Let’s start with this fact… All viruses are neither “Living” nor “Dead”… Instead, they are considered to be somewhere in-between these two worlds!!!  This is extremely important when it comes to the “decontamination” and “disinfection” procedures necessary for the prevention of the COVID-19 disease (caused by the SARS-CoV-2 virus) and our current worldwide pandemic. To clarify…  When we are referring to “COVID-19”, as is done frequently in the press, we are technically referring to the actual human disease caused by the SARS-CoV-2 virus.  The acronym, “SARS” refers to a specific designation of this particular classification of  virus that has been shown to cause Severe Acute Respiratory Syndrome (or SARS).   When the term “Coronavirus” is used, we are referring to another particular sub classification (and exterior physical characteristic) of this particular novel SARS type virus.  OK, so I got that out of the way right up front!

What we currently know and understand about the COVID-19 viral disease is changing rapidly. Information associated with the COVID-19 virus is being gathered and distributed quickly by extremely competent and reputable worldwide authorities such as the World Health Organization (WHO) and US Centers for Disease Control and Prevention (CDC) to name only a few. I can say that the absolute best and most brilliant scientists in the world are actively working on this crisis. Much of the latest and updated information associated with the COVID-19 disease and the SARS-CoV-2 virus are widely accessible on the CDC and WHO websites directly. However, there are currently also a number of recognized “gaps” within these published guidelines which are related specifically with the decontamination and disinfection of surfaces as it relates to first responders, law enforcement, fire departments, and others who encounter situations where areas, equipment, workers, and personal protective equipment (PPE) are potentially impacted by COVID-19 surface contamination and residues.

The current guidance and recommendations endorsed by the WHO and the CDC are well publicized and documented and include improved testing to identify impacted areas and communities, social distancing to prevent person-to-person infection, as well as hand washing and general disinfecting methods of surfaces to minimize infective transfer of the “viable” COVID-19 causing virus from surfaces that are contacted. What is missing though, are specific guidance and procedures (with a reasonable explanation) to effectively and efficiently address the decontamination and disinfection of surface areas, equipment, personnel, and PPE. This is where my experience comes in…

I started this Blog discussion clearly stating that viruses are neither “living nor dead”!!! What this means is that we simply cannot “kill” the SARS-CoV-2 virus because it is not technically “alive”… I know this sounds like the “Zombie Apocalypse”, but in a way, that is exactly what this is! To combat this (and to win this battle), our goal then needs to be is to focus on rendering the COVID-19 causing virus “nonviable” on surfaces and within its host. Remember, “nonviable” simply means to render the virus unable to replicate and/or otherwise transfer into a new host (such as another person) where it may then do harm and replicate and transfer again. A forthcoming vaccine that we all hope will be soon-to-come, will address better protecting us from infections in the future, but that vaccine is likely months off at this point. So taking this fight back to this virus by precluding airborne exposures (through social distancing) and eliminating surface contact (through decontamination and disinfection of surfaces) are where we can have a significant effect on the spread of COVID-19.

One of the best analogies that I have heard from a medical doctor is that of the COVID-19 virus using its hosts lung tissue (once infected) as a sort of parasitic “copy machine” which uses the lung tissue to produce billions and billions of copies of itself and redistributes these within the hosts exhaled breath (within tiny aerosol liquid droplets). If inhaled by another individual, these tiny droplet aerosols (containing copies of COVID-19 virus) then may infect a new host where the entire process starts all over again.


Research referenced by the American Industrial Hygiene Association indicated that tiny liquid droplets and aerosols generated by sneezing and/or coughing can remain airborne within a typical room under quiescent (meaning relatively still) conditions for as long as 1.5 hours. Areas which have environments with turbulent airborne conditions (such as more air flow movement) will allow these same airborne droplets and aerosols to remain in the air for much longer and have been even measured (according to the referenced study) for as long as 8 hours. This underscores the need for everyone to limit the transmission and distribution of these droplets from coughing and sneezing wherever possible. If no new host is readily available or present nearby to be “infected”, the tiny aerosol droplets (containing viable virus) may then eventually settle or transfer onto other available surface where they may remain viable (for a yet undetermined time) to then potentially re-infect another host individual. These tiny droplets produced through coughing or sneezing are also referred to as “foamites”. The transfer from surfaces is believed to occur through contact exposure from a person touching a contaminated surface and transfer of the virus containing foamites to the host’s lungs through touching of the face, mucous membranes, and/or other means, which ultimately allows the virus to reach the new hosts’ lungs once again. The range of harm caused by the COVID-19 virus is currently understood to include varying degrees of damage and/or alter the lung tissues of the host throughout the infection period and thereby cause a range of serious adverse metabolic and physical impacts within its host. Another good analogy regarding surface contamination is to think of the COVID-19 as “sticky wet red paint”!!! That is, anyone who has the COVID-19 will be emitting the virus like if they were leaking this liquid red paint that stays “wet” for a number of days. Sounds terrible right? Well, now imagine that this wet red paint is being released by exhaled air by the current host (who may not even be symptomatic) through coughing or sneezing onto to a number of surfaces passed on through contact like onto a table top, a gas pump, a door handle and the like. Now that viral infected “wet red paint” is on these surfaces and ready to transfer onto anyone who touches them. I know that this is an analogy but it seems to get the message across.

