Built Environment as a Dangerous Ecosystem

Michael Schrantz^1, John Banta^2, Larry Schwartz^3, David Lark^4,

1. Environmental Analytics LLC, Tucson, AZ
2. Restcon Environmental, Rancho Cordova, CA
3. Safestart Environmental, Buffalo Grove IL
4. NJS Environmental Pty Ltd, Newcastle, NSW, Australia

CORRESPONDING AUTHOR Michael Schrantz [email protected]

OPEN ACCESS

PUBLISHED 31 August 2025

CITATION Schrantz, M., Banta, et al., 2025. Built Environment as a Dangerous Ecosystem. Medical Research Archives, [online] 13(8). https://doi.org/10.18103/mra.v13i8.6767

COPYRIGHT © 2025 European Society of Medicine. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

DOI https://doi.org/10.18103/mra.v13i8.6767

ISSN 2375-1924

ABSTRACT

For millennia, damp and musty buildings have been linked to human illness, as noted in ancient texts, including Leviticus 14. Today, the modern equivalent of priestly oversight falls to Indoor Environmental Professionals (IEPs), who serve as a bridge between clinical understanding and the physical assessment and remediation of structures. This paper—Part B of a three-part series—advances the evolving recognition of the built environment as a medically relevant ecosystem, particularly for individuals with complex chronic illnesses such as Chronic Inflammatory Response Syndrome (CIRS), mast cell activation disorders, and chemical sensitivities. Building on Part A, which outlined the human health impacts of exposure to microbial and chemical agents in water-damaged buildings (WDBs), this paper reframes conventional assessment and remediation practices by introducing a medically important approach for assessing and remedying WDBs, along with measures to prevent future exposure. It emphasizes the inadequacy of superficial or cosmetic repairs when faced with persistent health symptoms, highlighting the need for a more in-depth approach that prioritizes occupant-specific sensitivities, proper removal of microbial sources, and durable restoration practices. Drawing on decades of interdisciplinary field experience, we argue that effective remediation must also extend beyond Mold-centric models and consider the broader microbial and material ecology of the indoor space. Key recommendations include redefining thresholds for cleanliness, integrating environmental and health data in building assessments, and selecting non-sensitizing materials to support occupant recovery. The paper positions the building not merely as shelter, but as a dynamic system whose microbial composition can either impede or facilitate healing. By bridging insights from building science, environmental health, and clinical medicine, this work lays the groundwork for transdisciplinary collaboration. Part C translates these environmental and diagnostic principles into an evidence-based, sequential treatment protocol—the CIRS Protocol—designed to restore health through both environmental correction and biomarker-driven clinical care. Together, this trifecta creates a comprehensive framework for addressing illness rooted in the built environment. In that paper, readers will find a detailed rationale and structure for medically important remediation (MIR), supported by field experience and multidisciplinary research. We conclude that sustainable recovery from environmentally acquired illness requires an integrated, occupant-centered approach that treats the building not only as a source of exposure, but as an active component in the healing process.

Keywords

Built environment, Chronic Inflammatory Response Syndrome, water-damaged buildings, indoor environmental professionals, microbial ecology, remediation

A New Paradigm: Evolving Understanding of Microbial Contamination in Buildings

The History of Water Damage in the Indoor Environment. While the ancient priests of Leviticus once served as both doctors and inspectors, charged with identifying and responding to mold contamination in homes, today’s physicians rarely make house calls. Far from being a new problem, the challenge of unhealthy buildings has shifted frameworks: from ritual impurity to scientific causation, from spiritual discernment to analytical diagnostics. By revisiting these ancient accounts with modern understanding, we see not superstition, but early attempts to protect human health from the invisible threats posed by a compromised indoor environment.

Fast forward several millennia, and our responses have grown more clinical and less reverent. Modern-day mold concerns are often reduced to cost, liability, and cosmetic remediation rather than health outcomes. Reports from building occupants are frequently minimized, especially when contamination is not visible. Too often, people who react to moldy buildings are treated as the problem, rather than the buildings themselves. The need for skilled evaluation of environmental health risks remains. Into that gap have stepped a small group of indoor environmental professionals (IEPs), applying a blend of building science, microbiology, and occupant-centered assessment to identify and address the physical manifestations of mold and water damage by practising medically necessary assessments and Medically Important Remediation.

THE INDUSTRY: 1970S-2000

Beginning in the 1970s, the global energy crisis prompted a shift in construction methods. In the name of energy efficiency, builders began tightening building envelopes, reducing natural ventilation, and adopting new materials that were prone to deficient performance in the presence of incidental moisture. These changes made buildings more vulnerable to mold contamination by trapping humidity, limiting drying potential, and introducing cellulose-rich materials that supported microbial growth. Early building materials—such as lime plaster, old-growth wood, and cement board—tended to resist mold colonization. But more modern assemblies, made with paper-faced gypsum, OSB, and cellulose insulation, retained moisture and offered ample nutrients, accelerating degradation when moisture was introduced. As a result, a new phenomenon began to be witnessed; some human occupants experienced various adverse health symptoms, with nonspecific causes. The recognition of buildings as potential contributors to illness was often labelled broadly as Sick Building Syndrome, characterized by nonspecific symptoms such as headache, fatigue, respiratory distress, and cognitive impairment.

In 1993, the New York City Department of Health released the first US government guidance document addressing mold indoors, focused initially on Stachybotrys chartarum. It recommended remediation if one square foot of visible Stachybotrys growth was present. By 2000, the NYC guidance had been revised to include all mold species. It raised the action threshold to ten square feet—changes that reflected a shift toward broader recognition of risk but also raised concerns about the potential downplaying of non-visible contamination.

In 1999, the American Conference of Governmental Industrial Hygienists (ACGIH) published Bioaerosols: Assessment and Control, a foundational text that acknowledged the role of airborne microbial particles in building-related illness. While it stopped short of defining exposure thresholds, it laid critical groundwork for understanding how occupants can be affected even when mold growth is not readily visible.

The Industry: 2001-Present

The US EPA’s 2001 publication Mold Remediation in Schools and Commercial Buildings reinforced many best practices for containment and cleaning but remained dependent on visible mold area to guide decisions. Like the NYC guidelines, it did not adequately address subvisible levels of contamination, or the health risks posed by fine and ultrafine particles, which can persist long after source materials are removed.

The IICRC S500 and S520 standards, introduced in 1999 and 2003, respectively, further formalized the protocols for water damage restoration and mold remediation. S500 emphasized the importance of drying as the first step in all water damage events. At the same time, S520 began integrating risk-based approaches to remediation, including containment, engineering controls, and reducing, or, as a best practice, recommending against the practice of using antimicrobial biocides in an inappropriate attempt to kill mold.

