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Executive Summary A damp spot appears in a ceiling after an intense rainstorm; a hose loosens from a washing machine, spilling gallons of water onto a basement floor; weeks after a moldy odor is detected, a plumber finds a slow leak behind a wall. There are over 119 million housing units in the United States and nearly 4.7 million commercial buildings (U.S. Census Bureau, 2003), and almost all of them experience leaks, flooding, or other forms of exces- sive indoor dampness at some time. Excessive indoor dampness is not by itself a cause of ill health, but it is a determinant of the presence or source strength of several potentially problematic exposures. Damp indoor environments favor house dust mites and microbial growth, standing water supports cockroach and rodent infes- tations, and excessive moisture may initiate chemical emissions from build- ing materials and furnishings. Indoor microbial growth--especially fungal growth--has recently re- ceived a great deal of attention in the mass media. It is a prominent feature of the breakdown of dampness control; its many possible causes include a breach of the building envelope, failure of a water-use device, and excessive indoor water-vapor generation. Occupants, health professionals, and oth- ers have wondered whether indoor exposure to mold and other agents might have a role in adverse health outcomes experienced by occupants of damp buildings. Prominent among these health outcomes is acute idio- pathic pulmonary hemorrhage in infants, cases of which were reported in Cleveland, Ohio in the 1990s. Residence in homes with recent water dam- 1

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2 DAMP INDOOR SPACES AND HEALTH age and in homes with visible mold (including Stachybotrys chartarum) was among the risk factors identified in the case infants. Against that backdrop, the Centers for Disease Control and Prevention (CDC) asked the Institute of Medicine to convene a committee of experts. CDC provided the following charge to that committee: The Institute of Medicine will conduct a comprehensive review of the scientific literature regarding the relationship between damp or moldy indoor environments and the manifestation of adverse health effects, par- ticularly respiratory and allergic symptoms. The review will focus on the non-infectious health effects of fungi, including allergens, mycotoxins and other biologically active products. In addition, it will make recommenda- tions or suggest guidelines for public health interventions and for future basic science, clinical, and public health research in these areas. FRAMEWORK AND ORGANIZATION Figure ES-1 describes the path by which water or moisture sources may lead to excessive indoor dampness and to exposures that may result in adverse health outcomes. The elements of this framework are reflected in the major topics addressed in the report: How and where buildings become wet, the signs of dampness, how dampness is measured, the risk factors for moisture problems, and what is known about their prevalence, severity, location, and duration (Chapter 2). How dampness influences indoor microbial growth and chemical emissions, the various agents that may be present in damp environments, and the influence of building materials on microbial growth and emissions (Chapter 2). The means available for assessing exposure to microorganisms and microbial agents that occur in damp indoor environments (Chapter 3). The experimental data on the nonallergic biologic effects of molds and bacteria, including the bioavailability of mycotoxins and toxic effects seen in cellular (in vitro) and animal (in vivo) toxicity studies of mycotoxin and bacterial toxin exposure (Chapter 4). The state of the scientific literature regarding health outcomes and indoor exposure to dampness and dampness-related agents (Chapter 5). Dampness prevention strategies, published guidelines for the removal of fungal growth (remediation), remediation protocols, and research on the effectiveness of various cleaning strategies (Chapter 6). The public health implications of damp indoor environments and the elements of a public health response (Chapter 7). The committee faced a substantial challenge in conducting its review of these topics--research on fungi and other dampness-related agents is bur-

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EXECUTIVE SUMMARY 3 External Internal sources sources of of water or water or moisture moisture Accident or breakdown of one or more elements that determine whether water or moisture sources result in excessive indoor dampness (component failure; poor building design, construction, operation, or maintenance; occupant behavior) Excessive indoor dampness Enhanced environment New or enhanced Dampness-related for house dust mites, growth of mold and degradation of building cockroaches, etc. other microbial agents materials and furnishings Removal processes (ventilation, filtration, surface cleaning, etc.) that affect indoor pollutant concentrations in air or on surfaces and the magnitude of potential exposures Potential exposure of occupants to microbial and other dampness-related agents Other causes Health No change in of health outcome(s) occupant health outcomes possibly related status to exposures Intervention--elimination of moisture source(s); remediation; building renovation; changes in building operation, maintenance and/or occupant behavior ? Reduction or elimination of any health outcomes related to dampness-related exposures FIGURE ES-1 A framework describing the potential for water and moisture sources to lead to excessive indoor dampness and to exposures that may result in adverse health outcomes. geoning, and important new papers are constantly being published. Al- though the committee did its best to paint an accurate picture of the state of the science at the time its report was completed in late 2003, it is inevitable that research advances will extend beyond the report's findings.

