By Jeffrey and Grace Stull
In our last column, we attempted to provide up-to-date information to help with the growing confusion about appropriate PPE for first responders involved with incidents with individuals suspected of being COVID-19 positive.
We continue to advocate the use of PPE consistent with evolving Center for Disease Control guidelines, but many jurisdictions struggle with PPE availability, trying to decipher the large number of counterfeit and sometime shoddy products, and also knowing how to clean items that are either intended for reuse and even sometimes disposable products that are not intended for reuse.
In this column, we address the subjects of disinfection, sanitization and decontamination for PPE reuse as departments and organizations attempt to maintain uniform protection capabilities while their PPE supplies diminish or change during the crisis.
Disposable versus reusable PPE
Ordinarily, firefighters wear turnout gear and other types of protective apparel that is relatively rugged for variable response environments. This gear is often intended to last for years when properly cleaned and maintained.
During the COVID-19 pandemic, some firefighters are using single-use or disposable items because it is generally considered safer to simply remove and throw away the items than decontaminate them for reuse. Unfortunately, most organizations are attempting to conserve their disposable PPE, given the uncertainty over supply levels. Further, for many EMS calls, firefighters can’t immediately know a patient’s COVID-19 status, so they have to assume that any individual could be infectious.
Most reusable gear is intended to be cleaned, and for many products, there are well-established procedures for their decontamination. For example, in the most recent revision of NFPA 1851: Standard on Selection, Care and Maintenance of Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting, clear distinctions are made for how different elements of the structural firefighting protective ensemble can be either sanitized or disinfected for neutralizing microbial contamination. In contrast, much disposable clothing has never been intended to be reused because it doesn’t have the physical integrity for repeated use. In those cases where organizations are attempting to decontaminate and reused disposable respirators and clothing, this practice is only as a last resort when no other PPE of the needed type is available.
About disinfectants and sanitizers
It should come as no surprise that the escalated demand for PPE is paralleled by a surging demand for sanitizing and disinfection products.
We have previously written on the topic of understanding the differences between sanitization in disinfection, where disinfection is the near complete inactivation (death) of microbial contamination, while sanitization only achieves a 99.9% effectiveness in reducing bacterial or viral levels on a surface.
The use of disinfectants and sanitizers is now a very important part of the strategies for minimizing cross-contamination that can occur through handling PPE that has been exposed to contaminated aerosols.
The Environmental Protection Agency (EPA) regulates antimicrobial claims and requires that disinfectants (and sanitizers) be registered in that the supplier must demonstrate the effectiveness of its products in reducing specific forms of microbial contamination using specified test methods and particular microorganisms. These qualifications are particularly pertinent now because the EPA has identified several products that are positioned to be effective against SARS-CoV-2, the virus responsible for COVID-19.
Nevertheless, it is important to understand several aspects about these products:
- Disinfectants are considered effective for COVID-19, primarily by showing the ability to work against other hard-to-kill viruses as deemed by the EPA.
- Most disinfectants are for use on hard (non-porous) surfaces, which means that they may not work well on porous materials, such as textiles used in clothing and other forms of PPE. Only those disinfectants that include instructions for use as a laundry additive or presoaking agent should be applied to textile items, and only after it has been determined that those disinfectants will not cause long-term damage to the clothing or other PPE.
- Each EPA-registered disinfectant comes with specific instructions that indicates its use in different applications, be it on a hard surface or other type of product. These instructions include the minimum contact time for disinfection to occur and must be explicitly followed. (Do not follow the practice that “more is better.”)
- There are a range of different active ingredients, some of which are unsuitable for different types of PPE. For example, some disinfectants use bleach or bleach-like chemicals that can potentially damage turnout clothing and other PPE materials. Choose only those disinfectants that can be used as laundry additives or for presoaking. Ensure with the PPE manufacturer that they are safe to use with their product.
In selecting disinfectants, departments obtain a copy of instructions that the supplier used for their EPA registration, which provides the most detailed information. If not provided by the supplier, these can be obtained on the EPA’s Pesticide Product and Label System by searching the product name, supplier name or EPA registration number.