The first Edition of IICRC S520 (2003) also marked a groundbreaking shift in professional mold remediation. It moved away from relying solely on visible mold area and introduced a tripartite classification, which continues to be used today:

• Condition 1: (normal fungal ecology): an indoor environment that may have settled or airborne mold spores or fragments, or traces of actual mold growth and constituents (e.g., ECM, hyphae, mold fragments), that are reflective of a clean and dry indoor environment.
• Condition 2: an indoor environment including surfaces and air, which is contaminated with residual mold biomass from a known Condition 3 source in that same indoor environment. This includes spores and fragments, filaments, or extracellular matrix (ECM) from sporulation, sloughing, or the production of other compounds (e.g., mycotoxins and microvolatile organic compounds, or mVOCs).
• Condition 3: (actual mold growth): an indoor environment contaminated with the presence of mold growth that is active, dormant, dead, non-viable, visible, or hidden.

This framework rejected the simplistic “size-based” remediation thresholds and acknowledged that microbial contamination is not always visible or active. It underscored a crucial insight: mold spores and fragments can behave like invisible dandelion fluff, released from active growth areas (Condition 3), drifting through air currents, settling elsewhere (Condition 2), and potentially causing health effects, even in spaces with no visible mold.

The importance of this invisible pathway was further explained in, “Modelling the Equilibrium Spore Load of a Building,” which demonstrated mathematically how aerosolized spores reach an equilibrium concentration based on source strength, room volume, airflow, and surface deposition rates and other factors such as filtration, cleaning and tracking of contaminants from the outside. This model demonstrated and offered a scientific basis for why Condition 2 contamination can persist, spread, and impact occupant health even after visible remediation steps are taken.

This has significant clinical implications. Occupants may continue to experience symptoms even after visible mold is removed, due to suspended or settled particulate contamination. Recognizing this, remediation must encompass:

• Identification of hidden mold sources (Condition 3)
• Control of aerosolization during remediation
• Verification of spore and fragment reduction (Condition 2)

These steps are essential to restore a building to a healthy baseline, genuinely—not simply clean it.

As the industry grew, it was not without additional challenges. In the early 2000s, public understanding of mold and its health effects was undermined by the Veritox (formerly GlobalTox) scandal. A paper published in the Journal of Occupational and Environmental Medicine, funded by interests in the insurance industry, claimed that mold exposure posed little to no health risk. The study’s authors failed to disclose financial conflicts of interest, and later testimony revealed that payments had been made. The journal eventually sunsetted the paper, but its conclusions had already been used widely to justify the denial of insurance claims and medical complaints.

Despite this setback, recognition of mold related health issues continued. The Guidance for Clinicians on the Recognition and Management of Health Effects Related to Mold Exposure and Moisture Indoors was developed to support medical professionals in identifying, evaluating, and managing health complaints potentially linked to indoor mold and dampness. The guide began to bridge the gap between clinical presentation and environmental exposure, offering physicians practical tools for patient evaluation, diagnostic considerations, and collaboration with indoor environmental professionals (IEPs). It emphasizes a multidisciplinary approach, recognizing that accurate diagnosis and effective treatment often require both medical insight and a thorough understanding of the patient’s environment.

Around the same period, a breakthrough in mold analysis emerged from researchers at the US Environmental Protection Agency (EPA). Dr. Stephen Vesper and colleagues developed a patented technology, Mold-Specific Quantitative Polymerase Chain Reaction (MSQPCR), to measure DNA from approximately 150 mold species in settled dust, which was published in 2007. This allowed for identification of molds to the species level, regardless of whether they were viable, a feature recommended by both the World Health Organization and the Institute of Medicine urged its development. In addition, this allowed clinicians to identify otherwise viable/non-viable or fragmented mold species (containing related DNA) that may create their unique biotoxins. With the advancements from Next-Generation-Sequencing (NGS) and other methodologies under development, a higher resolution of analysis is becoming available to the practitioner.

By 2006, the S500 achieved American National Standards Institute status with the publication of ANSI/IICRC S500 (3rd Edition, 2006) Standard and Reference Guide for Professional Water Damage Restoration. The third Edition of the S520 achieved ANSI status in 2015, further affirming that remediation targets should aim to restore Condition 2 or 3 spaces to Condition 1 baseline levels. The American National Standards Institute (ANSI) plays a vital role in ensuring that industry standards, such as the IICRC S500 and S520, are developed through a rigorous, consensus-based process. ANSI accreditation affirms that a standard meets key criteria for openness, balance, due process, and public review—elevating its credibility and acceptance. The ANSI/IICRC S520 defines the minimum standard of care but also includes best practices through its use of the word recommended, providing a framework for the more rigorous demands of medically important remediation.

In 2008, the US Government Accountability Office (GAO) recognized indoor mold as a significant health concern, urging better federal coordination and consistent public guidance. The GAO identified several health outcomes associated with mold exposure, including respiratory effects and exacerbation of asthma. However, it noted the need for further research into other potential severe effects, such as pulmonary hemorrhage in infants and immune suppression caused by mold-produced toxins.

The landmark 2009 World Health Organization (WHO) guidelines on indoor air quality (dampness and mold) reinforced the scientific evidence linking dampness, microbial growth, and adverse health outcomes, primarily respiratory symptoms, asthma exacerbation, allergies, and immunological disturbances.

Expanding the clinical perspective, the Chronic Inflammatory Response Syndrome (CIRS) framework, extensively identified and defined by Dr. Ritchie Shoemaker, underscores how water-damaged buildings (WDBs) specifically contribute to systemic inflammatory conditions. According to the 2018 consensus statement, WDBs become harmful ecosystems when biotoxins and inflammagens, produced by molds and bacteria such as endotoxins and actinomycetes, interact with genetically susceptible individuals. The resultant inflammatory response involves complex immunology, coupled with deficiencies in regulatory neuropeptides. This response characteristically leads to a multisystem, multi-symptom illness, often unrecognized by conventional medical assessment.

Building on MSQPCR, in 2016, Dr. Shoemaker, along with David Lark, developed and published the HERTSMI-2 scoring system, using five selected mold species from the Group 1 list (Water Damage indicator mold species) from the ERMI panel, associated with adverse health outcomes in CIRS patients. Its clinical relevance was correlated to CIRS biomarkers in a study involving over 80 patients. Together, these developments reveal a deeper truth: the built environment is not merely a passive backdrop to our lives. It is a living ecosystem—one that can nurture health or undermine it, especially for those who are most vulnerable. Our challenge is to recognize and treat it accordingly.

The Built Environment as a Dangerous Microbial Ecosystem (Biological Focus)

The built environment, especially when compromised by water damage, becomes a complex microbial ecosystem. The proliferation of diverse fungal and bacterial species creates an indoor biome (envirobiome) that can significantly impact human health, particularly in genetically or immunologically susceptible individuals. In such environments, microbial succession, interspecies interactions, and bioaerosol dispersal mimic natural ecological processes, but with elevated human exposure risks due to confinement and chronicity.

Unlike outdoor environments where microbial diversity can often confer resilience and balance, WDBs exhibit a shift towards pathogenic or opportunistic organisms, with diminished protective diversity. The convergence of microbial amplification, decaying building materials, and disturbed ventilation systems exacerbates occupant exposure.

Biophilic design and ecological awareness in architecture are emerging counterpoints to this trend. Yet without rigorous moisture control, adequate remediation, and awareness of microbial dynamics, the built environment continues to present a significant but often invisible threat to health.