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4 DAMP INDOOR SPACES AND HEALTH The sections below are a synopsis of the committee's major findings and recommendations, and the research needs they identified. Chapters 2 7 detail the reasoning underlying these and present the committee's com- plete findings. THE COMMITTEE'S EVALUATION Damp Buildings The term dampness has been used to define a variety of moisture prob- lems in buildings, including high relative humidity, condensation, water ponding, and other signs of excess moisture or microbial growth. While studies report that dampness is prevalent in residential housing in a wide array of climates, attempts to understand its scale and significance are hampered by the fact that there is no generally accepted definition of damp- ness or of what constitutes a "dampness problem." There is no single cause of excessive indoor dampness, and the primary risk factors for it differ across climates, geographic area, and building types. Although the prevalence of dampness problems appears to increase as build- ings age and deteriorate, the experience of building professionals suggests that some modern construction techniques and materials and the presence of air-conditioning also increase the risk of dampness problems. The preva- lence and nature of dampness problems suggest that what is known about their causes and prevention is not consistently applied in building design, construction, maintenance, and use. One consequence of indoor dampness is new or enhanced growth of fungi and other microbial agents. The fungi have (eukaryotic) cells like animals and plants, but are a separate kingdom. Most consist of masses of filaments, live off of dead or decaying organic matter, and reproduce by spores. Visible fungal colonies found indoors are commonly called mold or sometimes mildew. This report, following the convention of much of the literature on indoor environments, uses the terms fungus and mold inter- changeably to refer to the microorganisms. Mold spores are regularly found in indoor air and on surfaces and materials--no indoor space is free of them. There are a large number of species and genera, and those most typically found indoors vary by geo- graphic area, climate, season, and other factors. The availability of mois- ture is the primary factor that controls mold growth indoors, since the nutrients and temperature range they need are usually present. While much attention is focused on mold growth indoors, it is not the only dampness- related microbial agent. Mold growth is usually accompanied by bacterial growth. Some research on fungi and bacteria focuses on specific compo-

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EXECUTIVE SUMMARY 5 nents that may be responsible for particular health effects: spores and hy- phal fragments of fungi, spores and cells of bacteria, allergens of microbial origin, structural components of fungal and bacterial cells, and such prod- ucts as microbial volatile organic compounds (MVOCs) and mycotoxins. Release of these components varies, depending on many physiologic and environmental factors. Dampness can also damage building materials and furnishings, causing or exacerbating the release of chemicals and non- biologic particles from them. Given the present state of the literature, the committee identified several kinds of research needs. Standard definitions of dampness, metrics, and asso- ciated dampness-assessment protocols need to be developed to characterize the nature, severity, and spatial extent of dampness. Precise, agreed-on defini- tions will allow important information to be gathered about the determinants of dampness problems in buildings and the mechanisms by which dampness and dampness-related effects and exposures affect occupant health. More than one definition may be required to meet the specific needs of health researchers (epidemiologists, physicians, and public-health practitioners) in contrast with those involved in preventing or remediating dampness (archi- tects, engineers, builders, and those involved in building maintenance). How- ever, definitions should be standardized to the extent possible. Any efforts to establish common definitions must be international in scope because exces- sive indoor dampness is a worldwide problem and research cooperation will promote the generation and dissemination of knowledge. Research is also needed to better characterize the dampness-related emissions of fungal spores, bacteria, and other particles of biologic origin and their role in human health outcomes; the microbial ecology of build- ings, that is, the link between dampness, different building materials, mi- crobial growth, and microbial interactions; and dampness-related chemical emissions from building materials and furnishings, and their role in human health outcomes. Studies should be conducted to evaluate the effect of the duration of moisture damage of materials and its possible influence on occupant health and to evaluate the effectiveness of various changes in building designs, construction methods, operation, and maintenance in re- ducing dampness problems. Increased attention should be paid to heating, ventilation, and air conditioning (HVAC) systems as a potential site for the growth and dispersal of microbial contaminants that may result in adverse health effects in building occupants. And research should be performed to develop designs and construction and maintenance practices for buildings and HVAC systems that reduce moisture problems; building materials that are less prone to microbial contamination when moist; and standard, effec- tive protocols for clean-up after flooding and other catastrophic water events that will minimize microbial growth.

