MOLD REMEDIATION PROCEDURES AT A NEW JERSEY ELEMENTARY SCHOOL

Transcription

1 MOLD REMEDIATION PROCEDURES AT A NEW JERSEY ELEMENTARY SCHOOL M McGuinness * R.K. Occupational and Environmental Analysis, Phillipsburg, NJ, USA ABSTRACT Microbiological remediation procedures at an Elementary School in Central New Jersey are discussed. Significant amplification was noted visually and sampling of air and surfaces confirmed visual observations. Preliminary sampling identified airborne levels of countable fungi that ranged as high as 261,000 str/m 3 with Aspergillus/Penicillium-like species comprising more 90% of the sample loading. Significant amplification was noted in the carpets (>12 million CFU/gram) dominated by either Cladosporium or Penicillium. The specific remedial plan developed by the authors and contractors addressed issues necessary to properly remediate the building and reduce occupant exposures to potentially toxigenic and/or allergenic species of fungi. Active communication procedures between concerned parties were part of the remedial plan as well. The project was successfully completed and the start of the new school year was delayed less than two weeks. Successful completion of this project resulted from appropriate remedial procedures, contractor competence and the cooperation of all concerned parties. INDEX TERMS Bioaerosols, Schools, Building Design and Remediation, Humidity and Moisture Problems INTRODUCTION This study details the procedures employed to address significant microbiological contamination in a 78,000 square foot elementary school. Preliminary assessment and sampling results are briefly summarized. Post-remedial ( clearance ) results are summarized as well. Components of the remedial plan are discussed as well as the issues considered when developing the remediation plan. Remedial project considerations included facility drying; consideration of the results from the initial surveys and microbial sampling; engineering appropriate air pressure differentials and careful evaluation of unplanned air flows that could be created by mechanical movement of air; pathway identification and control; isolation and control of airborne contamination; removal of contaminated porous materials; deep cleaning of remaining materials, surfaces, equipment and finishes; air scrubbing using negative air machines to remove residual airborne contamination; worker and environmental protection; project clearance procedures and reoccupancy procedures and criteria. The opening of the school following summer vacation was delayed due to the microbiological conditions in the school and thus the case received much media attention and scrutiny. * Author mguinni@nni.com 745

2 METHODS Preliminary assessment included interviews with staff to identify the source(s) of uncontrolled moisture, a walk-through inspection of all rooms, an brief evaluation of the HVAC system, collection of moisture readings from various building materials and finishes, characterization of the substrates where mold was present in order to properly identify an appropriate remedial strategy and collection of samples to identify source organisms and understand the building ecology of the recent past. We collected samples for culturable and countable fungi in air and on surfaces. In some cases, particularly in the pre-remediation phase, bulk samples of carpet dust or other materials were collected and analyzed for culturable fungi or bacteria as well. Culturable air samples for fungi were collected using an Andersen N-6 with a flow rate of 28.3 liters per minute (LPM) and MEA agar. Countable samples for airborne spores were collected with Air-o-cell cassettes and air samplers calibrated to 15 LPM. Surface samples for culturable fungi were collected using sterile swabs and nutrient solution. Surface samples for countable material were collected using sticky tape and direct microscopic analysis by the contract laboratory. Remedial procedures were designed based on the authors past experience completing these types of large building projects with widespread mold contamination, good engineering and industrial hygiene practices and procedures, the results of the building surveys and consultant and contractor professional judgment. Design considerations addressed the method necessary to dry wet building materials, identification of appropriate remedial methods to address the different types of contaminated materials and project staging. RESULTS SPECIFICATIONS AND JOB SCOPE Project Specifications were performance-based as opposed to prescriptive-based in order to allow the remedial contractors to have input into the remedial process. We believe that contractors should not be told how to complete a project as much as he should be allowed to determine the best approach to accomplish the work. We required submission of a work plan by prospective remedial contractors that described how they were going to approach the project and achieve clearance after the project was completed. The plans were then reviewed, modified (in some cases) and approved by the consultant. The approved work plans then became part of the contract between the Board of Education and the successful contractors. Items that we did specify to the contractors included a general scope of work and the goal of the project (i.e. removal of all existing contamination in both the air and on surfaces); worker protection (single or double layers of protective suits (based on work activity), safety shoes and hard hats, impervious gloves, appropriate employee training); respiratory protection (full face piece Powered Air Purifying Respirator (PAPR) with P-100 cartridges for active deconstruction activities, full face piece air-purifying respirator with P-100 for initial set up and gross cleaning activities, and disposable N-95 respirators for final cleaning procedures); appropriate medical surveillance and worker training for workers required to use respiratory protection; specific training relative to mold remediation activities (minimum of 20 hours of mold remediation training and appropriate OSHA training); minimum air pressure differentials between work areas and adjacent areas (5 Pascals) and the requirement that pressure differentials be data-logged; work area isolation procedures including installation of critical barriers and HVAC shut down. 746

