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Mold and Endotoxin Levels in the Aftermath of Hurricane Katrina: A Pilot Project of Homes in New Orleans Undergoing Renovation

Mold and Endotoxin Levels in the Aftermath of Hurricane Katrina: A Pilot Project of Homes in New... Research Mold and Endotoxin Levels in the Aftermath of Hurricane Katrina: A Pilot Project of Homes in New Orleans Undergoing Renovation 1 2 3 4 3 5 Ginger L. Chew, Jonathan Wilson, Felicia A. Rabito, Faye Grimsley, Shahed Iqbal, Tiina Reponen, 6 7 8 2 Michael L. Muilenberg, Peter S. Thorne, Dorr G. Dearborn, and Rebecca L. Morley Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York, USA; 2 3 4 National Center for Healthy Housing, Columbia, Maryland, USA; Department of Epidemiology, and Department of Environmental Health, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana, USA; Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio, USA; Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA; Department of Occupational & Environmental Health, The University of Iowa, College of Public Health, Iowa City, Iowa, USA; Department of Environmental Health Sciences, Case Western Reserve University, Cleveland, Ohio, USA sustained between 0.3 and 1.8 m of flood BACKGROUND: After Hurricane Katrina, many New Orleans homes remained flooded for weeks, damage from Hurricanes Katrina and Rita. promoting heavy microbial growth. Three specific objectives of the demonstration were a) to make recommendations for safe OBJECTIVES: A small demonstration project was conducted November 2005–January 2006 aiming to recommend safe remediation techniques and safe levels of worker protection, and to characterize reentry into a home and safe removal of flood- airborne mold and endotoxin throughout cleanup. damaged furnishings and building materials, including levels of worker protection; b)to METHODS: Three houses with floodwater lines between 0.3 and 2 m underwent intervention, including disposal of damaged furnishings and drywall, cleaning surfaces, drying remaining struc- characterize the distribution of airborne mold ture, and treatment with a biostatic agent. We measured indoor and outdoor bioaerosols before, and endotoxin (a cell wall component of gram- during, and after intervention. Samples were analyzed for fungi [culture, spore analysis, polymerase negative bacteria) throughout all phases of the chain reaction (PCR)] and endotoxin. In one house, real-time particle counts were also assessed, cleanup; and c) to comment on the practicality and respirator-efficiency testing was performed to establish workplace protection factors (WPF). of the overall cleanup process. To this end, RESULTS: At baseline, culturable mold ranged from 22,000 to 515,000 colony-forming units/m , Enterprise Community Partners and the spore counts ranged from 82,000 to 630,000 spores/m , and endotoxin ranged from 17 to 139 NCHH, in collaboration with Neighborhood endotoxin units/m . Culture, spore analysis, and PCR indicated that Penicillium, Aspergillus, and Housing Services of New Orleans and several Paecilomyces predominated. After intervention, levels of mold and endotoxin were generally lower partners from academic institutions, studied (sometimes, orders of magnitude). The average WPF against fungal spores for elastomeric respira- these issues as part of the demonstration pro- tors was higher than for the N-95 respirators. ject, which was conducted between November CONCLUSIONS: During baseline and intervention, mold and endotoxin levels were similar to those 2005 and January 2006. found in agricultural environments. We strongly recommend that those entering, cleaning, and repairing flood-damaged homes wear respirators at least as protective as elastomeric respirators. Materials and Methods Recommendations based on this demonstration will benefit those involved in the current cleanup Selection of homes. Three single-family houses activities and will inform efforts to respond to future disasters. in the Gentilly district of New Orleans were KEY WORDS: endotoxin, flood, fungi, mold, Hurricane Katrina, New Orleans, remediation, selected to participate in the project. Most of respirators. Environ Health Perspect 114:1883–1889 (2006). doi:10.1289/ehp.9258 available via the areas in Gentilly lie 0.5–4 m below sea level http://dx.doi.org/ [Online 24 August 2006] [Greater New Orleans Community Data Center (GNOCDC) 2006a]. Eighty-five per- Hurricane Katrina, which occurred on affordably removed from the flooded homes cent of the total households in this area suffered 29 August 2005, caused the breach of several prior to building restoration. On 27 October some degree of damage, and 71% of households levees surrounding New Orleans, Louisiana, 2005, the National Center for Healthy and left over 75% of the city underwater. A Housing (NCHH) convened a meeting to Address correspondence to G.L. Chew, Mailman storm surge from Hurricane Rita several weeks examine options for flood cleanup procedures School of Public Health, Columbia University, 60 later reflooded many areas of the city. In the and air sampling. Attendees included building Haven Ave., B-1, New York, NY 10032-4206 USA. Telephone: (212) 305-1692. Fax: (212) 305-4012. aftermath of these disasters, homes were sub- materials scientists, mold remediation experts, E-mail: [email protected] merged in flood water for several summer members of community-based organizations, This work was funded by Enterprise Community weeks, resulting in severe mold and bacterial industrial hygienists, clinicians, housing pol- Partners with support from the Robert Wood growth, both of which can lead to a panoply of icy makers, and environmental epidemiolo- Johnson Foundation, NeighborWorks America, respiratory health effects [Institute of Medicine gists from across the country (including areas Swetland Center for Environmental Health, Case (IOM) 2004]. Although several studies have affected by Hurricane Katrina). The atten- Western Reserve University, the University of Iowa Environmental Health Sciences Research Center assessed markers of mold and bacteria in damp dees drew on a body of guidance documents [National Institutes of Health (NIH) grant P30 and water-damaged homes (IOM 2004), there for flood cleanup and mold remediation ES05605], National Institute for Occupational Safety is a dearth of literature documenting the levels [American Red Cross and Federal Emergency and Health NORA Research Program of the of these agents in homes that received sus- Management Agency 1992; Centers for University of Cincinnati Education and Research tained flooding (Ross et al. 2000). Disease Control and Prevention (CDC) 2005; Center Grant (T42/CCT510420), and Columbia New Orleans and the surrounding com- Louisiana State University 2005; New York University’s National Institute of Environmental Health Sciences Center for Environmental Health in munities currently face difficult decisions City Department of Health and Mental Northern Manhattan (P30 ES009089). G.L.C. is an regarding whether or not to demolish large Hygiene 2002; U.S. Environmental Protection NIH National Center on Minority Health and numbers of damaged homes. Many factors Agency (EPA) 2001). Health Disparities fellow. will be taken into consideration when those The overall purpose of this demonstration The authors declare they have no competing decisions are made, including the question of was to assess the efficacy of flood cleanup pro- financial interests. whether mold and bacteria can be safely and cedures in three houses in New Orleans, which Received 11 April 2006; accepted 24 August 2006. Environmental Health Perspectives • VOLUME 114 | NUMBER 12 | December 2006 1883 Chew et al. were severely damaged or destroyed by flooding meter with a probe (J-LITE Moisture Meter, using sponge mops and hand sponges to wash from Hurricane Katrina (GNOCDC 2006b). Delmhorst Instrument Company, Towaco, down surfaces with a non-trisodium phosphate To be included in the demonstration, a NJ); moisture readings > 22% were considered solution of sodium sesquicarbonate detergent house had to be flooded with < 2 m of water, saturated, and those < 15% were considered and 15% dilution of household chlorine structurally sound, and located in an area likely dry (U.S. Department of Agriculture 1999). bleach. In all three houses, dry cleaning was to be rebuilt. Owners were required to have The supervisors determined whether electrical conducted before wet cleaning. In house 2, all flood insurance deemed adequate to rebuild service, if operable, was safe and verified that surfaces including all framing members were their house and intentions to rebuild. The first there were no water or gas leaks. wet cleaned. In houses 1 and 3, workers wet house was selected when an employee of a In house 1, surfaces were relatively dry at cleaned only hard, nonporous surfaces (e.g., New Orleans–based nonprofit housing orga- the time of the demonstration, with no stand- tubs, sinks, toilets, tile flooring). nization volunteered his house for the pro- ing water. Possessions with visual mold and Biostat treatments. After cleaning, the three ject. Neighborhood Housing Services, a limited value to the owner of house 1 were houses received biostat treatment with one of chartered member of NeighborWorks discarded. Other hard surface possessions were two borate formulations to prevent future America (Washington, DC), identified two cleaned outside with a bleach–detergent solu- emergence of mold. House 1 was treated with additional homeowners whose houses met the tion and then packed in boxes and moved to Bora-Care (Nisus Corp., Rockford, TN); inclusion criteria. the second floor of the house. House 2 had house 2 was treated with Bora-Care in half the At house 1, the homeowner selected the been closed since Hurricane Katrina and was house and Termite Prufe (Copper Brite, Inc., contractor to complete the work. At houses 2 still relatively wet at the start of the project, Santa Barbara, CA) in the other half; and and 3, Neighborhood Housing Services of with standing water, wet furnishings, and plas- house 3 was treated with Termite Prufe. The New Orleans selected the contractors and ter and drywall surfaces saturated with water. active ingredient in both Bora-Care and supervised the activities, with support from the In house 3, personal belongings, furniture, Termite Prufe is disodium octoborate tetra- NCHH and Urban Renovation Consultants. and lower cabinets had been removed by the hydrate. Both products are fungicides registered Urban Renovation Consultants and the time of the initial inspection. The carpet and by the U.S. EPA. Bora-Care was mixed with NCHH, as well as its national advisory work padding were wet, and the drywall was satu- water (1:3 or 1:4) and sprayed onto all lumber group, developed the construction specifica- rated within 0.3 m of the floor. Details of the sheathing to the point of wetness in confor- tions used at the three houses. baseline conditions and demonstration activi- mance with the manufacturer’s instructions. Personal protective equipment. All workers ties are listed in Table 1. Termite-Prufe (0.45 kg powder to 3.8 L water) and supervisors wore N100 filtering facepiece