Decontamination and Disinfection Considerations:

OK, so let’s now get to some specific details on how to mitigate these hazards when they get onto surfaces… Remember that the success of any decontamination process can be measured by the achievement of the goals that we set, right? Our battle strategy goals are clearly to minimize (or better yet, eliminate) exposures and the resultant spread of COVID-19 causing virus. And our “battle-plan” methods to do this are through the decontamination and disinfection of surfaces potentially impacted by this microbiological “sticky wet red paint”-like contaminant. We are all hearing a number of terms being thrown around in the treatment of surfaces now, which are critically important to understand. These terms include “Decontamination”, “Cleaning”, “Sanitizing”, “Disinfection”, and “Sterilization”. In fact, many times these terms are being used incorrectly as each term represents a vastly different degree of treatment and outcomes using varying methods. For instance, the term, “decontamination” is a very general term that many of us in the field of industrial hygiene use to describe the physical removal of a specific contaminant (such as the COVID-19 causing virus) from a particular surface. The term “cleaning” refers to the visible removal of dirt and debris and has no bearing on removal of invisible microbial bacteriological contaminants such as bacteria or virus that may be present. The term “sanitization” is defined differently in most states and refers to the “reduction” of microbial contaminants and, as such, is a rather loose term at best. The term “disinfection” is defined differently by each state and is generally the 4 to 5 log scale reduction (or “kill” factor) resulting in the 99.99% reduction of viable microbial contaminants. Then there is the term “sterilization” which is the highest level of “kill” and results in the rendering of a surface as virtually free of all detectable viable microbial particles (including virus) or other living organisms on a particular surface or material.

For the purposes of the COVID-19 causing Coronavirus, the CDC recommends that “disinfection” should be considered as the appropriate target for treating surfaces that should be considered. Lets focus on this term in a bit and look at the efficacy of some of the recommended decontamination and disinfection solutions and then on to the application methods that are needed. First though, lets discuss the CDC’s recommendations for washing hands and faces with soap and water… Which is good for the following reasons: As we know, the SARS-CoV-2 virus is in the classification of virus know as Coronavirus. This means that is a virus that consists of a lipid (fat) based envelope material that protects the inner coding which is in the specific form of single stranded Ribonucleic acid (or RNA). This critical inner material is responsible for the coding, decoding, and expression of the viral genes to self replicate and then infect the host. As we all know, most fats and similar materials are readily cleaned (meaning “broken down”) using common detergents like soap, Dawn liquid, Formula 409 and the like. By braking down the Coronavirus lipid fat envelop layer and exposing the interior RNA coding material, it is hoped that the virus will then be unable to reproduce or infect another host. The data is still not available on how effective that soap and water alone is at doing this and is why the CDC and WHO also recommend hand sanitizer (with 60% alcohol) and chlorine disinfection wipes as well. On a side note – a recent finding from the Princess Cruises case was that detectable coronavirus RNA was found present on cabin surfaces within the ship some four weeks now after it was vacated. No one is saying that this RNA was viable or not at this point, but I would not want to be the first to know that it was… by being infected! This is why supplemental disinfection is recommended by the CDC and WHO after soap and water washing.

According to current CDC guidance, solutions that are concentrated alcohol-based and/or solutions which contain adequate levels of chlorine (as noted below) have been shown to be effective in treating COVID-19 causing virus on contaminated surfaces and thereby, rendering the Coronavirus as nonviable so they are unable to replicate and/or infect another host. There are a number of commercially available disinfection solutions and products available which have also been proven to be affective for use as COVID-19 surface treatments. A list of such commercially available products is available on the US Environmental Protection Agency (USEPA) website (dated 3/26/20) and is available at: www.epa.gov/pesticide-registration/list-n-disinfectants-use-against-sars-cov-2. Such products are divided into categories including; ready to use, dilutable, wipes, and other products that have been shown to disinfect against human Coronavirus. Although these commercially available solutions and products listed on the USEPA website are proven effective, in light of limited supplies, it has also been proven that a number of common solutions and products that are readily available for use or ones which we can easily make are also available and include:

1) Alcohol (ethanol or isopropyl alcohol): Solutions consisting of a minimum concentration of 60% alcohol within products used for hand sanitizers or wipes and solutions with minimum concentration of 70% alcohol within solutions intended for spray and/or wipe disinfection methods are proven effective to treat COVID-19 according to the WHO and CDC.