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6 DAMP INDOOR SPACES AND HEALTH Exposure Assessment The lack of knowledge regarding the role of microorganisms in the development and exacerbation of diseases found in occupants of damp indoor environments is due largely to the lack of valid quantitative expo- sure-assessment methods and knowledge of which specific microbial agents may primarily account for the presumed health effects. Very few biomarkers of exposure to or dose of biologic agents have been identified, and their validity for exposure assessment in the indoor environment is often not known. The entire process of fungal-spore aerosolization, transport, depo- sition, resuspension, and tracking--all of which determine inhalation expo- sure--is poorly understood, as is the significance of exposures to fungi through dermal contact and ingestion. There are several methods for measuring and characterizing fungal populations, but methods for assessing human exposure to fungal agents are poorly developed and are a high-priority research need. Part of the difficulty is related to the large number of fungal species that are measur- able indoors and the fact that fungal allergen content and toxic potential vary among species and among morphologic forms within species. In addi- tion, the most common methods for fungal assessment--counting cultured colonies and identifying and counting spores--have variable and uncertain relationships to allergen, toxin, and irritant content of exposures. Based on their review of the literature, the committee recommends that existing exposure assessment methods for fungal and other microbial agents be subjected to rigorous validation and that they be further refined to make them more suitable for large-scale epidemiologic studies. This includes stan- dardization of protocols for sample collection, transport of samples, extrac- tion procedures, and analytical procedures and reagents. Such work should result in concise, internationally accepted protocols that will allow mea- surement results to be compared both within and across studies. The committee also identified a need to develop improved exposure assessment methods, particularly methods based on nonculture techniques and techniques for measuring constituents of microorganisms--allergens, endotoxins, (13)-glucans, fungal extracellular polysaccharides, fungal spores, and other particles and emissions of microbial origin. These needs include further improvement of light and portable personal airborne ex- posure measurement technology, more rapid development of measure- ment methods for specific microorganisms that use DNA-based and other technology, and rapid and direct-reading assays for bioaerosols for the immediate evaluation of potential health risks. Application of the im- proved or new methods will allow more valid exposure assessment of microorganisms and their components, which should facilitate more- informed risk assessments.

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EXECUTIVE SUMMARY 7 Because only sparse data are available on variation in exposure to biologic agents in the home environment, it is not possible to recommend how many samples should be taken to produce an accurate assessment of risk-relevant exposure. Toxic Effects of Fungi and Bacteria Although a great deal of attention has focused on the effects of bacteria and fungi mediated by allergic responses, these microorganisms also cause nonallergic responses. Toxicologic studies, which examine such responses using animal and cellular models, cannot be used by themselves to draw conclusions about human health effects. However, animal studies are im- portant in identifying hazardous substances, defining their target organs or systems and their routes of exposure, and elucidating their toxicokinetics and toxicodynamics, the mechanisms that account for the biologic effects, metabolism, and excretion of toxic substances. Animal studies are also useful for generating hypotheses that can be tested through studies of hu- man health outcomes in controlled exposures, clinical studies, or epidemio- logic investigations, and they are useful for risk assessment that informs regulatory and policy decisions. Research reviewed in Chapter 4 shows that molds that can produce mycotoxins under the appropriate environmental and competitive condi- tions can and do grow indoors. Damp indoor spaces may also facilitate the growth of bacteria that can have toxic and inflammatory effects. Little information exists on the toxic potential of chemical releases resulting from dampness-related degradation of building materials, furniture, and the like. In vitro and in vivo studies have demonstrated adverse effects--includ- ing immunotoxic, neurologic, respiratory, and dermal responses--after ex- posure to specific toxins, bacteria, molds, or their products. Such studies have established that exposure to microbial toxins can occur via inhalation and dermal exposure and through ingestion of contaminated food. Animal studies provide information on the potency of many toxins isolated from environmental samples and substrates from damp buildings, but the doses of such toxins required to cause adverse health effects in humans have not been determined. In vitro and in vivo research on Stachybotrys chartarum suggests that effects in humans may be biologically plausible, although this observation requires validation from more extensive research before con- clusions can be drawn. Among the other research needs identified in the chapter is further development of techniques for detecting and quantifying mycotoxins in tissues in order to inform questions of interactions and the determination of exposures resulting in adverse effects. The committee also recommends that animal studies be initiated to evaluate the effects of long-term (chronic)