Deconstruction. Deconstruction at all was applied to all exposed interior surfaces at respirators, nonwoven polypropylene dispos- houses included removing carpet or otherwise 18.7 m per 3.8 L, working from ceiling to able coveralls, and gloves during the property clearing floors down to the finished flooring and floor. The two formulations differ significantly inspection. During property removal and removing insulation, nails on studs, and lower in cost after mixing (Bora-Care was 2.5 times deconstruction, some workers also used half- cabinets, if present. At house 1, bathroom toi- more expensive than Termite Prufe). face HEPA (high-efficiency particulate air) fil- lets, sinks, and bathtubs were also removed. At Drying. Windows in houses 2 and 3 were ter air-purifying respirators (some equipped house 2, workers also removed upper cabinets. left open to allow cross-ventilation to dry the with organic solvent filters) and goggles. Cleaning and sanitizing. Workers cleaned moisture introduced by the biostat treat- Baseline inspection. The supervisors visu- and sanitized all three houses with a combina- ments. All possessions had been removed ally inspected each house for roof leakage, tion of dry-cleaning and wet-cleaning steps. from these houses, so security was not a con- standing water, and the extent of mold on Workers conducted dry cleaning by bristle cern. In house 1, some possessions were walls, cabinets, floors, doors, trim, appliances, brushing studs and other framing members to stored on the second floor, thus windows equipment, and heating ventilation/air condi- remove visible mold growth and then vacuum- were closed, but the upstairs ceiling fan was tioning ductwork. The moisture content of ing the same surfaces with a HEPA filter used. No mechanical dehumidification was the wood studs was tested using a moisture attachment. Wet cleaning was completed by used in any of the houses. Table 1. Baseline conditions and demonstration activities in houses. Baseline description Removal of flood-damaged items Cleaning Drying Biostatic agent used House 1 Built in 1987 Owner moved some cleaned Durable furnishings were wet- Owner left an upstairs Bora-Care (1:3 dilution) Two-story, slab on grade with personal belongings (clothes, cleaned, wiped dry, and placed ceiling fan on throughout attached apartment on the items in cardboard boxes) to the in storage inside the home the duration of the first floor second floor of the home for Only concrete and vinyl floors and demonstration project, but Water line at 0.3 m above floor storage countertops were wet-cleaned windows were closed Roof had been patched with a Bottom 1.2 m of drywall was Ceiling was not dry-cleaned temporary tarp before removed initiating flood cleanup Electricity operational House 2 Approximately 100 years old Furnishings and appliances were All surfaces were wet- and dry- Windows left open for Bora-Care (1:4 dilution) in One-story raised home with too damaged to salvage, so cleaned 2 weeks before applying a front half of home plywood underlayment on workers removed all furnishings biostat treatment 0.6-m piers for disposal Windows left open after Termite Prufe in back half Water line at 1.8 m above floor Drywall was removed floor to application of biostatic of home Electricity not operational ceiling agent House 3 Built in 2004 Owners had removed all personal All surfaces were dry-cleaned Windows left open after Termite Prufe One-story raised home with belongings, furniture, appliances, Only toilets, sinks, bathtubs, and application of biostatic plywood underlayment on and lower kitchen cabinets prior vinyl floors were wet-cleaned agent 0.9-m piers to the demonstration Water line at 0.6 m above floor Drywall was removed floor to Electricity not operational ceiling 1884 VOLUME 114 | NUMBER 12 | December 2006 • Environmental Health Perspectives Mold and endotoxin in New Orleans houses Air sampling. We conducted air sampling instrument measured the number of particles Samples were vortexed, and 100-µL aliquots during three time points for each home: in 15 size ranges, from 0.3 to 20.0 µm. We (undiluted, 1:10, and 1:100 dilution) were a) before intervention (i.e., day 1), b) during used an averaging time of 1 min. spread-plated onto two types of culture media: intervention (i.e., day 1 or 2), and c) after inter- We performed respirator-efficiency testing dichloran glycerol and malt extract agar. vention (i.e., day 36, 23, and 15, respectively, by measuring workplace protection factor Culture plates were incubated at two different for houses 1, 2, and 3). The preintervention (WPF) against fungal spores collected in temperatures: 25°C for 7–10 days or 37°C for sampling for house 1 occurred 1 day after some house 3. The institutional review board of The 2–3 days. For each type of media and each items were removed from the house, but before University of Cincinnati approved this sam- temperature, the plates with nearest 10–30 work commenced on the second day. For pling protocol, and informed written consent colonies were counted. Culturable fungi were houses 2 and 3, the preintervention sampling was obtained by the university investigator reported in colony-forming units (CFU). occurred either 1 day or a few hours before who wore the respirators. We tested two types Fungal spore counts. We analyzed fungal demonstration commenced. Intervention sam- of respirators: a disposable N-95 filtering face- spores by direct microscopic examination of pling occurred within a few hours of removal of piece respirator (model 8110; 3M, St. Paul, 27% of the impaction surface using transverse mold-laden drywall. Postintervention sampling MN) and an elastomeric half-facepiece respira- scans across the spore deposit at 400× magni- occurred between 1 and 2 weeks after borate tor (North 5500-30 with North filter cartridge fication. Larger, infrequently recovered spore solution was applied. Table 2 summarizes the gas and vapor with P100 particulate filter; types were counted by scanning the full air sampling activities conducted in each home. North Safety Products, Cranston, RI). The impaction surface at 200× magnification. In Indoor samples. Using battery-operated experimental protocols and the N-95 filtering situations with very high spore concentra- air sampling pumps (AirChek 2000; SKC, facepiece respirator were as described in an tions, where resulting spore densities were Inc., Eighty Four, PA), we sampled the living agriculture study by Lee et al. (2005). In brief, extreme, fewer transverse scans were per- room air for 20 min at a flow rate of the subject was fit-tested before the experi- formed using a 120-µm reticule (for example, 2.5 L/min with 2.0-µm pore Teflon filters ment using the Portacount method (TSI, Inc., 0.017% of the deposit was scanned in one (Omega Specialty, Inc., Chelmsford, MA) St. Paul, MN). The subject wore the test res- sample). Most spores were identified by housed in 37-mm cassettes. In some houses, pirator, which was connected to a newly devel- genus; Aspergillus, Penicillium, Eurotium, and additional samples were collected upstairs oped personal sampling setup, for 30 min. In Paecilomyces are difficult to discern by this (house 1) and in the bedroom (house 3). The the sampling setup, fungal spores were col- method and were grouped into one category. pumps were attached to a tripod 1.2–1.35 m lected from inside and outside the respirator Polymerase chain reaction (PCR). Aliquots above the floor, with the sampling cassette onto polycarbonate filters. Concentration of of the Teflon filter extracts were analyzed by P open to the center of the room. Using fungal spores (spores per cubic meter) was & K Microbiological Services, Inc. (Cherry high-flow (15 L/min) air sampling pumps determined through microscopic counting of Hill, NJ) for species-specific quantification (Environmental Monitoring Systems, Inc., the filters (Adhikari et al. 2003; Lee S-A et al. using quantitative PCR (qPCR) following the Charleston, SC), fungal spores were collected 2006). WPF was calculated by dividing the methods previously described by Haugland in the living room air using BioCell impaction fungal spore concentration inside the respira- et al. (2004) and Vesper et al. (2004). cassettes (GrafTech, Inc., Brighton, MI) for tor by that outside the respirator near the sub- Reference controls were used as positive quanti- 2 min pre- and postintervention, and 1 min ject’s breathing zone. The test was repeated tative controls. Independent qPCR analyses during intervention. Lack of electricity pre- twice with the N-95 respirator and four times were performed using primers and probes vali- cluded postintervention indoor and outdoor with the elastomeric respirator. dated specifically for the 23 species/species sampling with the high-flow pumps for houses Outdoor samples. To collect outdoor sam- groups of interest: Acremonium strictum, 2 and 3. Sampling trains were pre- and post- ples, we placed the battery-operated AirChek Alternaria alternata, Aspergillus flavus/oryzae, calibrated, and the average flow rate was used 2000 pumps 3 m outside the front door for Aspergillus fumigatus, Aspergillus niger, in calculations of volume of air sampled. collection of one preintervention sample for Aspergillus ochraceus, Aspergillus sydowii, Particle counts were measured in real-time house 3, one sample during the intervention Aspergillus ustus, Aspergillus versicolor, Eurotium for house 3 (before and during intervention) for house 2, and postintervention samples for (Aspergillus) amstelodami, Chaetomium globo- using an optical particle counter (model 1.108; all three homes. We also collected samples sum, Cladosporium cladosporioides, Memnoniella Grimm Technologies, Douglasville, GA). This before and during intervention using the high- echinata, Paecilomyces variotii, Penicillium flow pumps placed at 3 and 10 m outside the aurantiogriseum, Penicillium brevicompactum, Table 2. Air sampling activities conducted for front door. Also, some outdoor samples were Penicillium chrysogenum, Penicillium purpuro- houses (indicated by X). not collected during inclement weather genum, Penicillium variabile, Scopulariopsis Activity House 1 House 2 House 3 because of concerns regarding technician safety brevicaulis/fusca, Stachybotrys chartarum, Indoor air (culturable fungi, endotoxin, PCR) and equipment damage. Trichoderma viride/koningii, and Ulocladium Prework X X X Field blanks. On sampling days when botrytis. During work X X X intervention occurred, we collected a blank Endotoxin. Aliquots of the Teflon filter Postwork X X X BioCell to assess fungal spores that could have extracts were analyzed for endotoxin by the Indoor air (fungal spores) been on the collection media before sampling, kinetic chromogenic Limulus amebocyte lysate Prework X X X that were introduced in the moments before assay (Thorne 2000; Vojta et al. 2002). Levels During work X X X Postwork X starting and after stopping the pump, and dur- of endotoxin were reported in endotoxin Outdoor air (culturable fungi, endotoxin, PCR) ing sample transport. The BioCell cassette was units (EU). Prework X opened for 1 min in the house (without attach- During work X Results ment to a sampling pump), and then