2) Chlorine (Sodium Hypochlorite or also known as common Clorox Bleach): According to CDC and USEPA, chlorine bleach solutions with a mixed concentration made at a minimum 48:1 ratio (48 parts water and 1 part liquid household bleach) concentrate have been shown to be effective in treating Coronavirus impacted surfaces. Since my experience has shown that most hospitals have developed and follow “universal precautions” and require mixtures of closer to 20:1 (20 parts water to 1 part chlorine bleach), I would recommend going closer to these higher concentrations wherever possible. It has also been shown that greater concentrations do not increase effectiveness so I don’t recommend going any grater than 20:1.

Secondly, let’s now explore treatment and application methods that are available and that are shown to work… To this end, l’ll review again how a worker may be exposed to the COVID-19 causing Coronavirus. Primary routes of exposure are currently understood to exist through two main exposure pathways. These include inhalation of liquid aerosols and secondary exposures through physical (dermal) contact with contaminated residues containing viable Coronavirus leading to internal transfer to lungs through means of touching of hands to a hosts’ face/eye/mouth/nose. These exposures are commonly known as secondary “contact transmission” exposures and are known to be alarmingly high with this particular virus for reasons that are not fully understood. Therefore, any reasonably effective disinfection technique designed to clean areas, surfaces, equipment, and workers must also employ aggressive measures designed and planned to minimize or (even better) to eliminate these primary and secondary routes of exposure. In fact, any isolation and/or disinfection strategy such as these, are only as good as the “weakest link” in the chain of procedures and methods employed. Considerations regarding the possibility for cross contamination due to transfer from one surface to another during this (or any) decontamination process is equally as important as the sequence of procedures and methods used. This is why it is so critical to have very clear and direct procedures designed and performed in a specific sequential order for any disinfection strategy to be successful and safe for those who perform them. In fact, I recently prepared such procedures for a local fire department for the disinfection of a fully equipped fire engine (and equipment), which proved to be a very comprehensive task to delineate, prepare, and manage. Such equipment and personnel specific procedures need to take into account the wide variety of surfaces and materials that need to be addressed. For this reason and to be effective, all hard surfaces, semi porous, and porous surfaces, which were potentially impacted, were addressed separately with specific methods (designed for each) considered and thoroughly reviewed and vetted. These included aggressive detergent washing methods followed by alcohol or chlorine solution treatments as a precautionary measure based on what we know currently and have at our disposal. Procedures also included aggressive brush and wipe scrubbing methods and adequate dwell (contact) time depending on the many surfaces addressed. A colleague of mine recently challenged me by asking why the fire truck needed alcohol or chlorine wiping after an aggressive detergent washing based on the discussion of the “lipid envelop” structures (that I discussed previously). Certainly a good (and fair) question to ask. My response was that breaking the “nut” of the coronavirus lipid envelop was good, but to then hit it’s inner belly of RNA again with alcohol and chlorine (which will chemically further break it apart) was another level of safety in the event that areas of the fire truck were not effectively addressed or reached. Since we are dealing with an entirely novel (new) virus that continues to evolve and mutate to survive, my recommendation was to hit it hard versus risk missing the target. Following the CDC and WHO advice is absolutely warranted in my opinion until we learn more.

Remember… in the absence of confirmatory testing of presence (or absence) of COVID-19 virus on such surfaces, we have to assume that viable COVID-19 virus is present. Therefore, it is vitally important that the surfaces are treated using appropriate methods including soap and water as well as disinfectant solutions using aggressive measures, techniques, and protective controls.

Personal Protective Equipment (PPE) Requirements:

Instead of trying to identify a specific regimen of PPE that works for every decontamination situation (which is virtually impossible), I believe that it is better to look at this question in (and from) an entirely different perspective. That is, to select the levels and types of PPE based on the specific activity and tasks that are desired and performed to meet the intended outcome. Since we clearly understand that the primary goal in selection of the PPE regimen is in “protecting” workers and personnel from the COVID-19 virus during a specific set of decontamination and disinfection tasks, we then simply match these task-specific requirements to the potential routes and levels of exposure while performing those tasks. Simple enough, right? Based on everything we know currently, we agree that the greatest exposure potential exists via the primary inhalation route of exposure and that respiratory protection is certainly warranted. The secondary dermal (skin) contact exposure pathway routes which, (as discussed before) can be significant in the form of a variety of potential secondary exposure scenarios such as hand-to-face contact, hand-to-mucous membrane/eye contact, and/or other means by which indirect (and unintentional) lung exposure pathways may then follow and occur. Having an understanding of these independent (yet contributing) exposure pathways leads us to recommend a range of PPE depending on the task and material that is addressed or treated. A typical example of a disinfection process performed on (for example) the fully equipped fire engine truck noted recently included the use of a series of treatments using washing followed by spray solutions of alcohol or chlorine based solutions.

