Mold: The Ubiquitous Invader

Mar 4, 2000 by

by Avery Reed, REA

What is the largest living thing? Is it a sperm whale or a giant sequoia tree? Neither. We can not identify the source, but it is a reported legend amongst little known environmental assessors that a single spore from a fungi was found growing in the jungles of Brazil to a size taller than a five-story building and longer than a football field, and it is still growing. One species of poria fungi, commonly called dryrot, was reported in the Orange County Register to have destroyed an entire house on Balboa Island, eating the walls from the inside out! One of the largest insurance companies in America abandoned the homeowner’s insurance market in the state of Texas, leaving 600,000 clients behind, after losing a class action mold lawsuit exceeding 30 million dollars.

I was asked for an article about mold and along the way, to answer a few of the primary questions that are asked by homeowners, risk managers, building owners, developers, insurance adjusters and attorneys. What is mold? What are we looking for? How dangerous is it? How do we look for it?

After conducting hundreds of field assignments related to mold and reviewing a similar number of reports written by other indoor air quality investigators, one word is repeated over and over again to describe mold: Ubiquitous. It is one of those ten-dollar words that “tell it like it is.” Mold is everywhere, omnipresent, being without end, the natural blight. It is found between a “rock and a hard place”. It ages our cheese, it creates our antibiotics and it consumes cellulose in wood, human tissue, gasoline, complex hydrocarbons (many we call collectively, methyl-ethyl-double death), along with some metal elements.

It consists of components of biological origin that we call biogenic particles, living or dead. Certain species of mold reinvents itself when threatened–by producing deadly mycotoxins, secondary metabolites–when competing for food, growing space or survival. Several of these mycotoxins, most with complicated names, create chemicals that are known to be carcinogens. Satratoxin H, produced by Stachybotrys, is lethal in high doses as well as chronic low doses. Mold is known to be many things, but it is certainly ubiquitous.

With the exception of legionnaires, which is a bacteriological pathogenic disease found in buildings, biogenic particles with insect parts, skin fragments, fibers and pollen are a primary cause of illness in buildings, and often responsible for what we commonly call the Sick Building Syndrome. Fungal spores and fragments are inherent to the cause of asthma, allergies and hypersensitivity pneumonitis in certain individuals exposed in their homes or offices to moderate levels over long periods. Scientific research and study has been slowly evolving, until recently, because allergists and medical health practitioners interview patients, take blood samples, prick skin and take tissue samples over months and years. This doctor-patient analysis is often confidential, without written reports; whereas environmental assessors experienced with microorganisms in indoor air quality are technically-trained persons in mold abatement who evaluate buildings and conduct field-mold investigations to determine the quantity and quality of biogenic particles and eradicate mold at it’s source. Short-term exposure to high airborne concentrations of certain species of fungi, particularly by children, the elderly, asthmatic individuals and those with compromised immune systems, can cause chronic illness. We have found that long-term exposure to low and moderate levels of fungi may produce the same result. At one site, fungi spores were found in the blood of a sensitive worker in a modern building exposed to a moderate concentration of a particularly virulent mold genus. In a residential site, the surgeon removed fungal balls from the inside of the lung of a patient who later paid an environmental site assessor and contractor over $25,000 to design and complete the remediation of mold originating from a leak under the kitchen sink.

What is the first step? Determine the location of the work. Aside from special work environments such as bacteriological laboratories, wastewater treatment plants, food processing plants, oil refineries and clean-rooms, these tasks are generally first outlined with the client for a specific contract:

· Identify the type of site: Residential, commercial, industrial, manufacturing, hospital, school, public building or hazardous-work in progress. · Discuss the problem and the anticipated scope of work with the client.

· Create an order of magnitude budget and schedule to perform the work.

· Define resources; create a decision tree or logic diagram for the site (larger work).

· Determine analytical techniques proposed and schedule laboratory time.

· Upon determination of the presence or absence of hazardous levels of fungal organisms, be prepared to report findings in a format acceptable to the client for the purpose intended.

A definitive description of proper sampling procedures and evidence protocols is beyond the scope of our writing assignment. On projects requiring rapid results, where viable and non-viable indoor air quality determination by the microscopy-analytical-laboratory method is required, we use one or a combination of bulk, tape and Air-O-Cell samples. Special attachments may be used to collect samples from the inside of walls, wall surfaces, wood floor, carpet, concrete and soil. The number of samples collected is based on the client’s needs, verification of conclusions reached by prior environmental professionals and a judgment based on practical experience. At one site, a mold had so infested the wall behind the bedroom dresser that a book that had fallen behind the dresser was covered with Aspergillus mold, with spores in full bloom. The bulk sample taken in the bedroom of that residence was the entire book!

At sites requiring a definitive analysis of the mold, we use a specialized instrument called an impactor, with an electric motor driven vacuum pump. We calibrate the device to draw a known volume of air over a selected time interval, into a precisely made metal chamber containing a dish with an extract of a substance that mold recognizes as food. In most cases, this food is potato agar extract. Samples are entered on a laboratory Chain of Custody, removed from the sampling device, sealed, labeled, packaged in the appropriate container and shipped to the microbiology laboratory on blue ice. The laboratory samples are cultured in an incubator for at least five to seven days, at which time they are removed. The microbiologist views the growth under a microscope and–based upon experience, comparison of color, growth characteristics and fungal structure–identifies the various molds in the incubated dish by species and genera. Other methods of collecting samples of mold are useful, such as the use of a sterile swab, for laboratory incubation and later identification. In this manner, the environmental assessor collects samples, obtains laboratory results, interprets those results and reports findings to a client.

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