sealed. Postwork X X X All blanks were negative for fungal spores. Comparison of levels before, during, and after Outdoor air (fungal spores) Analytical methods. Culture of fungi. intervention. The baseline levels of mold and Prework X X X During work X X X Teflon filters were placed in 5 mL pyrogen- endotoxin, some of which varied by orders of Postwork X free water with 0.05% Tween 20 in sterile magnitude within homes, are shown in Respirator-efficiency testing X plastic tubes and shaken for 1 hr at 25°C. Table 3. The preintervention samples for Environmental Health Perspectives • VOLUME 114 | NUMBER 12 | December 2006 1885 Chew et al. house 1 were taken after some belongings had the Basidiomycota. Culture at 25°C and spore component of gram-negative bacteria, we been removed the previous day, yet the baseline counting showed that Trichoderma was com- speculate that the bacteria were killed but that levels were still generally below those of the monly recovered in the indoor air samples. A endotoxin remained in the settled dust after other two houses. What is clear from Figure 1 is PCR probe for Trichoderma virde/koningii had the intervention. Nonetheless, the levels of that postintervention levels of all bioaerosols in a low recovery, suggesting that other methods mold (as determined by three different each house tended to be lower than at pre- may have been detecting another common methodologies) were drastically reduced after intervention, except endotoxin in house 2, Trichoderma species such as Trichoderma the intervention in house 2. which was moderately elevated, and culturable harzianum. A strength of our study was the multi- mold in house 1, which had postintervention Particle counts. Figure 4 presents results pronged assessment of mold exposure. From levels similar to those collected preintervention. of total particle counts, and Figure 5 shows our data, it is clear that the use of any one of Because generators were not available at all sam- size-selective particle concentrations. For the the analytical methodologies (culture, pling periods at houses 2 and 3, several mold data analysis, we combined the 15 channels of microscopy, or PCR) would have shown that spore count measurements could not be col- the optical particle counter into four size baseline levels of mold were high compared lected. However, house 1 had spore measure- ranges: 0.3–0.8, > 0.8–3.0, > 3.0–7.5, and with agricultural, industrial, or other home ments from all three time points, and the > 7.5–20.0 µm. Results show that number environments. However, each analytical pattern was similar to that of the culturable concentrations of particles of all sizes method gave different insight that we hope fungi, PCR, and endotoxin results; levels increased during intervention, most clearly for will inform future investigations in homes in increased during work and then decreased after particles > 0.8 µm. In contrast, during the New Orleans and in other environments. In intervention (Figure 2). lunch break, the concentration of particles contrast to culture methods to detect and enu- Differences and similarities in fungal taxa > 0.8 µm decreased almost to the same level merate fungi, spore microscopy and qPCR do profiles. Interpretations of the predominant as measured before the intervention. not require viable fungal elements. In addi- fungi recovered in the air samples differ Efficiency of respiratory protection. The tion, spore microscopy and qPCR detect not depending upon the type of analysis. As WPF values for the two types of tested respira- only dead fungi but those that compete poorly shown in Figure 3, Aspergillus, Paecilomyces, tors are presented in Table 4. The average on the various media used to grow fungi. The and Penicillium were among the most fre- WPF against fungal spores for the elastomeric culture-based analyses (on both malt extract quently detected fungal taxa determined by all respirator was higher than that measured for agar and DG18 agars) can underestimate the three methodologies (culture, PCR, and spore the N-95 filtering facepiece respirator. populations of some Aspergillus species by counting). Most of the spore count was due to orders of magnitude when compared with Discussion Aspergillus/Pencillium spores. In house 1, qPCR (Meklin et al. 2004). In contrast, Stachybotrys was recovered in the living room A critical finding of the present study is that in Basidiomycota spores (the common mushroom and in outdoor air during the intervention, homes that held flood waters for several weeks, is in this fungal phylum) generally do not grow but decreased to nondetectable levels by the our flood cleanup techniques were associated well on culture plates, and a probe was not postintervention sampling visit. Cladosporium with a reduction in mold and endotoxin lev- available for PCR analysis; therefore, only spore was not frequently recovered from culture; els. In all three homes, the interventions microscopy enabled detection of this potentially however, it was frequently detected by PCR decreased mold levels and in some cases, the allergenic group of molds (Horner et al. 1995; and spore counts, but at low concentrations decreases were several orders of magnitude. In Lehrer et al. 1986). The low frequency of relative to Aspergillus and Penicillium. In fact, the only measure that increased from pre- Trichoderma and Alternaria detection by PCR addition, spores of Curvularia and the intervention to postintervention was endo- compared with the moderate to high frequency Basidiomycota (including rusts, smuts, and toxin in house 2. This house had the most of recovery by direct microscopy and, to a lesser basidiospores) were identified by microscopy. extensive flood damage, and during the inter- extent, culture likely reflects the airborne pres- Neither PCR nor culture methods used in this vention, endotoxin was higher than in the ence of taxa (e.g., T. harzianum and Alternaria analysis had the ability to measure spores of other houses. Because endotoxin is a cell wall tenuissima) for which PCR probes were not used or available. The spore microscopy also Table 3. Baseline indoor concentrations of mold and endotoxin. revealed that Curvularia was common in the houses. Although a PCR probe for Curvularia Total culturable mold Total mold spore PCR results 3 a 3 3 3 was not available for analysis of these samples, (CFU/m ) counts (spores/m ) (spore equivalents/m ) Endotoxin (EU/m ) culture analysis should have been able to grow House 1 22,000–46,000 82,381 80,779 43 Curvularia. The low prevalence of culturable House 2 268,000–515,000 202,634 1,039,841 17 House 3 BR = 29,000–59,000 634,651 BR = 77,911 BR = 100 Cladosporium contrasts with the high preva- LR/Kit = 332,000–342,000 LR/Kit = 178,067 LR/Kit = 139 lence, as determined by microscopy and PCR. Cladosporium is one of the most common fun- Abbreviations: BR, bedroom; Kit, Kitchen; LR, living room. The average of samples grown on two different media and incubated at two different temperatures, resulting in four gal taxa recovered indoors and outdoors plates per sample collected. House 1 7 4 10 10 House 2 8 6 10 10 A B C House 3 5 10 Outdoor 6 10 2 0 0 0 10 10 10 Prework Work Postwork Prework Work Postwork Prework Work Postwork Sampling period Sampling period Sampling period Figure 1. Results of filter samples from the three houses using three different analytical methods: total culturable mold (A; results are shown only for those grown on malt extract agar and cultured at 25°C), PCR (B), and endotoxin (C). Work for house 1 is the average of two measurements (upstairs and downstairs); outdoor prework is represented only by house 3; outdoor work is represented only by house 2; and outdoor postwork represents the average of the three houses. 1886 VOLUME 114 | NUMBER 12 | December 2006 • Environmental Health Perspectives Culturable mold (CFU/m ) PCR (spore equivalents/m ) Endotoxin (EU/m ) Mold and endotoxin in New Orleans houses throughout the world (Chew et al. 2001, mold, and endotoxin, suggest that a substan- of 1970). Still, no defined level of mold is 2003; IOM 2004; Levetin 1995; Su et al. tial portion of the particle counts could be listed that warrants a specific level of respira- 2001). Cladosporium competes well with composed of fungal and bacterial material tory protection. An assigned protection fac- many of the other taxa that we recovered, so even during periods of inactivity. tor, which can be used in the initial selection the reason for its decreased culturability in our The choice of respirator depends on the of respirator type, gives the level of the respi- samples remains elusive. expected level of contamination. Currently, ratory protection that a properly functioning At baseline and particularly during inter- there are no threshold limit values for mold respirator or class of respirators would be vention, we observed household levels of mold or endotoxin in the United States; however, a expected to provide to properly fitted and and endotoxin that equaled or surpassed those Dutch occupational health standard for trained users in the workplace (OSHA 2006). in wastewater treatment plants, cotton mills, endotoxin (50 EU/m ) existed for a brief The assigned protection factor for both filter- and agricultural environments (Christiani et al. time (Douwes et al. 2003). Also, excessive ing facepiece and elastomeric half-facepiece 1993; Lee J et al. 2006; Lee S-A et al. 2006; mold can be cited as a health concern by the respirators is 10 (e.g., 5,000,000 particles/m Spaan et al. 2006). Interestingly, the outdoor Occupational Safety and Health Adminis- would be reduced to 500,000 particles/m ) measurements were also higher than expected, tration (OSHA) under their General Duty (OSHA 2006). We found that, in the field, ranging from 10 to 25 EU/m . These exceed Clause (Occupational Safety and Health Act the WPF was lower for the N-95 respirator. the average outdoor endotoxin measurements from 13 Southern California communities of Culture (25°) 0.44 EU/m (Mueller-Anneling et al. 2004). Culture (37°) In addition, the baseline levels of culturable Spores mold in the three houses averaged 352,701 PCR CFU/m , which was much higher than the average (2,190 CFU/m ) or maximum level (48,760 CFU/m ) in homes sampled after the 1993 Mississippi River flood (Ross et al. 2000). The comparison with the Mississippi River flood study may somewhat overstate the disparity between the two floods because sam- pling in the earlier study occurred 1 year after the flood and only 40% of the residents in that study reported flood damage in their homes. Nonetheless, the levels of mold in the homes in the present study were extremely high. Given the level of visible mold observed when we first entered our demonstration homes, we were 0 concerned about the level of respiratory protec- tion required for entry and cleanup, and our Fungal taxa measurements of both the mold levels and the respirator WPFs supported our concern. Figure 3. Frequency of fungal taxa in samples of indoor and outdoor air from the three houses and during By the time we planned the initial visit to different timepoints grouped together. The sample size limited interpretation when stratifying by location