A typical PPE regimen will then include a minimum of a full-face air purifying respirator (APR) or Powered Air Purifying Respirator (PAPR) to protect the lungs and face of the wearer. A chemical resistant hooded coverall like a Tyvek or Saranex suit with booties (and secondary boot covers). And finally hand protection using double-layered nitrile gloves. Use of N95 (or better yet N100) filter face piece respirators may suffice if the potential level of exposures are determined to be minimal based on the activity performed. For instance, use of an N95 or N100 filter face piece is considered best practice for simply wiping hard surfaces in an office area with disinfecting solutions of chlorine or alcohol wetted rags. However, a full face respirator with N100 HEPA filtered cartridges would be prudent for more aggressive disinfection methods such as fogging, spraying, and brushing activities like I have described where the potential for contact with (or generating) liquid droplets aerosols are likely possible.

Also, in addition to any direct disinfection procedure method utilized, it is critical that very well thought out planning, methods, procedures, and sequencing of tasks must occur for an effective and safe process to be successfully performed. Other critical considerations include specific planning to eliminate cross contamination, protection and isolation of materials, and containment of the materials (during the treatment process itself). Specific procedures to handle the waste materials (including used PPE) that will certainly be generated are also an important consideration. These methods and considerations need to be developed and implemented prior to bringing the decontaminated and disinfected equipment and materials back into service for re-use. Remember, the “weakest link” control concept is important during each and every step and stage of this process.

The planning and performance of these procedures is so critical at many stages of the process, in fact. As you can imagine, this is exactly why my many years of professional expertise and experience in decontamination of highly toxic contaminants are so critically useful now with the COVID-19 crisis. As BioMax Environmental’s Senior Certified Industrial Hygienist (CIH), I have been performing toxic contaminant site assessments and overseeing the cleanup and decontamination at sites (both residential and commercial properties) for well over 25 years. In fact, most recently, my assessment and cleanup work with opioid contaminated sites were instrumental in the gathering of verified technical surface concentration data, which ultimately supported the passage of California’s current Methamphetamine and Fentanyl Assessment and Cleanup Act (AB1596). This new California State Law (enacted in 2020) is the first of its kind in the country and includes requirements for the assessment and decontamination of sites contaminated with highly toxic opioid residues such as fentanyl and carfentanil, which are known to be lethal at even the smallest concentrations. As in these decontamination cases, similar “parallel” procedures and controls are equally important and necessary in the decontamination and disinfecting of areas and equipment where COVID-19 causing virus is now considered the contaminant of concern. The sobering aspect of the Coronavirus versus a synthetic man-made chemical like fentanyl though, is that the COVID-19 virus is a biological hazard where (in theory) a single viable virus or less than a micron in size, has the potential to infect and cause severe harm to its’ human host. Of course, Exposures related to concentrations with virus (and other biohazards) is not as simple as other chemical exposures due to many unique factors involved with organisms (like a virus) that can replicate and amplify within its host. The SARS-CoV-2 virus dose-response curve is dependent on (and subject to) this “amplification” effect that is so incredibly complex as we are now seeing. This amplification and transmission is based on many factors such as the individual hosts’ immunological traits, overall health, and susceptibilities where toxicologist professionals are currently unable to determine the NOAEL (No Observed Adverse Effect Level) in such a case based on traditional toxicology. It is simply too variable to do so this way. A contrasting analogy is that of a classical chemical dose-response curve for (let’s say) the chemical compound benzene where the toxicology of this compound that us widely used in industry is very well established clinically. The difference with benzene (being a chemical) as compared to a viral hazard (like the SARS-CoV-2 Coronavirus) is that the virus will replicate itself within the human body unlike the chemical compound. Therefore, a viral compound will effectively increase it’s concentration within the hosts’ body over time and by doing so will increase it’s resultant potential to harm that host. That difference has certainly gained MY attention for sure!

So please remember… we are all in this together and with solid information (and sound specific guidance) we can also get through this pandemic crisis. As BioMax’s Senior Certified Industrial Hygienist (CIH), I am dedicated and committed to the “Science and the Art” of controlling exposures to toxic contaminants that could affect workers, the public, and the environment. As such, my work involved within this new COVID-19 threat is more than professional, it is also personal. Therefore, by writing this informational piece and attempting to answer such common questions and concerns, I hope that this information as general guidance will help those who may benefit from the concepts, topics, and recommendations discussed. For all of the many local authorities, medical facilities, first responders, and police departments who have already used this information and these perspective as a general guide for their heroic daily operations, I offer and encourage any and all to benefit from these recommendations and references.

Thank You and Be Safe,

Michael A. Polkabla, CIH, REA

Senior Certified Industrial Hygienist, Principal

BioMax Environmental, Inc.


(831) 264-3414