3 Other specified items included submittals relative to insurance coverage, references, required OSHA written programs, MSDS s for any chemicals proposed to be employed and a project Work Plan; compliance with applicable codes and regulations (OSHA, FIFRA, DOT, EPA, etc.); waste preparation and disposal (no biohazard labels on waste bags); final cleaning procedures; air scrubbing requirements; and clearance criteria (scrupulously clean work areas, no visible dust or dirt, dry building materials, correction of causes of uncontrolled moisture, low/no indicator species or identified contaminants, favorable comparison with reference locations and a fungal spectrum in samples collected in work areas not indicative of unusual microbiological conditions). Since we do not prefer to tell a contractor how to do his job, we did not specify how the contractor should dry the facility, what materials should be removed, how the materials should be removed; how much material to remove; what materials required cleaning (as opposed to removal); how to protect previously cleaned areas from cross contamination from adjacent work areas; biocide use; whether to employ a decontamination unit; regulated area and work area set-up; and emergency response procedures. We did, however, work with both remedial contractors to address these issues and arrive at final contract documents. Due to the emergency nature of this project, the fact that time was of the essence and the fact that the opening of school for the new school year would be delayed, some of our usual procedures were not implemented. For example, one of our requirements for prospective contractors bidding one of our large jobs is submission of a proposed Work Plan outlining procedures the contractor intends to follow on a given project. This Plan was not specified as a submittal. Instead, we met with both pre-selected contractors, completed a walk-through inspection of the entire school and then collaborated to achieve an acceptable remedial approach that made sense to all parties. The school was divided in two work areas of approximately equal area (35,000 ft 2 each) and work proceeded on an emergency basis so as not to require a public bidding process. All parties agreed to uniform unit pricing with a not to exceed cap. RESULTS PRELIMINARY INVESTIGATION An initial investigation in late August 2000 revealed that carpeting in one wing of the school was a reservoir of significant visible mold growth due to operation of the air conditioning system during and after wet extraction of the carpets. The resulting low temperatures and elevated relative humidity in the school inhibited drying of the carpet and mold growth resulted. Carpets were still saturated with moisture 5 days after the extraction and were covered with visible mold. While this localized problem was being evaluated and sampling results were pending, the entire air conditioning system failed the Friday evening prior to the long Labor Day weekend when the building was unoccupied. The result was that hot, humid outdoor air entered the building and condensed on cold surfaces. By the time Administrative, Custodial and Instructional staff entered the building on the following Tuesday, mold growth was rampant in the school. Most remaining carpet that had not been extracted and was not a reservoir of mold prior to the holiday weekend was now covered with mold. Mold was also amplifying on desks, books and other classroom materials, painted walls and other surfaces, books in the Library were 747

4 affected and localized and general mold amplification was noted in essentially all areas of the school including each of the four wings in the school plus offices and other administrative areas. Moisture levels in carpets were saturated in many locations. Levels in other materials were variable but did indicate the need for dehumidification of the air and localized drying of other materials. RESULTS PRELIMINARY AND CLEARANCE SAMPLING Phase I Sample Results August 19, 2000 Again, the results of visual assessment, moisture surveys and limited air, bulk and surface sampling indicated the need for immediate action. The opening of school was delayed and remedial measures were immediately undertaken. Two contractors were selected to remediate half the school each and work progressed using 2 crews per shift for two shifts per day. 1. Range of airborne countable fungi: 766 str/m 3 in the indoor reference location to 5,032 str/m 3 ; outdoor reference sample yielded 3,227 str/m 3. Asp/Pen dominated the indoor samples. 2. Range of culturable fungi in air: 1,013 CFU/m 3 to 3,263 CFU/m 3. The Outdoor Reference sample yielded 2,002 CFU/m 3. Cladosporium was the dominant (most prevalent) fungi identified in all of the samples collected. Levels of Cladosporium, Penicillium, and Fusarium measured in one room were elevated with respect to the outdoor reference sample. 3. Range of bulk samples collected from the extracted carpets: 67,097 CFU/g to 12,846,670 CFU/g with the notable presence of Aspergillus spp., Penicillium spp., and Cladosporium). 4. Range of bulk samples for culturable bacteria in the carpet: 125,161 CFU/g t o 1,571,667 CFU/g with the notable presence of indicator species of bacteria (Shewanella putrefaciens and Gram-negative spp). Phase II Sampling Results, Post-Labor Day September 5, Range of results for airborne countable fungi: 2,516 str/m 3 in B Wing to 260,981 str/m 3 in C Wing. Aspergillus/Penicillium-like fungal spores were the dominant spores identified in the samples collected from C Wing (250,771 str/m 3 ), the A Cluster composite (66,282 str/m 3 ), and the far end of C Wing (51,446 str/m 3 ). 2. Range of surface samples of settled dust: a few to massive Aspergillus, Cladosporium, Curvularia, and Penicillium-like spores Phase III Initial Clearance Sampling September 11, Range of countable airborne fungal material: 718 str/m 3 in the composite sample collected in C Wing to 3,254 str/m 3 in composite sample collected from the A Cluster. The Outdoor Reference sample yielded 2,249 str/m 3. Ganoderma and Cladosporium were the co-dominant species outdoors and Cladosporium was dominant in all indoor samples. 2. Unusual levels of fungal structures (Cladosporium and Asp/Pen spp.) were elevated with respect to the outdoor reference sample in the A Cluster and D Wing. Unusual results in the form of levels of Cladosporium above outdoors and Aspergillus/Penicillium-like spores were seen. 3. Samples of settled dust were collected and analyzed for countable fungi: a trace to many Aspergillus, Chaetomium, Cladosporium-like spores were identified in certain locations. 748