house 3, we were able to characterize the par- and timepoints. Culture at 25°C (n = 35); culture at 37°C (n = 35); spore counting (n = 17); and PCR (n = 21). ticle sizes and conduct experiments to test the WPF of a disposable N-95 respirator and an elastomeric half-facepiece respirator. Our data indicate that counts of larger particles During renovation (10 January 2006) decreased drastically during the lunch break, taking almost 30 min to reach the lowest point, and reached counts of 50, 500, and 5,000/L of air (i.e., 50,000, 500,000, and 5,000,000 particles/m ) depending on the Lunch break size range. These data, combined with the measurements of mold spores, culturable 8 House 1 House 2 House 3 6 Outdoor Before renovation (9 January 2006) Prework Work Postwork Sampling period Figure 2. Results of mold spore counts. Only house 1 had an inside postwork measurement. Outdoor pre- work and work levels represent the average of the measurements for the three houses. Spore counts Time for house 1 decreased 77.6% between prework and postwork periods. Figure 4. Total particle concentrations before and during the renovation. Environmental Health Perspectives • VOLUME 114 | NUMBER 12 | December 2006 1887 Cladosporium Aspergillus Penicillium Paecilomyces Chaetomium Stachybotrys Trichoderma Alternaria Basidiomycetes Curvularia Zygomycetes Mold spores/m Percentage of samples with at least one colony Number concentration (no./L) 1436 Chew et al. In a previous study (Lee et al. 2005) in which of WPF data points in the present study is maximum particle penetration of approxi- the WPF against fungal spores was measured low, the results suggest that the elastomeric mately 0.03–0.07 µm (Balazy et al. 2006). in agricultural environments, the geometric half-facepiece respirators offer at least The postintervention findings in house 1 mean and geometric standard deviation of 21 10 times the protection against fungal spores. highlight the critical importance of fully clean- WPF data points was 25 and 9.9, respectively. Because the fungal spore concentrations were ing and drying a house. The upper walls and In addition, the WPF decreased with decreas- extremely high during the renovation, we ceilings in the house were not vacuumed as ing spore size. The values obtained from the question whether the protection offered by the part of the initial cleanup procedures. In addi- N-95 respirator in house 3 were somewhat N-95 filtering facepiece or the elastomeric res- tion, a small water leak saturated a portion of lower than those in agricultural environ- pirators is sufficient. Furthermore, our WPF the concrete floor after work was completed. ments. This could be due the composition of values are based on microscopic counting of Because possessions remained inside, the fungal load in the moldy building where intact spores. Recent studies have shown that house was closed and the humidity levels small Aspergillus/Penicillium spores predomi- exposure to fungi occurs also through sub- could have created a climate hospitable for nated. On the other hand, the WPF for the micrometer fungal fragments (Foto et al. further mold growth. The fact that culturable elastomeric respirator was clearly higher than 2005; Gorny et al. 2002; Green et al. 2005). mold levels in this home were not substan- the values obtained for the N-95 respirator in These particles may penetrate at even higher tially lower after intervention than before is this study and in the previous agricultural rates as intact spores because the filter materi- likely related to these factors. After post- study (Lee et al. 2005). Although the number als commonly used in N-95 respirators have intervention sampling was completed, the water leak in house 1 was fixed and cleaning and mechanical drying was conducted. 0.3–0.8 μm > 0.8–3.0 μm > 3.0–7.5 μm > 7.5–20.0 μm House 1 also offers a cautionary note about the risks involved with leaving some of Before renovation the original drywall in a home. Some flood cleanup guidance suggests that, in homes with 10 minimal flooding, removing drywall on walls to 1.2 m (4 ft is the width of a standard sheet of drywall) instead of to the ceiling can save 4 thousands of dollars in restoration costs (American Red Cross and Federal Emergency Management Agency 1992). However, many homes were submerged for weeks after Hurricane Katrina; although the water may have only wicked from the water line to the first 1.2 m, the homes were usually closed and the summer heat resulted in humidity levels similar to that of a terrarium. In our study, the house with the lowest water line (house 1) had visible mold growth in the wall cavities above 1.2 m after treatment. Although we cannot be certain that the growth would have occurred had cleaning and drying been ade- quate, the potential health risks of leaving the original drywall in the home must be taken During renovation into consideration. The question of whether household bleach is an effective treatment mechanism was one of the most debated topics among the advisory Lunch break group. Although it can have adverse environ- mental health effects, we used a dilute solution of bleach because of widespread concern of bacterial contamination and evidence that it could denature allergens (Chen and Eggleston 2001; Matsui et al. 2003) and possibly inacti- vate mycotoxins (Wilson et al. 2004). Bleach was selected primarily on the basis of federal Table 4. WPF against fungal spores with two types of respirators. WPF Respirator type No. of WPFs GM (GSD) N-95 filtering facepiece 2 5 (3.6) Elastometric half-facepiece 4 40 (2.9) Abbreviations: GM, geometric mean; GSD, geometric Time standard deviation. Each respirator type was tested in one subject. Figure 5. Size-selective particle concentrations before (A) and during (B) the renovation. 1888 VOLUME 114 | NUMBER 12 | December 2006 • Environmental Health Perspectives Concentration (no./L) Concentration (no./L) 1436 Mold and endotoxin in New Orleans houses guidance (American Red Cross and Federal reduced bioaerosols in the demonstration Hung LL, Miller JD, Dillon HK, eds. 2005. Field Guide for the Determination of Biological Contaminants in Environmen- Emergency Management Agency 1992; CDC houses, myriad issues including the qualifica- tal Samples. Fairfax, VA:American Industrial Hygiene 2005) and because it was widely accessible. In tions of those performing the work (including Association. house 2, bleach was applied to the wooden homeowners), depth and duration of flooding, IOM (Institute of Medicine). 2004. Damp Indoor Spaces and Health. Washington, DC:National Academies Press. building members, whereas it was not used in and the availability of electricity and supplies Lee J, Johnson JC, Reynolds SJ, Thorne PS, O’Shaughnessy house 3. Because the postintervention findings can affect the feasibility and ultimately the PT. 2006. Indoor and outdoor air quality assessment of for mold were similar in the two homes, we success of flood cleanup efforts. Our pilot pro- four wastewater treatment plants. J Occup Environ Hyg 3:36–43. are encouraged that intensive dry cleaning fol- ject was not designed for determining whether Lee S-A, Adhikari A, Grinshpun SA, McKay R, Shukla R, Li H, lowed by the application of borates appears to the demonstration homes were safe for reoccu- et al. 2005. Respiratory protection provided by N95 respira- control mold growth. The use of dry cleaning pancy. Rather, we examined the extent to tors against dust and microorganisms in agricultural farms. J Occup Environ Hyg 2:577–585. without wet cleaning the wood had the added which homes that experienced significant and Lee S-A, Adhikari A, Grinshpun SA, McKay R, Shukla R, Reponen benefit of reducing the time of flood cleanup prolonged exposure to flood waters could be T. 2006. Personal exposure to airborne dust and micro- because the workers did not need to allow the satisfactorily cleaned to enable reconstruction. organisms in agricultural environments. J Occup Environ wood to dry before applying borates. Research Future research may include revisiting these Health 3:118–130. Lehrer SB, Lopez M, Butcher BT, Olson J, Reed M, Salvaggio JE. to examine alternatives to bleach is under way. homes after reconstruction to determine 1986. Basidiomycete mycelia and spore-allergen extracts: If effective alternatives are identified, we whether the low bioaerosol levels persisted or skin test reactivity in adults with symptoms of respiratory would encourage their use to be incorporated even continued to decline. allergy. J Allergy Clin Immunol 78:478–485. Levetin E. 1995. Fungi. In: Bioaerosols (Burge HA, ed). Boca into the federal emergency response protocols. Raton, FL:Lewis Publishers, 87–120. Ideally the products should be accessible to REFERENCES Louisiana State University. 2005. Cleaning Flood Damaged consumers (both available and inexpensive) to Homes. Publication 2267. Baton Rouge, LA:Louisiana State Adhikari A, Martuzevicius D, Reponen T, Grinshpun SA, Cho S-H, University AgCenter. enable their adoption. Sivasubramani SK, et al. 2003. Performance of the button Matsui E, Kagey-Sobotka A, Chichester K, Eggleston PA. 2003. There are several noteworthy limitations personal inhalable sampler for the measurement of outdoor Allergic potency of recombinant Fel d 1 is reduced by low to the present study, including a) the small aeroallergens. Atmos Environ 34:4723–4733. concentrations of chlorine bleach. J Allergy Clin Immunol American Red Cross and Federal Emergency Management 111:396–401. sample size; b) inconsistency of the number of Agency. 1992. Repairing Your Flooded Home. ARC 4476, Meklin T, Haugland RA, Reponen T, Varma M, Lummus Z, samples collected; and c) possible lack of gen- FEMA L-198. Jessup, MD:American Red Cross and Federal Bernstein D, et al. 2004. Quantitative PCR analysis of house eralizability to other homes because of the Emergency Management Agency. Available: http://www. dust can reveal abnormal mold conditions. J Environ Monit redcross.org/static/file_cont333_lang0_150.pdf [accessed 6:615–620. home-selection process (Hung et al. 2005). 16 October 2006]. Mueller-Anneling L, Avol E, Peters JM, Thorne PS. 2004. Ambient The number of homes was necessarily small so Balazy A, Toivola M, Reponen T, Podgorski A, Zimmer A, endotoxin concentrations in PM from Southern California. that we could quickly try different types of Grinshpun SA. 2006. Manikin-based performance evalua- Environ Health Perspect 112:583–588. tion of N95 filtering-facepiece respirators challenged with cleanup procedures and assess their feasibility Nossiter A. 2006. The power is often off, but the rates may go nanoparticles. Ann Occup Hyg 50:259–269. up. The New York Times (New York, NY) 22 July: A14. and efficacy. To conduct the interventions in a CDC. 2005. Mold: Prevention Strategies and Possible Health New York City Department of Health and Mental Hygiene. 2002. larger set of homes would have prevented Effects in the Aftermath of Hurricanes Katrina and Rita. Guidelines on Assessment and Remediation of Fungi in Atlanta, GA:Centers for Disease Control and Prevention. expeditious reporting of findings. We had an Indoor Environments. New York:New York City Department Chen P, Eggleston PA. 2001. Allergenic proteins are fragmented of Health and Mental Hygiene. inconsistent number of samples because of the in low concentrations of sodium hypochlorite. Clin Exp Occupational Safety and Health Act of 1970. 