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8 DAMP INDOOR SPACES AND HEALTH exposures to mycotoxins via inhalation. Such studies should establish dose- response, lowest-observed-adverse-effect levels, and no-observed-adverse- effect levels for identified toxicologic endpoints in order to generate infor- mation for risk assessment that is not available from presently-available studies of acute, high-level exposures. Human Health Effects Associated with Damp Indoor Environments The committee used a uniform set of categories to summarize its con- clusions regarding the association between health outcomes and exposure to indoor dampness or the presence of mold or other agents in damp indoor environments, as listed in Box ES-1. The distinctions among categories reflect the committee's judgment of the overall strength, quality, and per- suasiveness of the scientific literature evaluated. Chapter 1 details the meth- odologic considerations underlying the evaluation of epidemiologic evidence and details the definitions of the categories. BOX ES-1 Summary of the Categories of Evidence Used in This Report Sufficient Evidence of a Causal Relationship Evidence is sufficient to conclude that a causal relationship exists between the agent and the outcome. That is, the evidence fulfills the criteria for "sufficient evi- dence of an association" and, in addition, satisfies the following criteria: strength of association, biologic gradient, consistency of association, biologic plausibility and coherence, and temporally correct association. Sufficient Evidence of an Association Evidence is sufficient to conclude that there is an association. That is, an asso- ciation between the agent and the outcome has been observed in studies in which chance, bias, and confounding can be ruled out with reasonable confidence. Limited or Suggestive Evidence of an Association Evidence is suggestive of an association between the agent and the outcome but is limited because chance, bias, and confounding cannot be ruled out with confidence. Inadequate or Insufficient Evidence to Determine Whether an Association Exists The available studies are of insufficient quality, consistency, or statistical pow- er to permit a conclusion regarding the presence of an association. Alternatively, no studies exist that examine the relationship.

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EXECUTIVE SUMMARY 9 Tables ES-1 and ES-2 summarize the committee's findings. The conclu- sions are not applicable to persons with compromised immune systems, who are at risk for fungal colonization and opportunistic infections. Conclusions regarding exposure to agents associated with damp indoor environments are limited by the means used to assess exposure in the epide- miologic studies reviewed by the committee. For the most part, studies have relied on occupants' observations of the presence of "mold" or "moldy odor." Relatively few research efforts have used trained observers or mea- surements to attempt to discern which microbial agents are present, the extent of their growth, or whether there are specific common potential exposures (other than dampness). When the committee is drawing a conclu- sion about the association between exposure to a damp indoor environ- ment and a health outcome, it is not imposing the assumption that the outcome is necessarily a result of exposure to a particular mold or to microbial agents in general. In some circumstances, a paper addresses the association between a particular indoor dampness-related exposure and a health outcome. However, even in those cases, it is likely that people are being exposed to multiple agents. The committee has drawn conclusions about the state of the scientific literature regarding associations of health outcomes with two circumstances: TABLE ES-1 Summary of Findings Regarding the Association Between Health Outcomes and Exposure to Damp Indoor Environmentsa Sufficient Evidence of a Causal Relationship (no outcomes met this definition) Sufficient Evidence of an Association Upper respiratory (nasal and throat) tract symptoms Wheeze Cough Asthma symptoms in sensitized asthmatic persons Limited or Suggestive Evidence of an Association Dyspnea (shortness of breath) Asthma development Lower respiratory illness in otherwise-healthy children Inadequate or Insufficient Evidence to Determine Whether an Association Exists Airflow obstruction (in otherwise-healthy persons) Skin symptoms Mucous membrane irritation syndrome Gastrointestinal tract problems Chronic obstructive pulmonary disease Fatigue Inhalation fevers (nonoccupational exposures) Neuropsychiatric symptoms Lower respiratory illness in otherwise-healthy adults Cancer Acute idiopathic pulmonary hemorrhage in infants Reproductive effects Rheumatologic and other immune diseases aThese conclusions are not applicable to immunocompromised persons, who are at increased risk for fungal colonization or opportunistic infections.

