May 26, 2005
PART 3: How to respond to mold growth once it is discovered. (Or...Our building has mold; now what do we do?)
This is the third part of a three-part article that examines how mold is currently being addressed in the United States within the context of evolving standard of care issues specific to moisture-damaged buildings and mold growth. Part 3 discusses how to respond to mold growth once it is discovered. The author - Greg Baker - is a certified industrial hygienist and indoor air quality professional with over 20 years of consulting experience in buildings. Mr. Baker is an associate with AMEC Earth and Environmental in Portland, Oregon.
When mold is encountered in a building, the owner is faced with a number of complex legal, public relations, and building science issues. Before undertaking mold remediation, an owner is well-advised to take a few steps back and assess the situation. Identifying the cast of characters is an important first step, especially those responsible for the problem and those potentially involved with finding and implementing solutions to the problem. The owner should also determine the standard of care appropriate to mitigate the problem, by carefully considering business risk, the potential for future liability, and recognized industry guidelines.
Recall from Part 1 of this series of articles that "standard of care" is a legal term that refers to the quality of doing business. The concept of standard of care is: if similar industries can conduct business and make a profit maintaining that standard, then all industries should be able to maintain that same level of quality. At the end of the day, this is how the bar will be set, how the outcome of a remediation project will be judged, and how liabilities will be assumed or limited.
To determine the standard of care issues for a specific mold-impacted condition with occupancy/re-occupancy issues, and other challenging circumstances, an owner should review applicable guidance documents. At a minimum, an owner should begin with a review of the ACGIH1, EPA3, and NYCDOH4 guidelines for mold assessment and remediation. Decision-makers must appreciate that guidelines establish minimum standards of care. Parties can always choose to be more protective than the guideline recommendations, but are cautioned against being less stringent and less protective than the guidelines.
What do the mold industry guidelines consider as the "standard of care" for mold assessments and remediation projects? To begin answering this question, it is helpful to look at a few guideline examples where the standard of care recommendations are consistent. The ACGIH1, EPA3, and NYCDOH4 guidelines all state that: moisture issues must be resolved in a timely manner; mold growth and contamination must be removed; and following mold remediation, the building should be returned to a normal fungal ecology. These guidelines state that mold should not be enclosed and left behind following a remedial action, because remaining mold particles have the potential to adversely impact indoor air quality. According to these guidelines, the applications of biocides, disinfectants, and treatment coatings are not recommended, because the goal of mold remediation is to remove mold particles (dead and alive). These guidelines also state that, regardless of the type of mold and potential health implications, decision-makers must take steps to minimize or eliminate occupant and worker exposures during and after remediation and restoration activities.
By following published guidelines and the appropriate standard of care, an owner can substantially reduce risks associated with mold exposure and other mold-related liabilities. Long-term post-remediation risks can minimize future liabilities by: removing sources of contamination during the early stages of a project; eliminating major pathways of particle migration; and controlling driving forces that move particles from sources, along pathways, to receptors (people). Once implemented, these options reduce the potential for future mold exposures and indoor air quality complaints.
Removing sources of mold contamination includes eliminating visible mold growth, concealed mold growth, and reservoirs of mold particles contained in settled dusts. Why should an owner remove concealed mold and reservoirs of mold-laden settled dust from wall and ceiling spaces? Wall cavities and ceiling voids act as pathways; pathways are subject to driving forces; and pathways are almost always present in buildings (i.e., there is no such thing as an airtight building). Removing sources of mold contamination breaks one segment of the "mold exposure triangle" that consists of contaminant source, pathway, and driving forces. Remove or control any one of these three factors in the mold exposure triangle, and exposure cannot occur. Eliminating pathways and controlling driving forces are challenging prospects because: pathways are always present in buildings; driving forces may be intermittent, difficult to predict, and hard to control. Complete removal of all mold growth and contamination is not always feasible; however, removal is the most effective way and the primary way to mitigate exposures to mold contamination.
How can pathways be controlled during and after remediation? Pathways can be carefully controlled through the use of: engineering controls such as HEPA-filtered negative pressure systems; installation of temporary rigid and plastic sheet barriers; temporary modification and control of existing HVAC systems; and providing workers with proper personal protective equipment. After remediation is complete, some pathways can be sealed up permanently to restrict uncontrolled air flows, but care must be taken to avoid impairing building dynamics, and the designed performance of the building's HVAC systems.