1970. Public Law lack of electricity; as of 22 July 2006, this was Allergy 31:1086–1093. 91-596. Available: http://www.osha.gov/pls/oshaweb/ still a problem for much of New Orleans Chew G, Doekes G, Douwes J, Spithoven J, Brunekreef B. 2001. owadisp.show_document?p_table=OSHACT&p_id=2743 Fungal extracellular polysaccharides and B(1-3) glucans in [accessed 24 October 2006]. (Nossiter 2006), as was the lack of access to a house dust: relationship with culturable fungi. Indoor Air OSHA (Occupational Safety and Health Administration). 2006. fully functioning laboratory in New Orleans. 11:171–178. 29 CFR Parts 1910, 1915, and 1926: Assigned Protection We selected houses with a range of flood dam- Chew GL, Rogers C, Burge HA, Muilenberg ML, Gold DR. 2003. Factors; Final Rule. Fed Reg 71:50121–50192. Dustborne and airborne fungal propagules represent a dif- Ross MA, Curtis L, Scheff PA, Hryhorczuk DO, Ramakrishnan V, age; however, the houses were typical New ferent spectrum of fungi with differing relations to home Wadden RA, et al. 2000. Association of asthma symptoms Orleans building structures, and the level of characteristics. Allergy 58:13–20. and severity with indoor bioaerosols. Allergy 55:705–711. flooding was typical of many homes in the Christiani DC, Velazquez A, Wilcox M, Olenchock SA. 1993. Spaan S, Wouters IM, Oosting I, Doekes G, Heederik D. 2006. 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Vesper SJ, Varma M, Wymer LJ, Dearborn DG, Sobolewski J, removed ≥ 1.2 m of drywall, conducted Gulf Coast Housing Damage Estimates. Available: http://www. Haugland RA. 2004. Quantitative polymerase chain reaction HEPA vacuuming, used a borate salt solution gnocdc.org/reports/GulfCoast_HousingDamageEstimates_ analysis of fungi in dust from homes of infants who devel- 021206.pdf [accessed 11 April 2006]. oped idiopathic pulmonary hemorrhaging. J Occup Environ to help prevent mold growth, and used bleach Gorny RL, Reponen T, Willeke K, Schmechel D, Robine E, Med 46:596–601. as a disinfectant. Using a variety of sampling Boissier M, et al. 2002. Fungal fragments as indoor air bio- Vojta PJ, Friedman W, Marker DA, Clickner R, Rogers JW, and analytical methods, we observed airborne contaminants. Appl Environ Microbiol 68:3522–3531. Viet SM, et al. 2002. First National Survey of Lead and Green BJ, Sercombe JK, Tovey ER. 2005. 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Environmental Health Perspectives • VOLUME 114 | NUMBER 12 | December 2006 1889 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Environmental Health Perspectives Pubmed Central

Mold and Endotoxin Levels in the Aftermath of Hurricane Katrina: A Pilot Project of Homes in New Orleans Undergoing Renovation

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Research Mold and Endotoxin Levels in the Aftermath of Hurricane Katrina: A Pilot Project of Homes in New Orleans Undergoing Renovation 1 2 3 4 3 5 Ginger L. Chew, Jonathan Wilson, Felicia A. Rabito, Faye Grimsley, Shahed Iqbal, Tiina Reponen, 6 7 8 2 Michael L. Muilenberg, Peter S. Thorne, Dorr G. Dearborn, and Rebecca L. Morley Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York, USA; 2 3 4 National Center for Healthy Housing, Columbia, Maryland, USA; Department of Epidemiology, and Department of Environmental Health, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana, USA; Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio, USA; Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA; Department of Occupational & Environmental Health, The University of Iowa, College of Public Health, Iowa City, Iowa, USA; Department of Environmental Health Sciences, Case Western Reserve University, Cleveland, Ohio, USA sustained between 0.3 and 1.8 m of flood BACKGROUND: After Hurricane Katrina, many New Orleans homes remained flooded for weeks, damage from Hurricanes Katrina and Rita. promoting heavy microbial growth. Three specific objectives of the demonstration were a) to make recommendations for safe OBJECTIVES: A small demonstration project was conducted November 2005–January 2006 aiming to recommend safe remediation techniques and safe levels of worker protection, and to characterize reentry into a home and safe removal of flood- airborne mold and endotoxin throughout cleanup. damaged furnishings and building materials, including levels of worker protection; b)to METHODS: Three houses with floodwater lines between 0.3 and 2 m underwent intervention, including disposal of damaged furnishings and drywall, cleaning surfaces, drying remaining struc- characterize the distribution of airborne mold ture, and treatment with a biostatic agent. We measured indoor and outdoor bioaerosols before, and endotoxin (a cell wall component of gram- during, and after intervention. Samples were analyzed for fungi [culture, spore analysis, polymerase negative bacteria) throughout all phases of the chain reaction (PCR)] and endotoxin. In one house, real-time particle counts were also assessed, cleanup; and c) to comment on the practicality and respirator-efficiency testing was performed to establish workplace protection factors (WPF). of the overall cleanup process. To this end, RESULTS: At baseline, culturable mold ranged from 22,000 to 515,000 colony-forming units/m , Enterprise Community Partners and the spore counts ranged from 82,000 to 630,000 spores/m , and endotoxin ranged from 17 to 139 NCHH, in collaboration with Neighborhood endotoxin units/m . Culture, spore analysis, and PCR indicated that Penicillium, Aspergillus, and Housing Services of New Orleans and several Paecilomyces predominated. After intervention, levels of mold and endotoxin were generally lower partners from academic institutions, studied (sometimes, orders of magnitude). The average WPF against fungal spores for elastomeric respira- these issues as part of the demonstration pro- tors was higher than for the N-95 respirators. ject, which was conducted between November CONCLUSIONS: During baseline and intervention, mold and endotoxin levels were similar to those 2005 and January 2006. found in agricultural environments. We strongly recommend that those entering, cleaning, and repairing flood-damaged homes wear respirators at least as protective as elastomeric respirators. Materials and Methods Recommendations based on this demonstration will benefit those involved in the current cleanup Selection of homes. Three single-family houses activities and will inform efforts to respond to future disasters. in the Gentilly district of New Orleans were KEY WORDS: endotoxin, flood, fungi, mold, Hurricane Katrina, New Orleans, remediation, selected to participate in the project. Most of respirators. Environ Health Perspect 114:1883–1889 (2006). doi:10.1289/ehp.9258 available via the areas in Gentilly lie 0.5–4 m below sea level http://dx.doi.org/ [Online 24 August 2006] [Greater New Orleans Community Data Center (GNOCDC) 2006a]. Eighty-five per- Hurricane Katrina, which occurred on affordably removed from the flooded homes cent of the total households in this area suffered 29 August 2005, caused the breach of several prior to building restoration. On 27 October some degree of damage, and 71% of households levees surrounding New Orleans, Louisiana, 2005, the National Center for Healthy and left over 75% of the city underwater. A Housing (NCHH) convened a meeting to Address correspondence to G.L. Chew, Mailman storm surge from Hurricane Rita several weeks examine options for flood cleanup procedures School of Public Health, Columbia University, 60 later reflooded many areas of the city. In the and air sampling. Attendees included building Haven Ave., B-1, New York, NY 10032-4206 USA. Telephone: (212) 305-1692. Fax: (212) 305-4012. aftermath of these disasters, homes were sub- materials scientists, mold remediation experts, E-mail: [email protected] merged in flood water for several summer members of community-based organizations, This work was funded by Enterprise Community weeks, resulting in severe mold and bacterial industrial hygienists, clinicians, housing pol- Partners with support from the Robert Wood growth, both of which can lead to a panoply of icy makers, and environmental epidemiolo- Johnson Foundation, NeighborWorks America, respiratory health effects [Institute of Medicine gists from across the country (including areas Swetland Center for Environmental Health, Case (IOM) 2004]. Although several studies have affected by Hurricane Katrina). The atten- Western Reserve University, the University of Iowa Environmental Health Sciences Research Center assessed markers of mold and bacteria in damp dees drew on a body of guidance documents [National Institutes of Health (NIH) grant P30 and water-damaged homes (IOM 2004), there for flood cleanup and mold remediation ES05605], National Institute for Occupational Safety is a dearth of literature documenting the levels [American Red Cross and Federal Emergency and Health NORA Research Program of the of these agents in homes that received sus- Management Agency 1992; Centers for University of Cincinnati Education and Research tained flooding (Ross et al. 2000). Disease Control and Prevention (CDC) 2005; Center Grant (T42/CCT510420), and Columbia New Orleans and the surrounding com- Louisiana State University 2005; New York University’s National Institute of Environmental Health Sciences Center for Environmental Health in munities currently face difficult decisions City Department of Health and Mental Northern Manhattan (P30 ES009089). G.L.C. is an regarding whether or not to demolish large Hygiene 2002; U.S. Environmental Protection NIH National Center on Minority Health and numbers of damaged homes. Many factors Agency (EPA) 2001). Health Disparities fellow. will be taken into consideration when those The overall purpose of this demonstration The authors declare they have no competing decisions are made, including the question of was to assess the efficacy of flood cleanup pro- financial interests. whether mold and bacteria can be safely and cedures in three houses in New Orleans, which Received 11 April 2006; accepted 24 August 2006. Environmental Health Perspectives • VOLUME 114 | NUMBER 12 | December 2006 1883 Chew et al. were severely damaged or destroyed by flooding meter with a probe (J-LITE Moisture Meter, using sponge mops and hand sponges to wash from Hurricane Katrina (GNOCDC 2006b). Delmhorst Instrument Company, Towaco, down surfaces with a non-trisodium phosphate To be included in the demonstration, a NJ); moisture readings > 22% were considered solution of sodium sesquicarbonate detergent house had to be flooded with < 2 m of water, saturated, and those < 15% were considered and 15% dilution of household chlorine structurally sound, and located in an area likely dry (U.S. Department of Agriculture 1999). bleach. In all three houses, dry cleaning was to be rebuilt. Owners were required to have The supervisors determined whether electrical conducted before wet cleaning. In house 2, all flood insurance deemed adequate to