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10 DAMP INDOOR SPACES AND HEALTH TABLE ES-2 Summary of Findings Regarding the Association Between Health Outcomes and the Presence of Mold or Other Agents in Damp Indoor Environmentsa Sufficient Evidence of a Causal Relationship (no outcomes met this definition) Sufficient Evidence of an Association Upper respiratory (nasal and throat) tract symptoms Wheeze Asthma symptoms in sensitized asthmatic persons Cough Hypersensitivity pneumonitis in susceptible personsb Limited or Suggestive Evidence of an Association Lower respiratory illness in otherwise-healthy children Inadequate or Insufficient Evidence to Determine Whether an Association Exists Dyspnea (shortness of breath) Skin symptoms Airflow obstruction (in otherwise-healthy persons) Asthma development Mucous membrane irritation syndrome Gastrointestinal tract problems Chronic obstructive pulmonary disease Fatigue Inhalation fevers (nonoccupational exposures) Neuropsychiatric symptoms Lower respiratory illness in otherwise-healthy adults Cancer Rheumatologic and other immune diseases Reproductive effects Acute idiopathic pulmonary hemorrhage in infants aThese conclusions are not applicable to immunocompromised persons, who are at increased risk for fungal colonization or opportunistic infections. bFor mold or bacteria in damp indoor environments. exposure to a damp indoor environment, and the presence of mold or other agents in a damp indoor environment. As already noted, the term dampness has been applied to a variety of moisture problems in buildings. Most of the studies considered by the committee did not specify which agents were present in the buildings occupied by subjects, and this probably varied between and even within study populations. The committee found sufficient evidence of an association between exposure to damp indoor environments and some respiratory health out- comes: upper respiratory tract (nasal and throat) symptoms, cough, wheeze, and asthma symptoms in sensitized asthmatic persons. Epidemiologic stud- ies also indicate that there is sufficient evidence to conclude that the pres- ence of mold (otherwise unspecified) indoors is associated with upper respi- ratory symptoms, cough, wheeze, asthma symptoms in sensitized asthmatic persons, and hypersensitivity pneumonitis (a relatively rare immune-medi- ated condition) in susceptible persons. Limited or suggestive evidence was found for an association between exposure to damp indoor environments and dypsnea (the medical term for

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EXECUTIVE SUMMARY 11 shortness of breath), lower respiratory illness in otherwise-healthy children, and the development of asthma in susceptible persons. It is not clear whether the latter association reflects exposure to fungi or bacteria or their constitu- ents and emissions, to other exposures related to damp indoor environ- ments, such as dust mites and cockroaches, or to some combination thereof. The responsible factors may vary among individuals. For the presence of mold (otherwise unspecified) indoors, there is limited or suggestive evidence of an association with lower respiratory illness in otherwise-healthy children. Inadequate or insufficient information was identified to determine whether damp indoor environments or the agents associated with them are related to a variety of health outcomes listed in Tables ES-1 and -2. In- cluded among these is acute idiopathic pulmonary hemorrhage in infants (AIPHI). The committee concluded that the available case-report informa- tion constitutes inadequate or insufficient information to determine whether an association exists between AIPHI and the presence of Stachybotrys chartarum or exposure to damp indoor environments in general. AIPHI is a serious health outcome, and the committee encourages the CDC to pursue surveillance and additional research on the issue to resolve outstanding questions. The committee considered whether any of the health outcomes listed above met the definitions for the categories "sufficient evidence of a causal relationship" and "limited or suggestive evidence of no association" de- fined in Chapter 1, and concluded that none did. It offers some additional observations on research needs and recom- mendations for action: Indoor environments subject occupants to multiple exposures that may interact physically or chemically with one another and with the other characteristics of the environment, such as humidity, temperature, and ven- tilation rate. Few studies to date have considered whether there are additive or synergistic interactions among these factors. The committee encourages researchers to collect and analyze data on a broad range of exposures and factors characterizing indoor environments in order to inform these ques- tions and possibly point the way toward more effective and efficient inter- vention strategies. The committee encourages the CDC to pursue surveillance and addi- tional research on acute pulmonary hemorrhage or hemosiderosis in infants to resolve questions regarding this serious health outcome. Epidemiologic and case studies should take a broad-based approach to gathering and evaluating information on exposures and other factors that would help to elucidate the etiology of acute pulmonary hemorrhage or hemosiderosis in infants, including dampness and agents associated with damp indoor

