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Here we list reasons to test for the presence of mold or to collect samples to identify the kind of mold present in buildings. We emphasize that for small areas of mold contamination, generally where less than 30 square feet of contiguous mold is present, simple building cleaning and renovation procedures are all that's needed and testing is usually not appropriate. Most building mold contamination falls in this first category. At DO IT YOURSELF MOLD CLEANUP we provide suggestions for a do-it-yourself cleanup of small areas of mold. At MOLD EXPERT, WHEN TO HIRE we provide guidelines to help decide when it is probably justified to bring in a mold expert to perform mold inspection and testing in a building.

In this article series we discuss the validity of nearly all of the popular mold testing methods currently in use, pointing out the strengths and weakness of each approach to mold sampling in the indoor environment, beginning with air sampling for airborne mold levels indoors. The appropriateness of testing at all is discussed on this and other pages at our website. Because mold test validity and mold test accuracy are often confused, readers should also see ACCURACY OF VARIOUS MOLD TEST METHODS. People who need to conduct mold inspection and testing indoors should see MOLD TEST PROCEDURES and TECHNICAL & LAB PROCEDURES.

© Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

This discussion is divided into two main topics:

1. Mold "Testing" vs. Mold "Problem Identification" - what is the difference between "mold testing" and "mold identification", and what good are consumer mold test kits.
2. Reasons to Test for or Identify Mold - three reasons why in some conditions it is appropriate, useful, cost justified to test for mold and to identify the kinds of mold that are present.

Our MOLD INFORMATION CENTER includes more broad discussions of the overall approach to building investigation, as do many expert references cited at that web. For a more comprehensive collection information about mold test methods see INDOOR AIR QUALITY METHODS COMPARED. For more on "mold classes" (Cosmetic mold vs. allergenic mold vs. toxic or pathogenic mold) see MOLD CLASSES, HAZARD LEVELS and more references such as a Mold Action Guide are at the end of this document.

When is it Useful to Test for & Identify Mold in Buildings?

15th Annual North Carolina/South Carolina
Environmental Information Association Technical Conference
Myrtle Beach, SC
Daniel Friedman 23 September 2005

© Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

1.  Save Money if it's Just Cosmetic Mold
2.  Mold Related Illness
3.  Mold Cleanup Data baseline

Why try to identify mold at all. Some practitioners argue that no testing is needed, mold should simply be found and cleaned-up. We agree with this approach for small areas of mold where there are no larger issues such as occupant complaints or BRE (building related illness).

Why identify mold - Reason 1: Cosmetic-only vs. problematic mold

But if mold present in the building is only of "cosmetic" concern, it is unlikely that special cleanup methods such as negative air, establishment of a containment system, and special personal protection for workers is needed. If these special methods can be avoided, the cost to remove mold will be substantially less. Therefore it cases where a large amount of mold is present it may be appropriate to have an expert perform testing and to prepare an appropriate remediation plan to guide the remediation contractor. The same expert may be used to perform clearance testing later to assure that the cleanup was proper and successful. Also see Can mold make you sick?"

Harmless "Black Mold": A very common example is the Ceratocystis/Ophistoma group which appear as "black mold" on framing lumber and which are more commonly known as "blue stain" or sapstain molds. This mold is found on lumber as it arrives from the lumber yard - a condition that is readily apparent to a building expert and which can be confirmed by sample identification.

Allergenic mold: Other dark molds, including the most common genera Cladosporium sp. are often allergenic: a potential respiratory irritant or a problem for people with allergies, asthma, or other sensitivities.

Toxic/Pathogenic mold: a third broad group are molds which we call "toxic" and includes species which are toxic, pathogens, or infectious agents which in some cases may be capable of infecting humans or of producing disease in humans. Aspergillus flavus, A. niger, are two examples.

We find in many cases that large areas of "black mold," about which owners/occupants may be unduly frightened, are Ceratocystis/Ophistoma, a common mold that is found on framing lumber from time of construction, and which is known to be only of cosmetic concern, and which is not an indicator of mold-conducive conditions in the building - it came in on the lumber and is inactive and cosmetic.

Without knowing what this is, people may make large and inappropriate expenditure on "professional remediation" - in one case in CT a client was about to launch a $600,000. complete re-framing of the first floor of a building, a totally inappropriate step which was completely unnecessary with a little knowledge of mycology and building science.

Ambiguous airborne mold counts: A second example of this sort is the need to distinguish between two "mold counts" that appear to be the same but actually mean very different things. An outdoor 500 Pen/Asp spores/M³ of air and an apparently low indoor 400 Pen/Asp spores/M³ may take on a new meaning if the outdoor spores are a different genera/species than the indoor ones.

Why identify mold - Reason 2: convey possible health effects to a physician

Proving that mold in a building caused a health concern is so arduous and costly as to be inappropriate in most cases. If a lot of allergenic or toxic mold is present, it needs to be removed. But information about what was found in a building may be useful: a number of our clients have health complaints for which IAQ problems are a potential cause or contributor - information which they want to convey to their physician.