Assessment of water-damaged building environment

Limitations of the Visual Inspection Model

The absence of visible mold growth can mislead assessments. The reliance on visual inspection remains one of the most persistent—and problematic—limitations in assessing water-damaged buildings. While visible mold growth is a critical and obvious warning sign, it often represents only the beginning of contamination. Hidden fungal growth, fine particulate residues, and surface-bound microbial fragments can remain even after a building appears visually clean. For individuals suffering from conditions like chronic inflammatory response syndrome (CIRS) or environmental sensitivities, these hidden and non-visible residues can continue to provoke symptoms long after the original moisture problem appears or has been resolved.

Visual inspection is further constrained by how building assemblies conceal microbial contamination. Mold often colonizes interstitial spaces—behind walls, under flooring, above ceilings, and inside HVAC components—where it is inaccessible to direct observation. Moreover, past remodelling or maintenance activities may not only ignore microbial growth but also actively obscure it. For example, replacing drywall or cabinetry without assessing the wall cavities behind them can harbor fungal contamination, though pathways commonly exist allowing these contaminants to enter the living spaces. Painting over visible stains, applying new flooring over water-damaged substrates, or encapsulating attic sheathing without addressing the root cause of growth and source of contamination can often result in additional exposure concerns that are concealed or presented as deceptively clean in appearance while, at the same time, making future investigation and remediation far more complex and often more invasive.

Even more concerning is the widespread tendency to equate “no visible mold” with “no mold problem.” This false reassurance can delay necessary action and lead to premature assumptions that the exposure has been removed. In medically important remediation work, where the goal is not just to remove gross contamination but to restore a healthy living environment, visual inspection is important, but only the beginning. It must be supported by a structured process that considers building history and design, materials utilized, occupant symptoms, and strategically deployed environmental sampling, analysis and interpretation.

To move beyond superficial evaluations, professionals must recognise the inherent limitations of the visual model and adopt an integrative strategy—one that respects both the unique architectural realities and the driving forces that move moisture and hidden contamination into occupied spaces, and ultimately, the clinical consequences of exposure to non-visible residues.

The Medically Important Assessment: Understanding the Building Environment

Contemporary literature and governmental reviews now converge on viewing water-damaged buildings not merely as inconvenient problems of property maintenance, but rather as substantial public health challenges. This recognition calls for improved cross-disciplinary collaboration and rigorous environmental assessment methodologies. In 2016, the Indoor Environmental Professionals Panel of Surviving Mold published a consensus statement regarding medically sound investigations and remediation of water-damaged buildings in cases of CIRS-WDB. More recently, the CIRSx Institute (https://institute.cirsx.com/) expanded upon this advanced approach and created training for IEPs, focusing on Medically Important Assessments. This resulted in a greater understanding and refined treatments to be used in the industry.

A thorough understanding of when performing a building assessment requires a deep understanding of building science fundamentals. A comprehensive evaluation must include air pressure differentials, air movement patterns, and the identification of key pathways through which contaminants may enter the occupied space. As Dr. Joseph Lstiburek of Building Science Corporation accurately emphasizes, air moves from high-pressure zones to low-pressure zones—often dragging with it moisture, particulates, and biological contaminants. This air movement is frequently uncontrolled, driven by various forces, occurring through cracks, wall cavities, ceiling plenums, and other construction voids. Air pressure differentials created from HVAC systems or thermal gradients can draw pollutants from hidden reservoirs into breathing zones. A failure to recognize these pressure-driven flows undermines accurate environmental diagnosis and, subsequently, appropriate remediation planning. Instead of addressing the visible symptoms alone, knowledgeable IEPs must assess how the building functions as a system. This systems-based perspective is essential for identifying how contamination is transported, where it originates, and how it might be effectively identified and properly remediated to protect human health. Part of a thorough assessment will often include the collection of real-time measurements (e.g., Temperature, Humidity, Carbon Monoxide, Carbon Dioxide, Total Volatile Organic Compounds (TVOCs) and chemicals, Particulate Matter (PM)) and environmental (e.g., mold and bacteria) sampling. Often like taking vitals of a patient, these indicators can help shape or reinforce the IEP’s hypotheses of where underlying issues are occurring. Knowing, for example, that a build-up of carbon dioxide (CO2) in the basement of a home, when humans do not occupy the basement, may indicate the presence of amplified microbial growth, or even insufficient ventilation.

Sampling the Unseen: Integrative Use of Advanced Sampling Techniques

Strengths, limitations, and strategic deployment of environmental sampling methods.

Mold (Fungi) For the IEP, they are faced with the fact that all samples inherently are limited. Coupled with the reality that not every mold species can be commercially identified using the available analysis methods, the passionate and informed IEP needs to find methods that offer superior value. Gone are the days of exposure concerns only being focused on viable (“alive”) mold and bacteria. Whether “dead (non-viable)” or “alive” mold, for example, can still cause adverse allergic (inflammatory) responses in individuals. This is of key importance due to the limitations that some forms of mold sampling and analysis (e.g., Microscopy, Culturing) do not identify non-viable mold structures (culturing), nor do they identify fungal fragments, which are another significant source of exposure concern.

While these methods retain value within medically important assessments, it is the responsibility of the IEP to determine when a specific sampling technique is warranted and to interpret the results within the context of each method’s limitations. Just as a cardiothoracic surgeon must weigh the benefits and constraints of various surgical interventions in light of a patient’s medical history and physiological condition, so too must the IEP judiciously apply sampling tools in alignment with the hypotheses developed that focus on the building’s design, environmental history (profile), and clinical needs of the patient.

Failing to recognize this reality of our environment often leads to misdiagnosis of the building. Today’s IEPs, however, have access to incredible advances in field sample collection and analysis since the first microscope was used to analyse mold in 1665 by Robert Hooke, an English scientist. Culturing of mold using a range of selected agar media, for example, allowed for the detection and identification of viable mold (airborne spores containing a nucleate compartment that settle on the chosen agar) to germinate. This result eventually led to enumeration (Colony Forming Units (CFUs), providing additional information to help with the interpretation of this now quantitative dataset.

An acceleration in more sophisticated sampling and analysis techniques were realized in the 1980s to 1990s as concerns regarding “sick building” syndrome and overall “indoor air quality” concerns grew. This included advancements in microscopy (direct examination), the Petri dish (culturable mentioned above), and the development of Mold Specific Polymerase Chain Reaction (MSQPCR) analysis methods, which were eventually commercialized in 2006. A true breakthrough in the industry, MSQPCR uses molecular techniques to detect and quantify mold DNA in a sample. It is extremely sensitive and specific, capable of detecting mold DNA attached to even lesser amounts of mold (“fungal fragments”). Using this technique, IEPs are better equipped to identify what was previously missed completely, yet ever-present in affected buildings.

Historical Background of Interest Despite the scientific strength of MSQPCR, the Environmental Relative Moldiness Index (ERMI), a scoring system which resulted from it, became a source of controversy. Although the original 2007 ERMI paper by Dr. Stephen Vesper and colleagues was epidemiological—intended to establish a quantifiable mold burden index across US homes using data from the American Healthy Homes Survey—it was not designed to support clinical decision-making in individual cases or to serve the diagnostic and forensic purposes outlined in this paper. It was not until 2021 that the US Environmental Protection Agency (EPA) issued a public clarification addressing widespread confusion.

