I. Wainless, U.S. DOL/OSHA, Washington, DC.
Within the last couple of years, concern about indoor exposure to mold has increased along with public awareness that exposure to mold can cause a variety of health effects and symptoms. Based upon OSHA’s mission, which is to protect the health and safety of the American people, OSHA published a Safety and Health Information Bulletin for the remediation and cleanup of mold and moisture problems in buildings.
This session covers recommendations for the prevention of mold growth and measures to protect the health of building occupants and workers involved in mold cleanup. OSHA’s technical assistance document is designed primarily for building managers, custodians, and others who are responsible for building maintenance. It serves as a reference for remediators. Using this document, individuals with little or no experience with mold remediation should be able to make a reasonable judgment as to whether the situation can be handled in-house. It will help those in charge of maintenance to evaluate an in-house remediation plan or a remediation plan submitted by an outside contractor. Contractors and other professionals, who respond to mold and moisture situations in buildings, as well as members of the general public, can use the Safety and Health Information Bulletin to understand basic remediation procedures.
OSHA’s technical assistance document is intended only as a summary of basic procedures and is not intended, nor should it be used, as a detailed guide to mold remediation. This guidance is subject to change as more information regarding mold contamination and remediation.
M. Latko, Aon Corporation, Glenview, IL.
In 2003, the American Society of Safety Engineers (ASSE) received approval from the American National Standards Institute (ANSI) to initiate development of a canvass standard to address the need for a national consensus standard for guidelines for mold and fungi control and remediation in indoor work environments. This presentation provides the audience with an overview of ASSE’s position regarding mold, worker protection and the indoor work environment, and an overview and update on the ASSE/ANSI standard development progress to date. The author and presenter is the current chair of this committee.
ASSE’s primary focus is worker protection. ASSE’s position statement is the foundation upon which this standard is based and defines ASSE’s current understanding and position regarding mold in the indoor environment at this point in time. The standard is intended to provide the minimum requirements to be followed for the control and remediation of mold and fungi in non-industrial and industrial work environments.
It is ASSE’s belief that mold has become an important safety, health, and environmental issue. EHS professionals are being asked to respond to mold-related issues including development and implementation of preventive measures and programs, identification and quantification of mold contamination in indoor environments, identification and awareness of worker and workplace activities that increase the potential for exposure to mold, and development and implementation of remediation plans and projects to remove mold from indoor workplaces. With EHS professionals conducting such work in the absence of a universally accepted standard from a cognizant authority, ASSE believes there is a need to assist EHS professionals by providing guidelines under which such work can be executed in a manner that provides protection to workers and which does not cause increased risk to building occupants.
G. Rossing, AMEC Earth & Environmental Inc., Portland, OR.
Staff working in a college library reported experiencing various sick building syndrome (SBS)-related symptoms that were associated with working in the building. The building had previously undergone extensive fungal remediation a few years earlier due to failure of the original exterior insulation finish system cladding. The type of symptoms, time of occurrence, frequency, and affected staff members had been well documented by the college’s health and safety department.
An approach was devised for conducting the indoor air quality investigation that consisted of a step-by-step analysis, starting with a broad “Phase One” overview that included a review of the symptom-related documentation collected by the college’s health and safety department, a detailed visual assessment of the building and its systems, measurement of basic indoor air quality parameters, and moisture readings. An evaluation of the results of “Phase One” was followed by “Phase Two” work tasks. These included specific sampling for volatile organic compounds, airborne culturable fungi, airborne total fungal structures, and settled dust. The settled dust was characterized via optical microscopy in addition to being cultured for viable fungi. An evaluation of the “Phase Two” data revealed indicators suggesting possible sources of the indoor air quality complaints. “Phase Three” of the investigation consisted of specific targeted intrusive sampling and visual inspections of select building systems. Results of “Phase Three” confirmed the possible sources as the most likely contributors to the staff’s complaints. Findings, conclusions, and recommendations were presented, which resulted in remedial actions being conducted to correct the underlying contributing conditions and to remove and/or clean contaminated systems and materials. The library staff reported significant reductions in SBS-related symptoms after completion of the remedial activities.
B. Kollmeyer, S. Harney, Forensic Analytical, Rancho Dominguez, CA; D. Cox, D. Kahane, Forensic Analytical, Hayward, CA.
Situation: This case study involves an investigation and subsequent remediation of fungal growth in the ductwork of a large medical facility with over 20 package ventilation units.
Problem: Several challenges were encountered in the course of this investigation, including identification of the extent of fungal growth, assessment of potential exposures, and determination of causal factors. Central to the investigation was the determination of whether observed material was fungal growth or contamination. Commonly used methods of surface sampling and analysis proved unable to make this distinction, which had significant implications for remediating conditions and preventing future growth.