Note: When searching using the registration number, use only the first two parts of that number. EPA registration numbers usually have three parts separated by hyphens. The third part references the supplier. However, disinfectants that have the first two parts as identical are indeed the same product. Many disinfectants are actually the same products that are branded differently or provided by various suppliers with different product names.
Current best practices for disinfecting reusable PPE
Firefighters who are deploying reusable PPE, particularly respirators, need to follow appropriate cleaning and disinfection procedures to adequately remove contamination threats and maintain the product’s performance for its intended service life.
Many departments have chosen to use elastomeric half face piece respirators or use adapters for their SCBA full face pieces to couple with P100 cartridges. The CDC recently released detailed guidance for the disinfection of these products.
Many respirator manufacturers provide detailed recommendations for their products that often specify disinfection approaches that work, and those that don’t or that destroy their product. In all cases, the process begins with having trained, competent individuals performing these functions in a designated area who are outfitted with gloves, a protective apron or similar apparel, and face shield. For the most part, these procedures include the elements of first removing the cartridges or filters, then cleaning the face piece, followed by its disinfection, rinsing and air drying. It is important to follow the manufacturer instructions and, if not sufficiently detailed, to instead rely on the guidelines provided by OSHA.
As indicated above, appropriate EPA-registered disinfectants should be used as recommended by the respirator manufacturer. It is further critical that the filter media for these respirators not be wetted or subjected to a liquid disinfectants. For this reason, it is best to use filters that have a hard casing that can be wiped down by germicidal wipes. Unprotected disc or “pancake” filters should be avoided. CDC has not established any definite guidance the how many times filters can be used. Some manufacturers recommend changing after each use while others claim that as long as filters are not damaged, breathing resistance through the filter does not increase, and the filter media is not directly soiled, they can be repeatedly reused.
Reusable face shields and goggles should be cleaned, disinfected and air-dried using a similar set of instructions as applied to respirators. These items are generally easier to clean, but like respirators, care should be taken in selecting a disinfectant. Moreover, textile straps associated with goggles or certain respirators have to be considered since these materials are porous and may require different disinfection procedures.
Procedures for the sanitization of turnout clothing are provided in NFPA 1851. The appendix of that standard (Section A.7.4) describes three approaches involving:
- Putting clothing in a soak tank with a solution of an EPA-registered disinfectant and water for an extended dwell time (up to 1 hour);
- Using a sanitization cycle in conjunction with programmable washer/extractor; and
- Using a process that includes the injection of ozone.
Specific to COVID-19 exposures, these procedures must be coupled with advanced cleaning that is performed AFTER the sanitization step, with the exception of ozone, which may occur any time during the cleaning process.
It is further recommended that the advanced cleaning step be replaced with specialized cleaning where the maximum wash temperature can be increased from 105 degrees F to 140 degrees F. Normally, wash temperatures are set the lower temperature due to potential concerns for applying higher wash temperatures, which are believed by some industry to cause earlier damage to clothing over the long term when applied repeatedly.
Other fire-resistant clothing can be handled in the same way as turnout clothing absent specific cleaning and sanitization instructions from the manufacturer.
According to the CDC, general contaminated clothing should not be shaken but instead specially handled and laundered using the warmest possible wash temperature. It is generally advisable to use a standard laundering sanitizer additive in washing clothing. It is interesting to point out that for reusable healthcare linens, the CDC recommends using wash temperatures as high as 160 degrees F for at least 25 minutes in combination with dilute bleach; however, these conditions would damage many forms of protective clothing.
It would be ideal if some form of field disinfection could be used between calls. This capability would allow end-users to continue to wear PPE without concerns for cross-contamination and extend the use of the PPE. Unfortunately, several types of testing must be carried out to validate this approach:
- Testing must demonstrate that selected disinfectants cannot damage or compromise the performance of PPE based on repeated use.