In its bulletin, the EPA confirmed that Mold-Specific Quantitative Polymerase Chain Reaction (MSQPCR) was developed in response to recommendations from the World Health Organization and the Institute of Medicine. It further affirmed that MSQPCR remains the only currently available method capable of identifying molds at the species level, regardless of viability. The EPA clarified that the Environmental Relative Moldiness Index (ERMI), intended for research use only, is a derivative of MSQPCR. This distinction helped restore the scientific credibility of MSQPCR as a valid analytical tool, while also reinforcing the limitations of ERMI as a predictive metric for individual homes.

The value of this method of analysis grew beyond helping diagnose buildings. In 2016, Dr. Ritchie Shoemaker developed HERTSMI-2, a clinically relevant scoring system based on a subset of the ERMI molds. In a study of 807 patients diagnosed with Chronic Inflammatory Response Syndrome (CIRS) related to water-damaged buildings, HERTSMI-2 scores were shown to correlate strongly with symptom expression. This provided physicians and IEPs a practical tool for identifying environments likely to provoke health responses in sensitive individuals, one grounded not just in environmental data, but in patient outcomes.

MSQPCR is also useful for identifying molds that are difficult to culture, or when precise species identification is necessary; an important consideration when recognizing the more traditional methods of sample collection and analysis (e.g., Spore Trap analysis using Microscopy), and some commonly available Petri dish (culture) plates do not speciate. For example, when analyzing a spore trap, the analyst is only able to identify many molds to the Genus level, an obvious and critical limitation. How possibly then, can the IEP conclude that an elevated or atypical concentration of a mold indoors is “normal” as they are not identifying mold to the species level? In a further perversion, Aspergillus/Penicillium cannot be identified even to a Genus level (2 Genera representing >900 individual species) as the spores are small and spherical, lacking distinguishing features. This naturally results in an elevated risk of false negatives. With this knowledge, the IEP, limiting themselves to spore traps collection, are limited by assuming all identified Genera are the same species-when they are not.

Additional Limitations of Spore Traps Spore trap testing, while commonly used in indoor environmental assessments, has several important limitations. It provides only a brief snapshot—typically five to ten minutes—of airborne particulates, and results can be heavily influenced by factors such as human movement, the height of the sampling device, and HVAC system dynamics. Sampling a specific location does not reflect conditions throughout a larger area, and it offers little insight into the location of potential mold reservoirs.

Furthermore, spore trap analysis is limited in precision. It typically identifies organisms only to the genus level, not the species, which precludes any meaningful correlation with mycotoxin production. Analysis of the samples is also prone to human error; the quality of the mycologist will often result in errors in genus identification. Further, the morphology of some genera and species is so alike, so differentiation is not possible (e.g., Aspergillus/Penicillium species vs Trichoderma species).

MSQPCR analysis offers a clear advantage when realizing that this method, this Gold Standard of analysis, also detects the mold DNA associated with ~300-1000 mold fragments that originate from these same species. Peer-reviewed and published papers have documented the superiority of MSQPCR analysis identifying Water Damaged Buildings (WDB) over the more traditional methods outlined above. For the IEP performing medically important assessments, there is no alternative to MSQPCR dust sampling. There are, however, complementary (ancillary) sample collection and analysis methods (e.g., culturing of dust to test for the viability fraction of identifiable species–offering a better idea of whether the source is active or old) that are often utilized, including what is discussed below.

Understanding the influence of outdoor environmental conditions remains critically important. Local and seasonal variations can significantly affect the microbial and particulate background concentrations found indoors, commonly referred to as Condition 1. To appropriately interpret indoor environmental data, the IEP must gather representative outdoor (control) samples. This contextual information is essential for distinguishing between normal background levels and medically relevant contamination during a comprehensive assessment.

In summary, MSQPCR analysis of dust samples stands out as the most precise and clinically relevant method for identifying species-level molds and their associated fragments in water-damaged buildings. Its ability to detect both viable and non-viable material—including hundreds to thousands of microscopic fragments per species—positions it well above traditional methods such as culturing and microscopy in both scope and sensitivity. The peer-reviewed literature strongly supports its application in medically important assessments, where accurate source characterization and exposure potential are critical. While MSQPCR serves as the foundational tool for these investigations, additional sampling approaches—such as culturing for viability—can offer valuable supplementary insights, especially in understanding source activity.

Endotoxins (Gram-negative bacteria)

Water-Damaged Buildings (WDBs) are affected by more than just mold growth. Bacteria are well-documented microbes that occupy adversely affected spaces. Endotoxins produced by gram-negative bacteria are, like mold, ubiquitous outdoors. Yet, a client who has experienced a significant sewage loss in their home would have elevated concentrations of endotoxins indoors. This exposure has been a focus among practitioners for decades.

Endotoxins, components of the outer membrane of Gram-negative bacteria, are potent inflammatory agents capable of triggering a cascade of immune responses in sensitive individuals. When released into indoor environments—particularly water-damaged buildings (WDBs)—these microbial fragments can aerosolize and be inhaled or settle into dust reservoirs. For individuals with Chronic Inflammatory Response Syndrome (CIRS), endotoxins represent a critical exposure concern, as their presence may perpetuate immune activation and contribute to the multisystem symptoms characteristic of the condition.

Unlike mold spores, which can often be detected visually or through DNA-based testing, endotoxins are submicron particles that require biochemical analysis to quantify. The Limulus Amebocyte Lysate (LAL) assay, developed initially to detect endotoxins in pharmaceutical and medical settings has been adapted for environmental testing. This assay uses the blood of horseshoe crabs, which coagulates in the presence of endotoxins, offering a sensitive means of detection. LAL analysis measures endotoxin levels in terms of Endotoxin Units (EU) per milligram of dust or square meter of surface area, providing a valuable metric for evaluating bacterial load and inflammatory potential within the indoor environment.

Historical Background Of Interest

Although the most widely used method for detecting endotoxins has historically been the Limulus Amebocyte Lysate (LAL) assay, derived from the blood of horseshoe crabs, while effective, the process of harvesting LAL involves bleeding live crabs and has become a significant contributor to population declines of these ecologically important species. In response, an alternative method based on recombinant Factor C (rFC) has been developed and is now widely used in Europe. Although rFC has not yet been adopted in the United States due to regulatory lag, its use in environmental applications—such as assessing endotoxin presence in buildings—could provide a more sustainable approach and reduce the ecological burden on horseshoe crab populations.

Several laboratories have integrated the LAL assay into the suite of analytical tools they offer, allowing practitioners to obtain quantifiable endotoxin data from settled dust samples. This methodology offers a non-invasive and extremely sensitive approach for assessing environments where bacterial fragments may be contributing to health issues. By analyzing endotoxin levels alongside mold-specific quantitative PCR (MSQPCR) data, IEPs can gain a more comprehensive understanding of microbial exposures in each space.

