I Think It's Mold! (Now What?)
- By Alfred C. Draper III
- May 01, 2005
What kind of risks does mold growth pose to an organization? How should those risks be assessed?
"I don't see what the big deal is. It's just a little mold."
"Oh, no! We have mold problems. This is bad, real bad."
Which of those two reactions is appropriate, given the risks associated with mold and the context of the various challenges industrial hygienists and occupational health professionals deal with every day? The answer, for those of us who pride ourselves on good science, risk assessment, and safety and health programs, is "Neither of the above." The answer can be found in having a complete understanding of mold causes and risks, assessing the specific risks, and responding in a timely, efficient manner.
Understanding the Risks
So just how hazardous is mold, and what are the real risks to a facility and its occupants? Here's what we know: Mold is naturally occurring fungi that can thrive wherever moisture is present, especially in combination with poor ventilation and humidity above 60 percent. As an allergen, mold can be particularly troublesome for the elderly, the very young, and those whose immune systems are already compromised by illness or disease. In general, mold should be of greatest concern in schools, day care centers, nursing homes, hospitals, and apartment buildings. According to a 2002 study, as many as one-fourth of all occupational asthma cases may be related to exposure to mold or mold spores.
The hype about mold peaked during the late 1990s. It helped to focus attention on the issue but also scared people unnecessarily. Fears about "toxic" mold and "black" mold may have been good for business, but there is little value in talking about "toxic" mold because that implies there is "non-toxic," health effects-free mold. The reality is that the impact of mold is generally believed to be dose-related: The more exposure you have, the greater the potential health effects--although the dose-response relationship is not well-established and there can be wide variations in people's symptoms.
In our experience as a large environmental contractor, the bottom line on the health effects of mold is this: Mold can be a significant health hazard, especially to sensitive populations, and any risk assessment and corrective action must take into account the severity of the problem and the impact on workers, residents, and visitors.
Other Reasons to Respect Mold
However, health impact should be only part of the equation in understanding the risks and the importance of risk assessment and corrective action. Other reasons to respect the mold include the structural integrity of buildings, aesthetics, insurance premiums, and resale value. Mold is a parasitic saprophyte, which means it cannot manufacture its own food; instead, it derives its nutrients from the materials on which it is growing. As a result, mold is capable of causing significant structural damage to buildings.
Given the health and non-health risks, mold deserves the attention of industrial hygienists, occupational health professionals, and facility managers. This is no time to panic, however.
Sources of Moisture and Mold
Mold can be found almost anywhere; it can grow on virtually any substance, wherever moisture is present. Where mold is a concern, it must be cleaned up and moisture sources eliminated and ventilation improved, or the problem will get worse. Naturally occurring hazardous materials do not correct themselves over time; they feed off existing conditions unless there is appropriate intervention.
Moisture can enter and spread throughout a facility through various sources, both internal and external. A thorough understanding of these sources can help organizations identify the best prevention and control measures. Leaks are the most common source of moisture in facilities and can be found in pipes, roofs, and ceilings and around walls, windows, or doors. A leak can be an entry point for moisture through internal (pipes) or external (rain) sources.
Internal sources of moisture can appear to be so routine and mundane that the resulting mold may go unrecognized and grow insidiously for years. Sometimes, the introduction of external moisture sources accelerates mold growth and exposes long- and short-term problems.
During new construction and renovation, contractors should consider moisture when prioritizing their tasks. Buildings should be thought of as integrated systems, not individual components. Failure to appreciate this reality often manifests itself in the form of construction defects. If the water-shedding ability of a structure is inadequately designed or constructed, for example, there is no hope for a dry facility. Other typical design and construction defects include mold growth between walls, where the roof meets the walls, around windows and skylights, and when contractors do not allow concrete and wallboard joints to dry completely before applying finishing materials.
This article originally appeared in the May 2005 issue of Occupational Health & Safety.