In all cases, prudence dictates that an owner enlists the services of professionals prior to, and throughout a process of mold remediation. If building systems require modification and damaged materials need to be replaced, the owner should retain the professional services of an architect, mechanical engineer, and structural engineer. Also, the contractor that removes mold and restores the building must be an experienced mold remediation contractor, licensed, insured and bonded, with a successful track of record of similar projects, and good references.
Finally, implementation of a proactive preventative maintenance and inspection (PMI) program for mold is necessary to avoid future mold and moisture problems. Large institutions should implement a mold and moisture PMI program as a subset of a broader, proactive indoor air quality preventative maintenance and inspection program. PMI programs for mold and moisture in buildings under construction must address several specific issues that do not apply directly to existing buildings that have been in operation for years; however, there are some common PMI program elements that apply to both circumstances.
For buildings under construction, the PMI program should include training for material handling, material storage practices, installation procedures, supervision, inspections, project documenting, record keeping, and quality assurance. In the event of an unplanned water problem, the incident response team must be trained and ready to respond within hours; this is necessary to prevent mold growth and objectionable odors, and to minimize complaints and the magnitude of property damage. Existing buildings should also have a trained and appropriately equipped incident response team for the same reason. The response team can be an in-house group or a subcontracted fire and water restoration contractor. Because existing buildings are generally in use and often occupied, the PMI program for existing buildings must address tenant use issues and communications, the terms of the lease regarding maintenance responsibilities, periodic inspection protocols, record keeping, and public relations. Both PMI programs should have a single point of contact that implements and manages the program, that responds to complaints and water losses in a timely manner, and that interacts with the media when necessary.
When mold growth is encountered and the need for mold remediation becomes evident, the prudent building owner should begin with an assessment of the problem and then plan accordingly. Decision-makers should always refer to the most current guideline recommendations and consider multiple sources of guidance when contemplating remediation strategies and alternatives. Every planned corrective action should be implemented and executed in accordance with established, widely accepted guidelines and the industry standard of care, at a minimum.
Enlist the services of independent disinterested 3rd parties, including building science professionals, health and safety professionals, risk managers, and legal counsel. Use a multidisciplinary team approach to assess the scope of the mold problem, and to implement and manage corrective remedial actions.
Identify the proximate cause of the damages and the responsible parties. Those responsible for mold and moisture damage should not be allowed to simply leave behind their legacy of mold contamination - a legacy that may require long-term monitoring, management, and maintenance at additional cost to the owner - for the life of the building.
There is no practical way to remove all mold particles from indoors; the way to control indoor mold growth is to control moisture. In all cases a successful outcome to a mold remediation program depends upon three factors: resolving moisture issues; removing mold contamination; and returning the building to a normal fungal ecology.
Finally, after remediation is complete, implement an on-going preventative maintenance and incident response plan geared at managing mold and moisture for the life of the building.
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1. American Conference of Industrial Hygienists (ACGIH): Bioaerosols: Assessment and Control, edited by Janet Macher. Cincinnati, OH: ACGIH, 1999.
2. USACHPPM, Army Facilities Management Information Document on Mold Remediation Issues, TG277, February 2002.
3. U.S. Environmental Protection Agency. Mold Remediation in Schools and Commercial Buildings, EPA 402-K-01-001, March 2001.
4. New York City Department of Health: Guidelines on Assessment and Remediation of Fungi in Indoor Environments. New York: New York City Department of Health, Bureau of Environmental & Occupational Disease Epidemiology, (April 2000), January 2002.
5. The American Industrial Hygiene Association (AIHA) Guideline 3 - 2004, for Assessment, Remediation, and Post-Remediation Verification of Mold in Buildings, IAQG 04-659; AIHA, 2004; www.aiha.org/webapps/commerce.
6. American College of Environmental and Occupational Medicine (ACEOM), Policies and Position Statements, Evidence Based Statements; Adverse Human Health Effects Associated with Molds in the Indoor Environment; ACOEM, 2000; www.acoem.org