Endotoxins originate from a variety of both outdoor and indoor sources. Outdoors, they are commonly associated with agricultural or processing activities, including compost piles, livestock operations, and hay storage, where Gram-negative bacteria proliferate in organic materials. These endotoxins can become aerosolized and infiltrate buildings through open windows, doors, or mechanical ventilation systems. Indoors, common sources include domestic pets (particularly their bedding and skin microbiota), water-damaged materials, HVAC condensate pans and ductwork, as well as improperly cleaned humidifiers, and even kitchen compost bins. Plumbing systems that harbor biofilms, such as P-traps and drain lines, can also emit aerosolized endotoxins under certain conditions. In environments where indoor moisture and organic dust combine, such as bathrooms, kitchens, and utility spaces, the microbial load increases, supporting endotoxin release. Awareness and proper identification of these sources are critical in assessments aimed at minimizing adverse health outcomes linked to endotoxin exposure.

As with sampling the exterior and interior environments for mold, the importance of understanding sources of endotoxins is key. The IEP plays a vital role in locating these sources to provide appropriate remediation or mitigation strategies.

Actinobacteria (Gram-positive bacteria)

Actinobacteria (Actinos), a group of filamentous, Gram-positive bacteria, are increasingly recognized for their role in indoor air quality and potential to exacerbate inflammatory responses in CIRS patients. These organisms thrive in moist, alkaline, cellulose-rich environments common in water-damaged buildings, often cohabiting with mold and contributing to a complex microbiome that challenges conventional assessment strategies. When aerosolized, fragments of Actinos can be inhaled, where they interact with immune receptors and can prompt persistent inflammation. Actinos are also common flora on humans and can become opportunistic pathogens for the susceptible population.

Although historically under-appreciated in environmental testing, Actinobacteria have gained attention due to their detection in case studies involving hypersensitivity pneumonitis and building-related illness. More recent research by Dr. Shoemaker and others has shed additional light on this exposure concern.

Culture-based methods do not easily capture their presence in indoor environment necessitating the use of DNA-based sequencing tools for accurate identification. Advances in environmental genomics, including next-generation sequencing (NGS), have enabled laboratories to quantify Actinobacteria from dust samples with increasing accuracy and clinical relevance.

By combining Actinobacteria DNA data with mold and endotoxin analysis, IEPs now have a more complete microbial profile of an indoor space. This integration allows for improved decision-making in both medical and remediation contexts, particularly when working with individuals with sensitivities. As with endotoxins, recognizing the role of Actinobacteria in environmental exposure helps shift building assessments away from purely visual inspections toward a more biologically driven approach to occupant health.

Non-Traditional Indicators: Odors, Dust Profiles, and Historical Building Use

Looking beyond the typical to identify problems others may overlook. Environmental assessments benefit significantly from looking beyond traditional indicators like visible mold growth or water stains. Non-traditional indicators, such as unusual odors, unique dust profiles, and historical building usage, provide critical insights into hidden contamination and exposure pathways. Recognizing these often-overlooked factors can reveal otherwise unnoticed environmental hazards, particularly valuable for occupants sensitive to subtle microbial or chemical exposures.

Unusual odors frequently serve as early indicators of hidden contamination. Musty or earthy odors can indicate microbial growth in subfloor areas. In contrast, chemical or “off-gassing” odors can indicate VOC emissions from construction materials, cleaning products, or historic use of the building space for industrial or chemical-related activities. IEPs attentive to these odor cues can effectively guide sampling strategies, ensuring targeted evaluations of potentially problematic areas.

Dust profiles also offer substantial diagnostic value. Settled dust acts as a reservoir for microbial fragments, endotoxins, chemicals, and other environmental contaminants. By carefully analysing dust composition—utilising advanced methods such as MSQPCR and LAL assays, assessors can better characterise indoor environments, identify specific exposure risks, and target appropriate remediation actions. Detailed dust profiling frequently uncovers hidden contamination sources, facilitating precise, effective interventions that conventional visual inspections would otherwise miss.

Historical building use is another powerful yet often overlooked indicator. Past uses of a building—such as prior water damage events, historical flooding, previous industrial or agricultural activities, or even past mold remediation efforts—can significantly impact current indoor environmental conditions. Reviewing building histories, maintenance records, and occupant reports helps practitioners contextualize current findings and anticipate hidden or residual environmental risks. Integrating these historical insights with symptom-driven diagnostics and targeted sampling approaches ensures a comprehensive assessment, enabling professionals to identify and mitigate risks effectively.

By embracing non-traditional indicators alongside conventional assessment tools, environmental professionals enhance their ability to diagnose indoor environmental issues accurately. This integrative approach leverages all available clues, ensuring thorough evaluations and improved occupant health outcomes.

Contextual Diagnosis: Occupant Symptoms and Environmental Data

Using patient symptom profiles to inform areas of concern in the built environment. Contextual diagnosis is a crucial aspect of indoor environmental assessments, particularly for occupants experiencing chronic inflammatory response syndrome (CIRS) and other environmentally triggered illnesses. The foundation of contextual diagnosis involves leveraging detailed occupant symptom profiles alongside visual and analytical environmental data to pinpoint areas of concern. Rather than solely depending on visual inspections—which have inherent limitations due to hidden microbial growth and residues—this integrated method provides a more robust and accurate assessment strategy.

Occupant symptom profiles often yield critical insights that can guide the environmental assessor toward specific hidden sources of contamination. Symptoms such as persistent fatigue, cognitive impairment, respiratory distress, and inflammatory responses frequently correlate with unseen microbial contaminants, endotoxins, or volatile organic compounds (VOCs), as well as other stressors emanating from concealed spaces within a building. Recognizing these patterns enhances the effectiveness of targeted sampling strategies, particularly employing the advanced sampling mentioned above, in addition to other techniques such as Interstitial cavity sampling to help locate the specific sources.

By combining patient-reported symptom information with visual inspection results, IEPs can overcome limitations inherent in purely visual assessments. For example, non-intrusive visual inspections alone cannot confirm the presence of mold and endotoxin contamination hidden behind walls, under floors, or within HVAC systems. Importantly, employing contextual diagnosis does not imply that IEPs are making medical diagnoses. Rather, it acknowledges the value of occupant symptom data as an integral component of environmental risk assessment. By complementing environmental assessments with occupant symptoms, IEPs can achieve more precise, meaningful, and actionable remediation plans, enhancing both building health and occupant well-being.

Sequencing Matters: Actions and Recommendations in the Right Order

Effective environmental assessment and remediation depend heavily on proper sequencing. This process typically begins with a thorough intake: collecting the building’s history and understanding the occupant’s health status and symptoms. From this foundation, initial hypotheses are developed and refined during the visual inspection and environmental sampling. Importantly, each phase builds upon the last missteps can result in misinterpretation, wasted resources, and prolonged exposure for sensitive individuals.

For example, recommending HVAC cleaning after whole-home particle remediation can reintroduce contaminants, undermining prior efforts. Similarly, failing to prioritize remediation of a contaminated crawlspace early on can compromise downstream cleaning efforts. Clear, intentional sequencing not only improves outcomes—it respects the client’s time, finances, and well-being.

Recognizing this need, the CIRSx Institute developed the Medically Important Remediation 101 (MIR-101) course, which provides guidance on ordering actions appropriately across the entire project timeline. This approach helps avoid incomplete assessments, premature clearance, or the overlooking of critical reservoirs of contamination.