rebuild service, if operable, was safe and verified that surfaces including all framing members were their house and intentions to rebuild. The first there were no water or gas leaks. wet cleaned. In houses 1 and 3, workers wet house was selected when an employee of a In house 1, surfaces were relatively dry at cleaned only hard, nonporous surfaces (e.g., New Orleans–based nonprofit housing orga- the time of the demonstration, with no stand- tubs, sinks, toilets, tile flooring). nization volunteered his house for the pro- ing water. Possessions with visual mold and Biostat treatments. After cleaning, the three ject. Neighborhood Housing Services, a limited value to the owner of house 1 were houses received biostat treatment with one of chartered member of NeighborWorks discarded. Other hard surface possessions were two borate formulations to prevent future America (Washington, DC), identified two cleaned outside with a bleach–detergent solu- emergence of mold. House 1 was treated with additional homeowners whose houses met the tion and then packed in boxes and moved to Bora-Care (Nisus Corp., Rockford, TN); inclusion criteria. the second floor of the house. House 2 had house 2 was treated with Bora-Care in half the At house 1, the homeowner selected the been closed since Hurricane Katrina and was house and Termite Prufe (Copper Brite, Inc., contractor to complete the work. At houses 2 still relatively wet at the start of the project, Santa Barbara, CA) in the other half; and and 3, Neighborhood Housing Services of with standing water, wet furnishings, and plas- house 3 was treated with Termite Prufe. The New Orleans selected the contractors and ter and drywall surfaces saturated with water. active ingredient in both Bora-Care and supervised the activities, with support from the In house 3, personal belongings, furniture, Termite Prufe is disodium octoborate tetra- NCHH and Urban Renovation Consultants. and lower cabinets had been removed by the hydrate. Both products are fungicides registered Urban Renovation Consultants and the time of the initial inspection. The carpet and by the U.S. EPA. Bora-Care was mixed with NCHH, as well as its national advisory work padding were wet, and the drywall was satu- water (1:3 or 1:4) and sprayed onto all lumber group, developed the construction specifica- rated within 0.3 m of the floor. Details of the sheathing to the point of wetness in confor- tions used at the three houses. baseline conditions and demonstration activi- mance with the manufacturer’s instructions. Personal protective equipment. All workers ties are listed in Table 1. Termite-Prufe (0.45 kg powder to 3.8 L water) and supervisors wore N100 filtering facepiece Deconstruction. Deconstruction at all was applied to all exposed interior surfaces at respirators, nonwoven polypropylene dispos- houses included removing carpet or otherwise 18.7 m per 3.8 L, working from ceiling to able coveralls, and gloves during the property clearing floors down to the finished flooring and floor. The two formulations differ significantly inspection. During property removal and removing insulation, nails on studs, and lower in cost after mixing (Bora-Care was 2.5 times deconstruction, some workers also used half- cabinets, if present. At house 1, bathroom toi- more expensive than Termite Prufe). face HEPA (high-efficiency particulate air) fil- lets, sinks, and bathtubs were also removed. At Drying. Windows in houses 2 and 3 were ter air-purifying respirators (some equipped house 2, workers also removed upper cabinets. left open to allow cross-ventilation to dry the with organic solvent filters) and goggles. Cleaning and sanitizing. Workers cleaned moisture introduced by the biostat treat- Baseline inspection. The supervisors visu- and sanitized all three houses with a combina- ments. All possessions had been removed ally inspected each house for roof leakage, tion of dry-cleaning and wet-cleaning steps. from these houses, so security was not a con- standing water, and the extent of mold on Workers conducted dry cleaning by bristle cern. In house 1, some possessions were walls, cabinets, floors, doors, trim, appliances, brushing studs and other framing members to stored on the second floor, thus windows equipment, and heating ventilation/air condi- remove visible mold growth and then vacuum- were closed, but the upstairs ceiling fan was tioning ductwork. The moisture content of ing the same surfaces with a HEPA filter used. No mechanical dehumidification was the wood studs was tested using a moisture attachment. Wet cleaning was completed by used in any of the houses. Table 1. Baseline conditions and demonstration activities in houses. Baseline description Removal of flood-damaged items Cleaning Drying Biostatic agent used House 1 Built in 1987 Owner moved some cleaned Durable furnishings were wet- Owner left an upstairs Bora-Care (1:3 dilution) Two-story, slab on grade with personal belongings (clothes, cleaned, wiped dry, and placed ceiling fan on throughout attached apartment on the items in cardboard boxes) to the in storage inside the home the duration of the first floor second floor of the home for Only concrete and vinyl floors and demonstration project, but Water line at 0.3 m above floor storage countertops were wet-cleaned windows were closed Roof had been patched with a Bottom 1.2 m of drywall was Ceiling was not dry-cleaned temporary tarp before removed initiating flood cleanup Electricity operational House 2 Approximately 100 years old Furnishings and appliances were All surfaces were wet- and dry- Windows left open for Bora-Care (1:4 dilution) in One-story raised home with too damaged to salvage, so cleaned 2 weeks before applying a front half of home plywood underlayment on workers removed all furnishings biostat treatment 0.6-m piers for disposal Windows left open after Termite Prufe in back half Water line at 1.8 m above floor Drywall was removed floor to application of biostatic of home Electricity not operational ceiling agent House 3 Built in 2004 Owners had removed all personal All surfaces were dry-cleaned Windows left open after Termite Prufe One-story raised home with belongings, furniture, appliances, Only toilets, sinks, bathtubs, and application of biostatic plywood underlayment on and lower kitchen cabinets prior vinyl floors were wet-cleaned agent 0.9-m piers to the demonstration Water line at 0.6 m above floor Drywall was removed floor to Electricity not operational ceiling 1884 VOLUME 114 | NUMBER 12 | December 2006 • Environmental Health Perspectives Mold and endotoxin in New Orleans houses Air sampling. We conducted air sampling instrument measured the number of particles Samples were vortexed, and 100-µL aliquots during three time points for each home: in 15 size ranges, from 0.3 to 20.0 µm. We (undiluted, 1:10, and 1:100 dilution) were a) before intervention (i.e., day 1), b) during used an averaging time of 1 min. spread-plated onto two types of culture media: intervention (i.e., day 1 or 2), and c) after inter- We performed respirator-efficiency testing dichloran glycerol and malt extract agar. vention (i.e., day 36, 23, and 15, respectively, by measuring workplace protection factor Culture plates were incubated at two different for houses 1, 2, and 3). The preintervention (WPF) against fungal spores collected in temperatures: 25°C for 7–10 days or 37°C for sampling for house 1 occurred 1 day after some house 3. The institutional review board of The 2–3 days. For each type of media and each items were removed from the house, but before University of Cincinnati approved this sam- temperature, the plates with nearest 10–30 work commenced on the second day. For pling protocol, and informed written consent colonies were counted. Culturable fungi were houses 2 and 3, the preintervention sampling was obtained by the university investigator reported in colony-forming units (CFU). occurred either 1 day or a few hours before who wore the respirators. We tested two types Fungal spore counts. We analyzed fungal demonstration commenced. Intervention sam- of respirators: a disposable N-95 filtering face- spores by direct microscopic examination of pling occurred within a few hours of removal of piece respirator (model 8110; 3M, St. Paul, 27% of the impaction surface using transverse mold-laden drywall. Postintervention sampling MN) and an elastomeric half-facepiece respira- scans across the spore deposit at 400× magni- occurred between 1 and 2 weeks after borate tor (North 5500-30 with North filter cartridge fication. Larger, infrequently recovered spore solution was applied. Table 2 summarizes the gas and vapor with P100 particulate filter; types were counted by scanning the full air sampling activities conducted in each home. North Safety Products, Cranston, RI). The impaction surface at 200× magnification. In Indoor samples. Using battery-operated experimental protocols and the N-95 filtering situations with very high spore concentra- air sampling pumps (AirChek 2000; SKC, facepiece respirator were as described in an tions, where resulting spore densities were Inc., Eighty Four, PA), we sampled the living agriculture study by Lee et al. (2005). In brief, extreme, fewer transverse scans were per- room air for 20 min at a flow rate of the subject was fit-tested before the experi- formed using a 120-µm reticule (for example, 2.5 L/min with 2.0-µm pore Teflon filters ment using the Portacount method (TSI, Inc., 0.017% of the deposit was scanned in one (Omega Specialty, Inc., Chelmsford, MA) St. Paul, MN). The subject wore the test res- sample). Most spores were identified by housed in 37-mm cassettes. In some houses, pirator, which was connected to a newly devel- genus; Aspergillus, Penicillium, Eurotium, and additional samples were collected upstairs oped personal sampling setup, for 30 min. In Paecilomyces are difficult to discern by this (house 1) and in the bedroom (house 3). The the sampling setup, fungal spores were col- method and were grouped into one category. pumps were attached to a tripod 1.2–1.35 m lected from inside and outside the respirator Polymerase chain reaction (PCR). Aliquots above the floor, with the sampling cassette onto polycarbonate filters. Concentration of of the Teflon filter extracts were analyzed by P open to the center of the room. Using fungal spores (spores per cubic meter) was & K Microbiological Services, Inc. (Cherry high-flow (15 L/min) air sampling pumps determined through microscopic counting of Hill, NJ) for species-specific quantification (Environmental Monitoring Systems, Inc., the filters (Adhikari et al. 2003; Lee S-A et al. using quantitative PCR (qPCR) following the Charleston, SC), fungal spores were collected 2006). WPF was calculated by dividing the methods previously described by Haugland in the living room air using BioCell impaction fungal spore concentration inside the respira- et al. (2004) and Vesper et al. (2004). cassettes (GrafTech, Inc., Brighton, MI) for tor by that outside the respirator near the sub- Reference controls were used as positive quanti- 2 min pre- and postintervention, and 1 min ject’s breathing zone. The test was repeated tative controls. Independent qPCR analyses during intervention. Lack