5 4. It was recommended that all surfaces in these rooms be cleaned again to further reduce fungal loads and that the air should be scrubbed using air filtration machines (negative air machines) that are set up to re-circulate the air in those areas requiring additional cleaning. 5. Following completion these recommendations, school was re-opened with the understanding that follow-up sampling would be conducted once the heating season began and that the School Nurse and parents would closely monitor occupant health. Follow-up Sampling November 16, Range of samples for countable fungal material: 255 str/m 3 in the composite sample collected from the A Cluster to 817 str/m 3 in the Media Center composite. The outdoor reference sample yielded 1,991 str/m 3. Cladosporium-like spores and basidiospores were the dominant (most prevalent) or co-dominant fungal structures identified in almost all of the samples collected indoors, both in the air and on surfaces. 2. Based on these results and a second visual inspection, we believed that the HVAC system was not a significant source of occupant exposures to bioaerosols during the heating season and continued efficient cleaning for health procedures resulted in a hygienic environment that did not exhibit unusual microbial conditions. 3. Range of samples for culturable (viable) fungi: 106 CFU/m 3 in the Art Room to 353 CFU/m 3 in C1. The Outdoor Reference sample yielded 412 CFU/m 3. Cladosporium was the dominant (most prevalent) fungi identified in all of the samples collected. DISCUSSION The final project scope involved removal of all carpets and ceiling tiles, wallboard and classroom materials and books with visible mold growth. All materials on bulletin boards were removed, much to the dismay of staff members who worked very hard the previous week to get them ready for the opening of school. Contaminated hard surfaces such as desks, tile floors, painted block walls, shelving and in fact all remaining horizontal and vertical surfaces were repeatedly HEPA vacuumed, damp wiped with a mild disinfectant solution and HEPA vacuumed again. The school was essentially deep-cleaned using HEPA vacuums and HEPA air scrubbers to address both residual air and surface contamination. Visual inspections were conducted weekly for two weeks. Prior to collecting clearance samples the work areas had to pass a visual inspection, a white glove test and affected building materials and furnishings that remained had to be dried to within 10% of background levels consistent with moisture levels of reference materials dried in a test chamber. This project demonstrates that proper planning and cooperation among the building owner, project engineers and consultants, and contractors can result in a successful mold remediation project. The engineers did not specify all contractor activities but rather those that needed to be specified to provide guidance to the contractors. The contractors, on the other hand, specified their own procedures in those areas where they are the experts. The final project specifications were a combination of both contractor and engineer expertise. 749

6 CONCLUSIONS After remedial procedures were completed, the indoor environment did not exhibit the same microbiological conditions that resulted in the decision to delay the opening of the school and remove mold contamination. Contractors removed significant levels of Asp/Pen spp. and other fungal indicator species by removing or cleaning growth sites, scrupulous cleaning, air scrubbing and drying wet materials. Common, phylloplane fungi dominated the post-remedial indoor environmental samples. According to school officials (internal discussion with the Superintendent and Business Administrator), Staff attendance rates increased 4% over the past year and student attendance rates were up 8%. Attendance rates at the school were also the highest among the District s 6 schools. The authors believe that part of this fact is due to the deep cleaning the school received. Not only did the remediation result in a reduction of airborne and surface mold contamination, but it also significantly reduced overall dust and allergen levels and resulted in significantly improved building hygiene. ACKNOWLEDGEMENTS The author would like to thank Mr. Mike Poll and Mr. John McCormick of the Sayreville Board of Education for their help in completing this project and for understanding that mold contamination seen on the scale that existed in this school required special remedial procedures and trained personnel. REFERENCES McGuinness, M. and McGuinness, P Mitigation Procedures at Microbially Contaminated Facilities, Proceedings from IAQ 96, Paths to Better Building Environments, pp Atlanta: American Society of Heating, Refrigeration and Air Conditioning Engineers, Inc. Morey, P Microbiological Contamination in Buildings. Proceedings from IAQ 92, Environments for People, pp Atlanta: American Society of Heating, Refrigeration and Air Conditioning Engineers, Inc. Shaughnessy, R. and Morey, P Remediation of Microbial Contamination. In Bioaerosols: Assessment and Control. Macher, J. ed. Cincinnati: American Conference of Governmental Industrial Hygienists. pp NYC Guidelines on the Assessment ande Renmediation of Mold in Indoor Environments. New York City: New York City Department of Health. 750