Nowhere is sequencing more important than during clearance. For clients with case-defined CIRS-WDB, a “safe enough” declaration must be grounded in appropriate metrics. Spore trap testing alone is inadequate; at clinical minimum, post-remediation HERTSMI-2 scores should meet passing thresholds established by experienced clinicians familiar with this illness, though the use of an EPA 36 panel offers 35 additional mold species to provide a significantly better picture of sampled environments to the IEP. This ensures that environmental progress aligns with clinical expectations for recovery. This, combined with a medically important assessment approach, increases the confidence that the building is ready for re-entry.

In summary, following a structured diagnostic and remediation sequence—from intake to final clearance—enhances accuracy, reduces costly redundancies, and provides a defensible framework for protecting both building integrity and occupant health.

Treatment of water-damaged building environments

The Shift from “Remediation” to “Environmental Restoration” For many years, the term “remediation” has served as the industry’s catch-all for the removal of mold and water-damage-related contaminants. But remediation implies the act of correcting a flaw or deficiency. In practice, it often focuses narrowly on the removal of visibly contaminated materials or reducing mold concentrations below visible thresholds. While this may satisfy contractual scope or regulatory guidance, it is increasingly recognized as insufficient when the goal is to create health-supporting indoor environments, especially for sensitive individuals.

Spray & Pray Approach: A Non-Starter Everyone is familiar with the overuse of antibiotics, leading to drug-resistant bacteria. Still, far less attention has been given to the unintended consequences of antimicrobial fungicides used in and on building materials, particularly paints. Dr. Ritchie Shoemaker was among the first to suggest that the fungicide benomyl, incorporated into some paints, may contribute to mutational changes in fungi, leading to more resistant and toxigenic strains.

While authoritative guidance documents have long discouraged the use of chemical biocides for mold remediation, favoring physical removal and source control instead, the allure of a “spray-and-walk-away” solution persists. This ongoing chemical arms race overlooks the fact that simple, non-toxic approaches such as physical removal and cleaning with mild, well-tolerated soaps are both effective, practical, and safer. This is already proving to be true, especially for sensitive individuals, but just like the miners’ canary, all would best heed their warning. By relying on fundamental principles of remediation—source elimination, containment, and thorough cleaning—we can effectively avoid trading one hazard for another.

Environmental restoration, by contrast, implies something more comprehensive. It reflects a growing understanding that buildings function as integrated, dynamic ecosystems. Remediation remains a valuable component, but it’s not enough to remove what is visible; we must also correct the deficiencies that resulted in the original damage and address what is hidden and what is invisible—Conditions 2 and 3—to truly return a space to its intended function. Restoration requires evaluating both the symptoms (contamination) and the causes (building failures), then implementing a plan that returns the structure to a healthful, functional state while minimizing the likelihood of recurrence.

This shift in language mirrors a necessary shift in practice: one that brings together a wider range of disciplines. Medical professionals, environmental consultants, building scientists, restoration technicians, and even architects are increasingly part of the conversation. Their collaboration is crucial—not only for identifying visible mold and damaged materials but for detecting concealed pathways, subvisible particulate loads, and recirculated contaminants that affect air and surface quality.

The cornerstone of environmental restoration is not just identifying causation but fixing the cause. Roof leaks, plumbing failures, negative pressure zones, and vapor intrusion must not only be diagnosed but also permanently corrected. Restoration also means anticipating failure—considering building vulnerabilities like deferred maintenance, aging infrastructure, or poor design—and implementing durable, forward-looking solutions.

This broader approach is especially urgent considering climate change and extreme weather patterns, which increase the frequency and severity of water intrusion events. Buildings must now be evaluated not only for their present condition but also to anticipate their future needs for their resilience in the face of future stressors. In this context, environmental restoration is not a luxury; it is a necessity.

Stepwise Remediation and Commissioning

Meaningful remediation is an important first consideration. It does not occur in a single step. It is a deliberate, multistage process that begins with investigation and progresses through source removal, cleaning, and final verification. This approach, central to both industry standards and field-based frameworks, reflects the evolution from reactionary cleanup toward proactive environmental restoration.

The ANSI/IICRC S520 Standard for Professional Mold Remediation establishes foundational principles for containment, removal of Condition 3 materials, and post-remediation evaluation. However, field experience suggests that these components must be woven into a sequenced strategy—one that addresses not only visible growth but also secondary and subvisible contamination (Condition 2), and that includes corrective actions for both causes and consequences.

A five-stage model has emerged from applied practice to meet these needs. Though structured differently to the S520, it aligns closely with its core concepts and expands them to support building-wide, occupant-centered recovery.

• Stage One: Is There a Problem? This stage involves evaluating building history, occupant symptoms, and visible and non-visible signs of water damage or microbial growth and MSQPCR sampling when hidden conditions are suspected. It reflects S520’s emphasis on initial inspection and condition assessment.
• Stage Two: Develop a Strategy, Team Assembly, and Locating Hidden Problems. Informed by initial findings, this stage includes selecting the right professionals, defining project goals, and using investigative tools to identify concealed contamination and moisture pathways. It echoes S520’s recommendations for qualified personnel and comprehensive project scoping.
• Stage Three: Remediation Planning and Execution. This is where source material removal (Condition 3), particle reduction (Condition 2), and engineering controls are applied. It encompasses many of the procedural elements outlined in S520 but adds greater emphasis on sequencing, health-based decision-making, and adaptive planning.
• Stage Four: Quality Control and Monitoring. Here, environmental sampling, visual inspections, and functional testing are used to determine whether remediation and cleaning goals have been met. This goes beyond basic clearance and incorporates tools such as protein-based assays and occupant reactivity as validation indicators.
• Stage Five: Post-Remediation Reconstruction and Maintenance. This stage reframes rebuilding as an opportunity for environmental restoration, where durable materials, improved ventilation, drainage design, and occupant education are used to reduce future risk. It reflects S520’s call for moisture control and post-project documentation but deepens the long-term preventive framework.

This stepwise methodology bridges the technical rigor of S520 with a holistic restoration philosophy. It recognizes that visible removal is necessary but not sufficient, and that restoring a home to a health-supporting condition involves more than cleanup; it requires prevention, monitoring, and system-level awareness.

By embedding this staged approach within professional practice, remediation shifts from episodic intervention to environmental restoration with lasting impact, especially for sensitive populations.

HVAC and Whole-System Cleaning

In medically important cases, HVAC cleaning must not be seen as optional or secondary—it is central to environmental restoration. Buildings cannot be addressed piecemeal. HVAC systems connect rooms, floors, and materials into a unified network that distributes air—and microbial contaminants—throughout the structure. Cleaning only isolated zones is ineffective and may leave sensitive occupants exposed.

The 2021 NADCA ACR Standard Assessment, Cleaning, and Restoration of HVAC Systems emphasizes this integration. It mandates whole-system inspection and cleaning under continuous negative pressure and requires surface testing through vacuum or visual inspection to verify cleanliness. The standard recognizes that components such as ducts, coils, drain pans, grilles, and blower assemblies must be addressed—especially when conditions indicate microbial contamination (Condition 2 or 3).

