Safety for the 21st Century Act, which was signed into law in June 2016, TSCA required EPA to complete risk evaluations for 10 chemicals—1,4-dioxane, the cyclic aliphatic bromide cluster (HBCD), pigment violet 29 (PV29), 1-bromopropane, asbestos, carbon tetrachloride, methylene chloride, N-methylpyrrolidone (NMP), perchloroethylene, and trichloroethylene—within three to three-and-a-half years. EPA intends to revisit the assumption in its final risk evaluations for these chemicals that PPE is always provided to workers and worn properly in occupational settings. According to the agency, data on PPE use violations suggest that this assumption is not justified.
The agency’s announcement also mentions a new “whole chemical approach,” which EPA describes as “[making] the determination of unreasonable risk just once for [a] whole chemical when it is clear the majority of the conditions of use warrant one determination.” The agency will seek public comment on this new approach, which differs from the method used by the previous administration in which separate unreasonable risk determinations were made for every condition of use for the first 10 chemical risk evaluations conducted under TSCA.
Lastly, EPA intends to expand its consideration of exposure pathways for the first 10 risk evaluations and develop a screening-level approach to conduct ambient air and surface water assessments for communities near industrial facilities.
Additional information regarding chemicals undergoing risk evaluation under TSCA can be found on the agency’s website.
OSHA to Assess COVID-19 Standard Each Month
A statement posted to OSHA’s website in July says the agency has reviewed the latest guidance, science, and data on COVID-19 and has consulted with the Centers for Disease Control and Prevention through NIOSH regarding the requirements of its COVID-19 emergency temporary standard for healthcare settings, which went into effect on June 21. OSHA’s COVID-19 ETS webpage states that the agency “has determined that no changes to the ETS are necessary at this time.”
“Neither CDC’s guidance on healthcare settings nor the underlying science and data on COVID-19 in healthcare settings has materially changed in a way to necessitate changes in the health and safety requirements contained in the ETS,” OSHA’s website states.
The agency intends to monitor and assess the need for changes to the ETS on a monthly basis.

Two petitions seeking federal court review of OSHA's ETS have been filed by labor organizations, as described in an article published on July 14 by The National Law Review. The lawsuits argue that the rule's application to healthcare settings is too narrow. As of the date that this issue of The Synergist went to press, employers had until July 21 to comply with all requirements of the ETS.