of electricity pre- twice with the N-95 respirator and four times were performed using primers and probes vali- cluded postintervention indoor and outdoor with the elastomeric respirator. dated specifically for the 23 species/species sampling with the high-flow pumps for houses Outdoor samples. To collect outdoor sam- groups of interest: Acremonium strictum, 2 and 3. Sampling trains were pre- and post- ples, we placed the battery-operated AirChek Alternaria alternata, Aspergillus flavus/oryzae, calibrated, and the average flow rate was used 2000 pumps 3 m outside the front door for Aspergillus fumigatus, Aspergillus niger, in calculations of volume of air sampled. collection of one preintervention sample for Aspergillus ochraceus, Aspergillus sydowii, Particle counts were measured in real-time house 3, one sample during the intervention Aspergillus ustus, Aspergillus versicolor, Eurotium for house 3 (before and during intervention) for house 2, and postintervention samples for (Aspergillus) amstelodami, Chaetomium globo- using an optical particle counter (model 1.108; all three homes. We also collected samples sum, Cladosporium cladosporioides, Memnoniella Grimm Technologies, Douglasville, GA). This before and during intervention using the high- echinata, Paecilomyces variotii, Penicillium flow pumps placed at 3 and 10 m outside the aurantiogriseum, Penicillium brevicompactum, Table 2. Air sampling activities conducted for front door. Also, some outdoor samples were Penicillium chrysogenum, Penicillium purpuro- houses (indicated by X). not collected during inclement weather genum, Penicillium variabile, Scopulariopsis Activity House 1 House 2 House 3 because of concerns regarding technician safety brevicaulis/fusca, Stachybotrys chartarum, Indoor air (culturable fungi, endotoxin, PCR) and equipment damage. Trichoderma viride/koningii, and Ulocladium Prework X X X Field blanks. On sampling days when botrytis. During work X X X intervention occurred, we collected a blank Endotoxin. Aliquots of the Teflon filter Postwork X X X BioCell to assess fungal spores that could have extracts were analyzed for endotoxin by the Indoor air (fungal spores) been on the collection media before sampling, kinetic chromogenic Limulus amebocyte lysate Prework X X X that were introduced in the moments before assay (Thorne 2000; Vojta et al. 2002). Levels During work X X X Postwork X starting and after stopping the pump, and dur- of endotoxin were reported in endotoxin Outdoor air (culturable fungi, endotoxin, PCR) ing sample transport. The BioCell cassette was units (EU). Prework X opened for 1 min in the house (without attach- During work X Results ment to a sampling pump), and then sealed. Postwork X X X All blanks were negative for fungal spores. Comparison of levels before, during, and after Outdoor air (fungal spores) Analytical methods. Culture of fungi. intervention. The baseline levels of mold and Prework X X X During work X X X Teflon filters were placed in 5 mL pyrogen- endotoxin, some of which varied by orders of Postwork X free water with 0.05% Tween 20 in sterile magnitude within homes, are shown in Respirator-efficiency testing X plastic tubes and shaken for 1 hr at 25°C. Table 3. The preintervention samples for Environmental Health Perspectives • VOLUME 114 | NUMBER 12 | December 2006 1885 Chew et al. house 1 were taken after some belongings had the Basidiomycota. Culture at 25°C and spore component of gram-negative bacteria, we been removed the previous day, yet the baseline counting showed that Trichoderma was com- speculate that the bacteria were killed but that levels were still generally below those of the monly recovered in the indoor air samples. A endotoxin remained in the settled dust after other two houses. What is clear from Figure 1 is PCR probe for Trichoderma virde/koningii had the intervention. Nonetheless, the levels of that postintervention levels of all bioaerosols in a low recovery, suggesting that other methods mold (as determined by three different each house tended to be lower than at pre- may have been detecting another common methodologies) were drastically reduced after intervention, except endotoxin in house 2, Trichoderma species such as Trichoderma the intervention in house 2. which was moderately elevated, and culturable harzianum. A strength of our study was the multi- mold in house 1, which had postintervention Particle counts. Figure 4 presents results pronged assessment of mold exposure. From levels similar to those collected preintervention. of total particle counts, and Figure 5 shows our data, it is clear that the use of any one of Because generators were not available at all sam- size-selective particle concentrations. For the the analytical methodologies (culture, pling periods at houses 2 and 3, several mold data analysis, we combined the 15 channels of microscopy, or PCR) would have shown that spore count measurements could not be col- the optical particle counter into four size baseline levels of mold were high compared lected. However, house 1 had spore measure- ranges: 0.3–0.8, > 0.8–3.0, > 3.0–7.5, and with agricultural, industrial, or other home ments from all three time points, and the > 7.5–20.0 µm. Results show that number environments. However, each analytical pattern was similar to that of the culturable concentrations of particles of all sizes method gave different insight that we hope fungi, PCR, and endotoxin results; levels increased during intervention, most clearly for will inform future investigations in homes in increased during work and then decreased after particles > 0.8 µm. In contrast, during the New Orleans and in other environments. In intervention (Figure 2). lunch break, the concentration of particles contrast to culture methods to detect and enu- Differences and similarities in fungal taxa > 0.8 µm decreased almost to the same level merate fungi, spore microscopy and qPCR do profiles. Interpretations of the predominant as measured before the intervention. not require viable fungal elements. In addi- fungi recovered in the air samples differ Efficiency of respiratory protection. The tion, spore microscopy and qPCR detect not depending upon the type of analysis. As WPF values for the two types of tested respira- only dead fungi but those that compete poorly shown in Figure 3, Aspergillus, Paecilomyces, tors are presented in Table 4. The average on the various media used to grow fungi. The and Penicillium were among the most fre- WPF against fungal spores for the elastomeric culture-based analyses (on both malt extract quently detected fungal taxa determined by all respirator was higher than that measured for agar and DG18 agars) can underestimate the three methodologies (culture, PCR, and spore the N-95 filtering facepiece respirator. populations of some Aspergillus species by counting). Most of the spore count was due to orders of magnitude when compared with Discussion Aspergillus/Pencillium spores. In house 1, qPCR (Meklin et al. 2004). In contrast, Stachybotrys was recovered in the living room A critical finding of the present study is that in Basidiomycota spores (the common mushroom and in outdoor air during the intervention, homes that held flood waters for several weeks, is in this fungal phylum) generally do not grow but decreased to nondetectable levels by the our flood cleanup techniques were associated well on culture plates, and a probe was not postintervention sampling visit. Cladosporium with a reduction in mold and endotoxin lev- available for PCR analysis; therefore, only spore was not frequently recovered from culture; els. In all three homes, the interventions microscopy enabled detection of this potentially however, it was frequently detected by PCR decreased mold levels and in some cases, the allergenic group of molds (Horner et al. 1995; and spore counts, but at low concentrations decreases were several orders of magnitude. In Lehrer et al. 1986). The low frequency of relative to Aspergillus and Penicillium. In fact, the only measure that increased from pre- Trichoderma and Alternaria detection by PCR addition, spores of Curvularia and the intervention to postintervention was endo- compared with the moderate to high frequency Basidiomycota (including rusts, smuts, and toxin in house 2. This house had the most of recovery by direct microscopy and, to a lesser basidiospores) were identified by microscopy. extensive flood damage, and during the inter- extent, culture likely reflects the airborne pres- Neither PCR nor culture methods used in this vention, endotoxin was higher than in the ence of taxa (e.g., T. harzianum and Alternaria analysis had the ability to measure spores of other houses. Because endotoxin is a cell wall tenuissima) for which PCR probes were not used or available. The spore microscopy also Table 3. Baseline indoor concentrations of mold and endotoxin. revealed that Curvularia was common in the houses. Although a PCR probe for Curvularia Total culturable mold Total mold spore PCR results 3 a 3 3 3 was not available for analysis of these samples, (CFU/m ) counts (spores/m ) (spore equivalents/m ) Endotoxin (EU/m ) culture analysis should have been able to grow House 1 22,000–46,000 82,381 80,779 43 Curvularia. The low prevalence of culturable House 2 268,000–515,000 202,634 1,039,841 17 House 3 BR = 29,000–59,000 634,651 BR = 77,911 BR = 100 Cladosporium contrasts with the high preva- LR/Kit = 332,000–342,000 LR/Kit = 178,067 LR/Kit = 139 lence, as determined by microscopy and PCR. Cladosporium is one of the most common fun- Abbreviations: BR, bedroom; Kit, Kitchen; LR, living room. The average of samples grown on two different media and incubated at two different temperatures, resulting in four gal taxa recovered indoors and outdoors plates per sample collected. House 1 7 4 10 10 House 2 8 6 10 10 A B C House 3 5 10 Outdoor 6 10 2 0 0 0 10 10 10 Prework Work Postwork Prework Work Postwork Prework Work Postwork Sampling period Sampling period Sampling period Figure 1. Results of filter samples from the three houses using three different analytical methods: total culturable mold (A; results are shown only for those grown on malt extract agar and cultured at 25°C), PCR (B), and endotoxin (C). Work for house 1 is the average of two measurements (upstairs and downstairs); outdoor prework is represented only by house 3; outdoor work is represented only by house 2; and outdoor postwork represents the average of the three houses. 