HVAC systems often act as microbial reservoirs: spores and hyphal fragments settle on ducts, insulation, and surfaces; when disturbed, they can become re-entrained into the air stream. The NADCA Standard prescribes negative-pressure containment during cleaning to prevent cross-contamination, along with mechanical agitation and HEPA vacuuming to remove settled particulates. Components damaged beyond cleaning—such as porous liner or fragmented coils—must be replaced.

Treating HVAC systems as part of a holistic restoration acknowledges their role both as sources of contamination and as conduits linking all areas of the building. A truly health-supporting remediation considers the system’s capacity to recirculate contaminants, and uses NADCA ACR protocols to clean, test, and document each component. Combining this with surface sampling or particle-counting verification ensures that cleanup extends beyond visual standards and meets the needs of medically sensitive occupants.

Material and Furnishing Considerations

Personal possessions often serve as both reservoirs and vectors of microbial contamination. In water-damaged buildings, the materials that make up furniture, textiles, and household goods can absorb moisture, harbor particulate matter, and amplify exposure risk—especially in homes occupied by individuals with heightened environmental sensitivities. Addressing these items is essential to effective environmental restoration, and yet it remains one of the most overlooked and inconsistently managed aspects of remediation.

To evaluate contents properly, materials must be considered in terms of porosity and cleanability. Non-porous items—such as metal, glass, and some plastics—can often be effectively cleaned using HEPA vacuuming and wiping with a mild detergent solution. Semi-porous items—such as finished wood, sealed surfaces, and some composites—require more nuanced judgment, often based on the integrity of coatings and the water damage exposure history.

Porous materials—including upholstered furniture, books, paper, clothing, mattresses, and unfinished wood—present one of the most complex challenges in Condition 2 environments. While these items do not support active microbial growth unless wet, they can readily collect and retain settled spores, hyphal fragments, and other microbial particles that settle onto them from active growth sites or particle reservoirs elsewhere in the building. However, not all porous materials respond to contamination in the same way, and effective decontamination depends heavily on the type of material, the depth of particulate deposition, and the cleaning methods applied.

Many thin or flexible porous items, such as clothing, bedding, and linens, can often be restored with proper laundering using a well-tolerated detergent. Similarly, individual sheets of paper and the covers of books can frequently be cleaned using dry disposable microfiber wipes, which are effective in removing surface-level spores, particles and fragments without introducing moisture.

Thicker, porous items, such as upholstered furniture, mattresses, and area rugs, require more careful evaluation. If spores and fragments remain on or near the surface, thorough HEPA vacuuming may be sufficient to reduce the particulate load. However, when microbial residues have been ground into the material, for example, through extended use in a contaminated space or repeated pressure and movement, decontamination becomes less reliable. In such cases, the internal padding or substrate may retain particles in a way that makes cleaning inconsistent or unprovable, and disposal may be warranted, especially in homes occupied by sensitive individuals.

Recognizing these material-specific responses is essential in Condition 2 remediation. Decisions about cleaning versus disposal must be guided by cleanability, intended use, and occupant vulnerability—not just by cost or appearance. The goal is not simply to remove visible dust, but to restore materials to a condition that no longer contributes to ongoing exposure.

The ANSI/IICRC S520 Standard recognizes that the ability to restore contents depends on both material type and contamination level. It offers guidance on when porous materials can be cleaned and when they should be discarded, emphasizing the importance of occupant sensitivity, intended use, and potential for re-exposure. However, in medically important cases, these decisions must lean toward conservatism. The burden of proof for retention lies not in aesthetics or monetary value, but in demonstrable cleanability and absence of reactivity.

Contents also complicate remediation logistics. They can obstruct access to structural surfaces, impede airflow during drying, and re-release particles during or after cleaning. Their location, especially when stored in HVAC closets, crawlspaces, or attics, can influence broader building contamination. For these reasons, a systematic content strategy is critical. This includes:

• Sorting items by material type and exposure history,
• Prioritizing cleaning or replacement based on occupant health status,
• Using surface sampling or reactive testing (where applicable) to guide decisions.

In high-sensitivity projects, materials that are visibly clean but chemically or biologically reactive to the occupant may still need to be discarded. Restoration is not about returning contents to a showroom condition; it is about achieving a level of cleanliness that supports recovery and prevents re-exposure.

Patient-Centered Remediation: Balancing Risk, Budget, and Clinical Sensitivity

In conventional mold remediation, decisions are often driven by material costs, insurance policy limits, or what is visibly apparent. But in homes where occupants have medically documented sensitivity to microbial or environmental contaminants, these factors must be secondary to a more urgent priority: protecting health. Patient-centered remediation means customizing the scope, strategy, and endpoints of the project to reflect the clinical realities of the people who will live in the space.

This approach begins by acknowledging that medically vulnerable individuals—particularly those with conditions like Chronic Inflammatory Response Syndrome (CIRS), mast cell activation disorders, or chemically induced hypersensitivity—often react not only to active mold growth but to fine and ultrafine particles, microbial fragments, and even residual compounds absorbed by surfaces or contents. For these individuals, standard visual clearance or generic spore reduction may be inadequate. Even low levels of Condition 2 contamination can be enough to trigger persistent symptoms.

A patient-centered strategy, therefore, requires integrating clinical context into remediation planning. This includes:

• Understanding the occupant’s known triggers (e.g., specific fungal species, VOCs, cleaning agents),
• Communicating with treating physicians or environmental health consultants, when necessary,
• Selecting materials and cleaning methods that avoid sensitizing chemicals,
• And recognizing that “restoration” in these cases means restoring the person’s ability to safely occupy the home, not merely returning it to a standard condition.

Budget considerations remain important, especially when insurance coverage is limited or absent. Patient-centered remediation does not necessarily mean unlimited spending—it means making well-informed trade-offs based on clinical priorities. For example, funds may be better allocated toward comprehensive particle reduction and source isolation than toward aesthetic reconstruction or unnecessary use of antimicrobials.

The ANSI/IICRC S520 Standard recognizes that sensitive occupants require special consideration. It references the importance of pre-existing conditions and the need to adapt work practices accordingly. In medically important projects, this extends to adjusting cleanability thresholds, increasing environmental verification, and accepting that some decisions, such as removing difficult-to-clean but reactive contents, may be guided more by patient history than by visible inspection or microbial counts alone.

Patient-centered remediation emphasizes collaboration over convention. It challenges professionals to listen to the person affected, to understand how their health interacts with their environment, and to use the best available science to make decisions that promote recovery. In doing so, the home becomes not just a cleaned structure, but a sanctuary for healing.

Addressing Condition 2: Cleaning Beyond Visible Growth

Remediation that ends with the removal of visibly contaminated materials does not necessarily result in a health-supporting environment. While Condition 3 contamination, active microbial growth, demands immediate and obvious intervention, Condition 2 contamination often persists long after demolition is complete. Defined by the ANSI/IICRC S520 as the presence of settled spores and fragments originating from growth elsewhere, Condition 2 represents a secondary but clinically relevant form of exposure that is easily overlooked if cleaning stops at visible remediation.