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12 DAMP INDOOR SPACES AND HEALTH environments; environmental tobacco smoke (ETS) and other potentially adverse exposures; and social and cultural circumstances, race/ethnicity, housing conditions, and other determinants of study subjects' health. Concentrations of organic dust consistent with the development of organic dust toxic syndrome are very unlikely to be found in homes or public buildings. However, clinicians should consider the syndrome as a possible explanation of symptoms experienced by some occupants of highly contaminated indoor environments. Greater research attention to the possible role of damp indoor envi- ronments and the agents associated with them in less well understood disease entities is needed to address gaps in scientific knowledge and con- cerns among the public. Prevention and Remediation of Damp Indoor Environments Homes and other buildings should be designed, operated, and main- tained to prevent water intrusion and excessive moisture accumulation when possible. When water intrusion or moisture accumulation is discov- ered, the source should be identified and eliminated as soon as practicable to reduce the possibility of problematic microbial growth and building- material degradation. The most effective way to manage microbial con- taminants, such as mold, that are the result of damp indoor environments is to eliminate or limit the conditions that foster its establishment and growth. That also restricts the dampness-related degradation of building materials and furnishings. Information is available on the sources of excessive indoor dampness and on the remediation of damp indoor conditions and its adverse conse- quences. Chapter 6 summarizes several sources of guidance on how to respond to various indoor microbial contamination situations. However, as the committee observes, determining when a remediation effort is war- ranted or when it is successful is necessarily subjective because there are no generally accepted health-based standards for acceptable concentrations of fungal spores, hyphae, or metabolites in the air or on surfaces. There is a great deal of uncertainty and variability in samples of mold and other microbial materials taken from indoor air and surfaces, but the information gained from a careful and complete survey may aid in the evaluation of contamination sources and remediation needs. Visible sur- faces and easily accessible spaces are not the only source of microbial contaminants, however, and the potential for exposure from sources in spaces such as attics, crawl spaces, wall cavities, and other hidden or seldom- accessed areas is poorly understood. When microbial contamination is found, it should be eliminated by means that not only limit the possibility of recurrence but also limit expo-

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EXECUTIVE SUMMARY 13 sure of occupants and persons conducting the remediation. Disturbance of contaminated material during remediation activities can release microbial particles and result in contamination of clean areas and exposure of occu- pants and remediation workers. Containment during clean-up (through the erection of barriers, application of negative air pressure, and other means) has been shown to prevent the spread of microbial particles to noncon- taminated parts of a contaminated building. The amount of containment and worker personal protection and the determination of whether occupant evacuation is appropriate depend on the magnitude of contamination. Notwithstanding the interest in the topic, very few controlled studies have been conducted on the effectiveness of remediation actions in elimi- nating problematic microbial contamination in the short and long term or on the effect of remediation actions on the health of building occupants. In addition, the available literature addresses the management of microbial contamination when remediation is technically and economically feasible. There is no literature addressing situations where intervening in the moisture dynamic or cleaning or removing contaminated materials is not practicable. Among the research needs identified by the committee are studies that better characterize the effectiveness of remediation assessment and remedia- tion methods in different contamination circumstances, the dynamics of movements of contaminants from colonies of mold and other microorgan- isms in spaces such as attics, crawl spaces, exterior sheathing, and garages, and the effectiveness of various means of protection of workers and occu- pants during remediation activities. Standard methods should be formulated to assess the potential of new materials, designs, and construction practices to cause or exacerbate dampness problems. And research should be performed to address the other data gaps discussed above and to determine How free of microbial contamination a surface or building material must be to eliminate problematic exposure of occupants and in particular, how concentrations of microbial contamination left after remediation are related to those found on ordinary surfaces and materials in buildings where no problematic contamination is present. Whether and when microbial contamination that is not visible to the naked eye but is detectable through screening methods should be remediated. The best ways to open a wall or other building cavity to seek hidden contamination while controlling the release of spores, microbial fragments, and the like. The effectiveness of managing contamination in place by using nega- tive air pressure, encapsulation, and other means of isolation. How to measure the effectiveness and health effects of a remediation effort.