1886 VOLUME 114 | NUMBER 12 | December 2006 • Environmental Health Perspectives Culturable mold (CFU/m ) PCR (spore equivalents/m ) Endotoxin (EU/m ) Mold and endotoxin in New Orleans houses throughout the world (Chew et al. 2001, mold, and endotoxin, suggest that a substan- of 1970). Still, no defined level of mold is 2003; IOM 2004; Levetin 1995; Su et al. tial portion of the particle counts could be listed that warrants a specific level of respira- 2001). Cladosporium competes well with composed of fungal and bacterial material tory protection. An assigned protection fac- many of the other taxa that we recovered, so even during periods of inactivity. tor, which can be used in the initial selection the reason for its decreased culturability in our The choice of respirator depends on the of respirator type, gives the level of the respi- samples remains elusive. expected level of contamination. Currently, ratory protection that a properly functioning At baseline and particularly during inter- there are no threshold limit values for mold respirator or class of respirators would be vention, we observed household levels of mold or endotoxin in the United States; however, a expected to provide to properly fitted and and endotoxin that equaled or surpassed those Dutch occupational health standard for trained users in the workplace (OSHA 2006). in wastewater treatment plants, cotton mills, endotoxin (50 EU/m ) existed for a brief The assigned protection factor for both filter- and agricultural environments (Christiani et al. time (Douwes et al. 2003). Also, excessive ing facepiece and elastomeric half-facepiece 1993; Lee J et al. 2006; Lee S-A et al. 2006; mold can be cited as a health concern by the respirators is 10 (e.g., 5,000,000 particles/m Spaan et al. 2006). Interestingly, the outdoor Occupational Safety and Health Adminis- would be reduced to 500,000 particles/m ) measurements were also higher than expected, tration (OSHA) under their General Duty (OSHA 2006). We found that, in the field, ranging from 10 to 25 EU/m . These exceed Clause (Occupational Safety and Health Act the WPF was lower for the N-95 respirator. the average outdoor endotoxin measurements from 13 Southern California communities of Culture (25°) 0.44 EU/m (Mueller-Anneling et al. 2004). Culture (37°) In addition, the baseline levels of culturable Spores mold in the three houses averaged 352,701 PCR CFU/m , which was much higher than the average (2,190 CFU/m ) or maximum level (48,760 CFU/m ) in homes sampled after the 1993 Mississippi River flood (Ross et al. 2000). The comparison with the Mississippi River flood study may somewhat overstate the disparity between the two floods because sam- pling in the earlier study occurred 1 year after the flood and only 40% of the residents in that study reported flood damage in their homes. Nonetheless, the levels of mold in the homes in the present study were extremely high. Given the level of visible mold observed when we first entered our demonstration homes, we were 0 concerned about the level of respiratory protec- tion required for entry and cleanup, and our Fungal taxa measurements of both the mold levels and the respirator WPFs supported our concern. Figure 3. Frequency of fungal taxa in samples of indoor and outdoor air from the three houses and during By the time we planned the initial visit to different timepoints grouped together. The sample size limited interpretation when stratifying by location house 3, we were able to characterize the par- and timepoints. Culture at 25°C (n = 35); culture at 37°C (n = 35); spore counting (n = 17); and PCR (n = 21). ticle sizes and conduct experiments to test the WPF of a disposable N-95 respirator and an elastomeric half-facepiece respirator. Our data indicate that counts of larger particles During renovation (10 January 2006) decreased drastically during the lunch break, taking almost 30 min to reach the lowest point, and reached counts of 50, 500, and 5,000/L of air (i.e., 50,000, 500,000, and 5,000,000 particles/m ) depending on the Lunch break size range. These data, combined with the measurements of mold spores, culturable 8 House 1 House 2 House 3 6 Outdoor Before renovation (9 January 2006) Prework Work Postwork Sampling period Figure 2. Results of mold spore counts. Only house 1 had an inside postwork measurement. Outdoor pre- work and work levels represent the average of the measurements for the three houses. Spore counts Time for house 1 decreased 77.6% between prework and postwork periods. Figure 4. Total particle concentrations before and during the renovation. Environmental Health Perspectives • VOLUME 114 | NUMBER 12 | December 2006 1887 Cladosporium Aspergillus Penicillium Paecilomyces Chaetomium Stachybotrys Trichoderma Alternaria Basidiomycetes Curvularia Zygomycetes Mold spores/m Percentage of samples with at least one colony Number concentration (no./L) 1436 Chew et al. In a previous study (Lee et al. 2005) in which of WPF data points in the present study is maximum particle penetration of approxi- the WPF against fungal spores was measured low, the results suggest that the elastomeric mately 0.03–0.07 µm (Balazy et al. 2006). in agricultural environments, the geometric half-facepiece respirators offer at least The postintervention findings in house 1 mean and geometric standard deviation of 21 10 times the protection against fungal spores. highlight the critical importance of fully clean- WPF data points was 25 and 9.9, respectively. Because the fungal spore concentrations were ing and drying a house. The upper walls and In addition, the WPF decreased with decreas- extremely high during the renovation, we ceilings in the house were not vacuumed as ing spore size. The values obtained from the question whether the protection offered by the part of the initial cleanup procedures. In addi- N-95 respirator in house 3 were somewhat N-95 filtering facepiece or the elastomeric res- tion, a small water leak saturated a portion of lower than those in agricultural environ- pirators is sufficient. Furthermore, our WPF the concrete floor after work was completed. ments. This could be due the composition of values are based on microscopic counting of Because possessions remained inside, the fungal load in the moldy building where intact spores. Recent studies have shown that house was closed and the humidity levels small Aspergillus/Penicillium spores predomi- exposure to fungi occurs also through sub- could have created a climate hospitable for nated. On the other hand, the WPF for the micrometer fungal fragments (Foto et al. further mold growth. The fact that culturable elastomeric respirator was clearly higher than 2005; Gorny et al. 2002; Green et al. 2005). mold levels in this home were not substan- the values obtained for the N-95 respirator in These particles may penetrate at even higher tially lower after intervention than before is this study and in the previous agricultural rates as intact spores because the filter materi- likely related to these factors. After post- study (Lee et al. 2005). Although the number als commonly used in N-95 respirators have intervention sampling was completed, the water leak in house 1 was fixed and cleaning and mechanical drying was conducted. 0.3–0.8 μm > 0.8–3.0 μm > 3.0–7.5 μm > 7.5–20.0 μm House 1 also offers a cautionary note about the risks involved with leaving some of Before renovation the original drywall in a home. Some flood cleanup guidance suggests that, in homes with 10 minimal flooding, removing drywall on walls to 1.2 m (4 ft is the width of a standard sheet of drywall) instead of to the ceiling can save 4 thousands of dollars in restoration costs (American Red Cross and Federal Emergency Management Agency 1992). However, many homes were submerged for weeks after Hurricane Katrina; although the water may have only wicked from the water line to the first 1.2 m, the homes were usually closed and the summer heat resulted in humidity levels similar to that of a terrarium. In our study, the house with the lowest water line (house 1) had visible mold growth in the wall cavities above 1.2 m after treatment. Although we cannot be certain that the growth would have occurred had cleaning and drying been ade- quate, the potential health risks of leaving the original drywall in the home must be taken During renovation into consideration. The question of whether household bleach is an effective treatment mechanism was one of the most debated topics among the advisory Lunch break group. Although it can have adverse environ- mental health effects, we used a dilute solution of bleach because of widespread concern of bacterial contamination and evidence that it could denature allergens (Chen and Eggleston 2001; Matsui et al. 2003) and possibly inacti- vate mycotoxins (Wilson et al. 2004). Bleach was selected primarily on the basis of federal Table 4. WPF against fungal spores with two types of respirators. WPF Respirator type No. of WPFs GM (GSD) N-95 filtering facepiece 2 5 (3.6) Elastometric half-facepiece 4 40 (2.9) Abbreviations: GM, geometric mean; GSD, geometric Time standard deviation. Each respirator type was tested in one subject. Figure 5. Size-selective particle concentrations before (A) and during (B) the renovation. 1888 VOLUME 114 | NUMBER 12 | December 2006 • Environmental Health Perspectives Concentration (no./L) Concentration (no./L) 1436 Mold and endotoxin in New Orleans houses guidance (American Red Cross and Federal reduced bioaerosols in the demonstration Hung LL, Miller JD, Dillon HK, eds. 2005. Field Guide for the Determination of Biological Contaminants in Environmen- Emergency Management Agency 1992; CDC houses, myriad issues including the qualifica- tal Samples. Fairfax, VA:American Industrial Hygiene 2005) and because it was widely accessible. In tions of those performing the work (including Association. house 2, bleach was applied to the wooden homeowners), depth and duration of flooding, IOM (Institute of Medicine). 2004. Damp Indoor Spaces and Health. Washington, DC:National Academies Press. building members, whereas it was not used in and the availability of electricity and supplies Lee J, Johnson JC, Reynolds SJ, Thorne PS, O’Shaughnessy house 3. Because the postintervention findings can affect the feasibility and ultimately the PT. 2006. Indoor and outdoor air quality assessment of for mold were similar in the two homes, we success of flood cleanup efforts. Our pilot pro- four wastewater treatment plants. J Occup Environ Hyg 3:36–43. are encouraged that intensive dry cleaning fol- ject was not designed for determining whether Lee S-A, Adhikari A, Grinshpun SA, McKay R, Shukla R, Li H, lowed by the application of borates appears to the demonstration homes were safe for reoccu- et al. 2005. Respiratory protection provided by N95 respira- control mold growth. The use of dry cleaning pancy. Rather, we examined the extent to tors against dust and microorganisms in agricultural farms. J Occup Environ Hyg 2:577–585. without wet cleaning the wood had the added which homes that experienced significant and Lee S-A, Adhikari A, Grinshpun SA, McKay R, Shukla R, Reponen benefit of reducing the time of flood cleanup prolonged exposure to flood waters could be T. 2006. Personal exposure to airborne dust and micro- because the workers did not need to allow the satisfactorily cleaned to enable reconstruction. organisms in agricultural environments. J Occup Environ wood to dry before applying borates. Research Future research may include revisiting these Health 3:118–130. Lehrer SB, Lopez M, Butcher BT, Olson J, Reed M, Salvaggio JE. to examine alternatives to bleach is under way. homes after reconstruction to determine 1986. 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Environmental Health Perspectives • VOLUME 114 | NUMBER 12 | December 2006 1889

Journal

Environmental Health Perspectives – Pubmed Central

Published: Aug 24, 2006

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