Addressing Condition 2 requires strategies that go beyond conventional construction cleanup. These particles—often too small to be seen—include fungal spores, hyphal fragments, mycotoxins, and other bioaerosol residues that deposit throughout the building. They settle on horizontal surfaces, embed in porous materials, and may be re-aerosolized during occupant activity, HVAC cycling, or airflow changes.

Effective cleaning of Condition 2 environments must rely on a sequenced approach that includes:

• HEPA-filtered vacuuming of hard surfaces and high-dust-load areas,
• Electrostatic microfiber wiping using minimally reactive cleaning solutions (e.g., safe detergents),
• Air washing and misting (when used appropriately) to mobilize fine particles toward surfaces for removal,
• And in some cases, mechanical agitation combined with containment protocols to prevent redistribution.

Importantly, Condition 2 cannot be reliably assessed, or confirmed, or cleared through visual inspection alone. Surface sampling strategies followed by detection with methods such as MSQPCR, protein-based detection methods (e.g., Pathways™ or ATP analogues), or particle count comparisons, pre- and post-cleaning, can help determine whether effective reduction has occurred.

ANSI/IICRC S520 (2015) recognizes the need to clean settled spores and fragments in areas where they may have migrated from original growth sources. It also notes that cleaning methods must be selected based on surface porosity, contamination type, and occupant vulnerability. For medically sensitive occupants, it is often necessary to clean to a health-based outcome, not a cosmetic one.

The process of reducing Condition 2 contamination may also involve cleaning or replacing ductwork, furnishings, and structural components that have acted as long-term particle reservoirs. In such cases, treating the environment holistically—rather than focusing solely on “hot spots”- is essential for ensuring the entire system returns to Condition 1.

Conclusions

Restorative Frameworks for Environmental Health The built environment operates as a living, interacting ecosystem—its materials, airflow, and moisture conditions forming a complex network that can either support or degrade human health. Just as the human body has interconnected systems requiring coordinated treatment, buildings contain subsystems—HVAC, plumbing, wall assemblies, pressure differentials—that must be understood as parts of a whole.

Human Systems Building Systems

• Skeletal Building structure, layout and levels
• Skin Exterior cladding and roofing
• Cardiovascular System air current distribution and supply plumbing
• Respiratory System HVAC System
• Urinary System The drain plumbing system
• Digestive System Building materials degrade via moisture and microbes

Like a skilled physician evaluating organ systems, a trained indoor environmental Professional (IEP) must assess both the symptoms and the root causes, employing a sequence of diagnostic tools and methods that match the complexity of the structure.

Assessment, therefore, is not simply about identifying visible mold or damage. It requires a deeper investigation into subvisible residues, pressure-driven airflow, and occupant symptom patterns to locate and address contaminant reservoirs. The goal is not perfection—no home can or should become a sterile “clean room”—but rather to reduce exposure below the individual’s threshold of sensitivity and to ensure those levels remain stable. This is the essence of environmental restoration: identifying, removing, and preventing the conditions that allow contamination to persist or recur.

With the proper guidance, homes can become health-supporting environments again, even for those with chronic sensitivity.

Bridging Clinical and Environmental Disciplines

Healing requires more than medicine alone. The air and surfaces in any indoor environment host contaminant loads that fluctuate with the presence of sources, the seasons, wind patterns, HVAC dynamics, and even occupancy. The result may be a continued exposure above the reaction thresholds for susceptible occupants. Therefore, proper remediation and environmental cleaning (healing) of the building is also required. If the rate of entry exceeds the rate of detoxification or removal by the clinician, the patient may continue to experience symptoms.

Thus, optimal outcomes demand synchronized efforts between the environmental professional and the treating physician. The IEP must be aware of the clinical context—including symptom triggers, health sensitivities, and recovery timelines—while the clinician must understand the evolving conditions of the patient’s environment. Continuous, informed communication ensures that treatment of the person and treatment of the home evolve in harmony.

Both parties must also avoid overstepping their bounds. Too often, clinicians recommend environmental tests without sufficient knowledge of sampling limitations or interpretation, leading to costly retesting or misguided conclusions. Conversely, IEPs must avoid clinical assumptions outside their expertise. Each discipline must know enough of the other’s science to collaborate meaningfully but defer to the other’s domain. As one author aptly put it, “The clinician and the IEP are like two sides of the same coin.”

Challenges to Mainstream Acceptance

Despite growing clinical recognition, several barriers continue to hinder broader acceptance of environmental restoration as a legitimate health intervention. Skepticism remains widespread—largely because many people have coexisted with some level of visible mold or dampness without acute symptoms. With only an estimated 5–10% of the general population experiencing allergic or inflammatory reactions, most individuals view mold exposure as benign. Yet the science now tells us otherwise: at least 24% of people have a genetic susceptibility to environmentally triggered inflammation. These individuals may suffer severe, life-altering symptoms without ever connecting them to their environment.

Regulatory gaps further complicate the issue. There are few federal or state mandates for mold in public buildings, and airborne contaminant levels can change due to season, weather, or ventilation. Testing methods remain inconsistent, and even certified professionals may have widely different approaches. The presence of unreliable certifying bodies offering minimal qualifications only adds confusion. Encouragingly, movements are underway—some led by nonprofit organizations—to standardize healthy indoor air guidelines and promote legislation, particularly in schools, government offices, and military housing, where Congressional hearings are beginning to address the public health risks involved.

Insurance friction adds a final layer of resistance. Most homeowner policies cover sudden and accidental water damage (e.g., the damage caused by pipe breaks) but exclude microbial growth, structural defects, or long-term wear. While some policies offer limited mold riders, coverage is often inadequate. IEPs frequently serve as intermediaries, delineating between covered water events and uncovered microbial contamination to help adjusters make fair determinations. In some cases, trusted relationships between IEPs and adjusters can lead to more favorable outcomes for the client.

The Hopeful Model: A Treatable System, A Recoverable Patient

What emerges from all of this is a hopeful, actionable model—one in which the building is seen as a treatable system and the patient as a recoverable individual. No environment is completely free of microbial or chemical exposures, nor should it be. A healthy immune system requires some degree of challenge. The goal is not sterility, but balance: to reduce environmental stressors below the patient’s threshold and to keep those levels stable over time.

This is where the expertise of the IEP becomes essential—not just for assessment and diagnosis, but also for interpreting contractor proposals, sequencing remediation efforts, and advising on cost-effective strategies. There must be no conflicts of interest: those who assess the environment should not be the ones remediating it. With proper boundaries and experience, successful outcomes are the norm—not the exception.

Each patient will have a unique recovery path. Some may experience rapid improvement once environmental exposures are reduced. Others may show improvement in lab values (e.g., VCS test scores) before their symptoms resolve. Additional medical issues, detoxification bottlenecks, or stress can all delay recovery, making close coordination between clinician, IEP, and patient essential. Periodic re-testing, maintenance inspections, and appropriate interventions such as air purification or improved ventilation can help keep the space stable and healing ongoing.

Ultimately, the path to wellness is rarely linear—but it is achievable. With commitment, collaboration, and careful attention to both the body and the building, healing becomes not only possible, but probable.