Resolution: In this case study, several investigative strategies were employed to develop answers to the fundamental questions regarding remediation and prevention. Considerations included type of duct lining, at risk populations within the facility, and location of ventilation units. Enhanced methods of bulk sample analysis were employed to make decisions relative to the existence of growth and surface deposition. PCR analysis was employed to assess potential exposures.
Benefit: The challenges faced and approaches employed in this investigation will help industrial hygienists to conduct more sound and complete investigations into mold growth in ventilation systems. Investigators will learn how the limits of commonly used methods of fungal growth analysis can have great implications for the optimal course of action. In addition, special considerations for medical facilities will be discussed.
R. Rottersman, G. Crawford, Boelter & Yates Inc., Park Ridge, IL.
Internal insulation is commonly used in supply air ducts. If moisture is introduced, the insulation can act as a reservoir for mold growth. The National Air Duct Cleaners Association recommends that insulation with microbial growth that cannot be restored should be removed. Removal of internal duct insulation is often cost prohibitive and impractical. Information on how to determine whether or not the insulation can be restored is limited. Mold may result from elevated relative humidity causing mold growth in the surface dust cake. A case will be reviewed that included the evaluation of fungal burden on duct insulation. The condition resulted from gaps in filters and supplemental humidification introduced into the system. Tests for culturable mold spores on the insulation surface ranged from 900,000 to >22,000,000 colony forming units per gram of dust (cfu/g). Concentrations below the insulation were as low as 3600 cfu/g, indicating that the growth may have been confined to dust on the insulation surface. A monitoring protocol was designed to measure the effectiveness of cleaning the dust from the surface of the insulation. Post-cleaning tests found mold spore levels on the insulation surface ranging from 3000 to 19,000 cfu/g, which are often considered normal background levels. Monitoring in the test area while the work was being performed identified an increase in airborne mold concentrations from 118 structures per cubic meter of air (structures/M3) to 7968 structures/M3 during cleaning activities. An increased fungal burden on surfaces in the area was also detected. The project demonstrated that, if mold growth is limited to the surface of duct insulation, cleaning may be successful at reducing concentrations to typical background levels. However, in the absence of controls, the cleaning can result in increased airborne mold concentrations in the work area and on surfaces outside the duct.
R. Morse, D. Zehnter, Morse Zehnter Associates, Poestenkill, NY.
This paper reports on testing to determine feasibility of remediating mold-contaminated fibrous glass-lined ductwork, the remediation methods used, clearance testing methods, and long-term success of the project.
Field microscopy methods were developed and confirmed by Scanning electron microscopy analysis for determining the extent and penetration of mold contamination into the duct liner. Sanitizers were tested to determine effectiveness and extent of damage to the structure of the liner materials. Field tests determined that the visible mold contamination could be removed from the surface of the liner using a HEPA-filtered vacuum cleaner. Based on these findings a remediation of the contaminated duct liner was performed using duct cleaning procedures published by the North American Insulation Manufacturer’s Association. After cleaning, the surfaces were treated with a sanitizer and clearance sampling was performed using a micro-vacuuming technique with commercially available air sampling cassettes. The interior surfaces of the liner were coated with a latex paint that contained a fungistat. Conditions in the cleaned ductwork system are being monitored to determine the long-term effectiveness of the remediation. After 24 months there has been no recurrence of mold amplification in the ductwork.
J. Krause, Indoor Air Solutions Inc., Tampa, FL.
Despite numerous cautionary statements in guidance documents from the AIHA, ACGIH, and USEPA, industrial hygienists continue to use a variety of air sampling methods to evaluate and document the effectiveness of mold remediation on surfaces. The great variability of air sampling results often leads to subjective interpretations by consultants. Some popular sampling methods used today include various types of spore traps and viable spore impactors, neither of which has been validated to be capable of demonstrating the presence or absence of fungal growth within a building. The consensus of industry and academic professionals is that the primary objective of a mold remediation project is the removal of mold growth. Any sampling method used to evaluate the efficacy of mold remediation should be able to detect mold growth and to demonstrate the absence of growth reliably and accurately. Air sampling methods currently used to estimate bioaerosol concentrations have never been demonstrated to accurately predict mold growth in a building. The commonly held belief that the ratio of indoor to outdoor mold spore concentrations ≤ 1 indicates the absence of mold growth, representing remediation efficacy, is not supported by published studies. Air sampling methods are a poor tool for post-remediation assessments because of the inordinate number of samples necessary to report meaningful results, the inability to detect mold growth on surfaces, and the turnaround time necessary to receive analysis results. The absence of detectable spores in the air cannot be interpreted as an absence of fungal growth. This presentation, using published references and field data, will describe how the use of air samples to evaluate the efficacy of a mold remediation may result in misleading conclusions and a false sense of security to building owners and occupants. Alternatives to air sampling will be presented when evaluating the efficacy of mold remediation projects.
Posted May 30, 2004