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14 DAMP INDOOR SPACES AND HEALTH The Public Health Response On the basis of its review of the scientific papers and other informa- tion summarized above and detailed in the report, the committee con- cludes that excessive indoor dampness is a public-health problem. An appropriate public health goal should thus be to prevent or reduce the incidence of potentially problematic damp indoor environments, that is, environments that may be associated with undesirable health effects, par- ticularly in vulnerable populations. However, there are serious challenges associated with achieving that goal. As the report indicates, there is insuf- ficient information on which to base quantitative recommendations for either the appropriate level of dampness reduction or the "safe" level of exposure to dampness-related agents. The relationship between dampness or particular dampness-related agents and health effects is sometimes unclear and in many cases indirect. Questions of exposure and dose have not, by and large, been resolved. It is also not possible to objectively rank dampness-related health problems within the larger context of threats to the public's health because there is insufficient information available to confidently quantify the overall magnitude of the risk resulting from ex- posures in damp indoor environments. Institutional and social barriers may hinder the widespread adoption of technical measures and practices that could prevent or reduce problematic indoor dampness. Economic factors, for example, encourage poor practice or impede remediations; they may also create incentives to forgo or limit investment in maintenance that might help to prevent moisture problems. Given these challenges, the committee identifies seven areas of endeavor that deserve discussion in the formulation of public health mechanisms to prevent or reduce the incidence of damp indoor environments: Assessment and monitoring of indoor environments at risk for prob- lematic dampness. Modification of regulations, building codes, and building-related contracts to promote healthy indoor environments; and enforcement of existing rules. Creation of incentives to construct and maintain healthy indoor environments; and financial assistance for remediation where needed. Development, dissemination, and implementation of guidelines for the prevention of dampness-related problems. Public-health-oriented research and demonstration projects to evalu- ate the short-term and long-term effectiveness of intervention strategies. Education and training of building occupants, health professionals, and people involved in the design, construction, management, and mainte-

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EXECUTIVE SUMMARY 15 nance of buildings to improve efforts to avoid or reduce dampness and dampness-related health risks. Collaborations among stakeholders to achieve healthier indoor environments. Among the recommendations the committee offers for implementing the actions it suggests are these: CDC, other public-health-related, and building-management- related funders should provide new or continuing support for research and demonstration projects that address the potential and relative benefit of various strategies for the prevention or reduction of damp indoor environments, including data acquisition through assessment and moni- toring, building code modification or enhanced enforcement, contract language changes, economic and other incentives, and education and train- ing. These projects should include assessments of the economic effects of preventing building dampness and repairing damp buildings and should evaluate the savings generated from reductions in morbidity and gains in the useful life of structures and their components associated with such interventions. Carefully designed and controlled longitudinal research should be undertaken to assess the effects of population-based housing interventions on dampness and to identify effective and efficient strategies. As part of such studies, attention should be paid to definitions of dampness and to measures of effect; and the extent to which interventions are associated with decreased occurrence of specific negative health conditions should be assessed when possible. Government agencies with housing-management responsibility should evaluate the benefit of adopting economic-incentive programs designed to reward actions that prevent or reduce building dampness. Ideally, these should be coupled with independent assessments of effectiveness. HUD or another appropriate government agency with responsibility for building issues should provide support for the development and dis- semination of consensus guidelines on building design, construction, opera- tion, and maintenance for prevention of dampness problems. Development of the guidelines should take place at the national level and should be under the aegis of either a government body or an independent nongovernment organization that is not affiliated with the stakeholders on the issue. CDC and other public-health-related funders should provide new or continuing support for research and demonstration projects that: -- Develop communication instruments to disseminate information derived from the scientific evidence base regarding indoor dampness, mold

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16 DAMP INDOOR SPACES AND HEALTH and other dampness-related exposures, and health outcomes to address public concerns about the risk from dampness-related exposures, indoor conditions, and causes of ill health. -- Foster education and training for clinicians and public- health professionals on the potential health implications of damp indoor environments. Government and private entities with building design, construction, and management interests should provide new or continuing support for research and demonstration projects that develop education and training for building professionals (architects, home builders, facility managers and maintenance staff, code officials, and insurers) on how and why dampness problems occur and how to prevent them. Those formulating the education and training programs discussed above should include means of evaluating whether their programs are reach- ing relevant persons and, ideally, whether they materially affect the occur- rence of moisture or microbial contamination in buildings or occupant health. REFERENCE U.S. Census Bureau. 2003. Statistical Abstract of the United States 2002. United States De- partment of Commerce.