For example, a delay in diagnosing fungal infections in two of our clients led each to have permanent loss of eyesight. We acknowledge that these cases are not common, but they occur enough for caution to be in order. We don't submit that we should be practicing medicine nor diagnosing ailments, rather that information about a sick person's environment might be useful to their physician.

Dr. Harriet Burge (ret) at the Harvard School of Public Health has taught me that the cost of proving that a specific illness is caused by a specific mold or allergen in a particular environment is so arduous as to be impractical. However we agree, as we expect you do too, that if a large area of allergenic or more toxic mold is present in an environment it should be removed.

Can Mold Make You Sick?

We live in a sea of mold, and other stuff in the air we breathe, on cushions we sit on, clothes we wear, pools we swim-in, and so on. Most mold is not hurting anyone, and some of it makes us well when we're sick(Penicillium notatum, for example). Fear of mold (mycophobia) is unjustified and in our opinion, more a result of media hype, enviroscare, and gouging consumers.

A healthy person walking through a room of moldy air is not likely to die. On the other hand, there is a wealth of less rigorous empirical data matching occupant complaints with indoor mold and allergens. Finally, for certain people, mold can be a serious problem if it's at high levels indoors. It's probably an overstatement by those authorities who assert that "... there are no proven links between mold and illness." we refer readers to some of our lab's references for descriptions of illness-related molds, some of which are found in buildings:

1. Identifying Filamentous Fungi , A Clinical Laboratory Handbook, Guy St-Germain, Richard Summerbell, Star Publishing, 1996, ISBN 0-89863-177-7
2. Fundamentals of Diagnostic Mycology, F. Fisher, N.Cook, W.B. Saunders, 1998, ISBN 0-7216-5006-6
3. Atlas of Clinical Fungi , 2nd Ed., G.S. de Hoog, J. Guarro, J. Gene & M.J. Figueras, Centraalbureau voor Schimmelcultures, Utrecht, The Netherlands, 2000 ISBN 90-70351-43-9.
4. InspectAPedia.com/sickhouse/bibliog.htm contains a more extensive reference list of mold investigation, mold lab procedures, and health references.

Why Identify mold - Reason 3: establish a data baseline and later, evaluate the success of a professional mold remediation project

See MOLD EXPERT, WHEN TO HIRE for a discussion of when it is or is not appropriate, justified, and ethical to hire a mold consultant to inspect, diagnose, and advise about mold contamination in a building.

Where large areas of mold remediation are needed, using professional cleaning services, we find that in many cases the "professional" does not properly maintain containment, and actually increases the level of allergens in the building. In buildings where occupants are at particular risk (elderly, immune-impaired, infant, asthmatic) we have had cases where an occupant entered an area contaminated with high levels of allergenic mold and suffer severe asthma attacks. In Ellenville, NY at a private residence we learned of a fatality involving just such an incident.

For large remediation projects we find it very useful to have a base-line of data on what areas need to be cleaned and which are acceptably clean before the remediation project. Then a quick test after the remediation can confirm not only that it was successful, but that the remediator did not inadvertently fail to contain.

If the containment was unsuccessful and other building areas have become contaminated enough to want to have additional cleaning (typically HEPA vacuuming or wiping), having the baseline showing that the contamination followed the remediation rather than preceded it protects the property owner or occupant from additional unnecessary expense.

The usefulness of samples depends on the knowledge and thoroughness of the person collecting the sample as part of a building investigation. Arbitrary or random samples are unlikely to be a reliable characterization of a building. Choice of method as well as how the method is applied (for example, just where to stick the tape to collect a surface sample) makes a large difference in the quality and representativeness of the sample.

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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

MOLD TESTING METHOD VALIDITY
Introduction
  Air samples
    Shortcomings of air sampling
    Mold in Air: Quantitative Analysis
  Tape sampling for mold
    Determination of mold genera
    Determination of mold species
    Shortcomings of tape sampling
  Vacuum samples
    Surface vacuuming
    Shortcomings of surface and carpet vacuuming
    Vacuuming building cavities
    Vacuuming exposed insulation
    Shortcomings of vacuuming insulation
  Cultures to "Test for Mold"
    Shortcomings of culturing
  Swab sampling
  Shortcomings of swab sampling
  PCR methods for Mold Identification
  Mold "Testing" vs. Mold "Problem Identification"
  Are Mold Test Kits Useful?
  Reasons to Test for or Identify Mold
    1. Save Money if it's Just Cosmetic Mold
    2. Mold Related Illness
    3. Mold Cleanup Data baseline

• Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. (727) 595-4211 mark@BestTampaInspector.com
• Craig Balchunas is an ASHI member, and a licensed New York home inspector and environmental and mold test inspector in Newburgh, NY.

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