- It must be shown that the process of applying the disinfectant in the field is effective in reducing microbial contamination to safe levels.
- It must be demonstrated that residual levels of disinfectant don’t remain in the clothing that can potentially cause skin irritation or other harmful effects.
Research is underway to determine specific field disinfection approaches, but for now, there is no available evidence for their effectiveness.
Addressing disinfection of disposable products
Attempting to reuse single use products – certain respirators, masks, face shields, and coveralls or gowns – goes against their intended disposability. Some of these products are simply too frail for repeated use. Others break down in cleaning and disinfection process.
According to the CDC and primarily aimed at healthcare providers, decontamination of PPE is current limited to only N95 filtering face piece respirators and disposable face shields – and then only if no other alternatives exist to provide needed PPE.
Based on research that investigated these practices for N95 respirators, only certain approaches will work. The CDC has identified vaporous hydrogen peroxide, ultraviolet germicidal irradiation, and moist heat as the most promising disposable respirator decontamination methods. However, some of these methods are not easily carried out. For example, only certain types of equipment are capable of providing UV irradiation at the right wavelengths and energies for a sufficient time to be considered effective in disinfecting these respirators. The application of moist heat using special techniques with a decided microwave appears to be most accessible form of decontamination.
Even more important is recognizing approaches that don’t work or destroy the respirations, which is a longer list that includes using autoclaving, dry heat, isopropyl alcohol, soap, dry microwave irradiation, bleach, and disinfecting wipes. Learn more from the CDC here.
For disposable face shields, some of the same processes can be used that use of reusable eye and face protection, though the differences will be that the disposable products will break down rapidly from both repeated use and cleaning/disinfection and that certain materials common in disposable face shields, namely the elastic band and foam piece on the head rest, do not disinfect as easily as the hard surface of the plastic lenses.
Currently, there are no recommended CDC guidelines for the use of other disposable items, particularly gowns and coveralls. While it may be possible to use a gentler process, such as a soak tank followed by rinsing, the understanding for the effectiveness for these practices is unknown both for continued performance of the product and the ability to achieve sanitization or disinfection.
It is now known that COVID-19 has certain longevity on different surfaces, including cloth and plastics, where materials that resemble disposable clothing and other PPE can retain infective virus for several days following initial contamination. Based on this information, some believe that simply allowing extended periods of time between using items would warrant a form of disinfectant as virus contamination dies being outside of a host. While this may be a viable practice, and perhaps the only approach possible for some, it is not with risk and would require careful management of the PPE.
In sum: What we know about disinfection
In a perfect world, supplies of disposable PPE would meet first responder and healthcare demands. We clearly know that this is not possible, and shortages demand other solutions, often turning to reusable and available products that then need to be disinfected between uses.
There are options for accomplishing this as an extra step to reprocess the item to a safe level, but with additional time and resource commitments. Key among these is the appropriate use of disinfectants, sanitizers and related processes appropriately applied that do not damage the PPE from frequent use. Further, disposable PPE is not intended for reuse, and disinfection methods can only be applied sparingly and using some very specific procedures that often are not commonly available.
We believe that the reality of the current situation and how it may evolve into the future, even anticipating future pandemics, is a renewed consideration of reusable PPE products that are coupled with viable cleaning/disinfection processes to sustain their long-term use and availability when needed.
For more information
We work with Dr. Christina Baxter of Emergency Response TIPS, where collectively several white papers and quick reaction guides have been compiled during the current pandemic.
About the Authors
Jeffrey and Grace Stull are president and vice president, respectively, of International Personnel Protection, Inc. They are members of several NFPA committees on PPE as well as the ASTM International committee on protective clothing. Mr. Stull was formerly the convener for international work groups on heat/thermal protection and hazardous materials PPE as well as the lead U.S. delegate for International Standards Organization Technical Committee 94/Subcommittees on Protective Clothing and Firefighter PPE. They participate in the Interagency Board for Equipment Standardization and Interoperability and have authored the book, "PPE Made Easy.”