Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
ENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY
MOLD: A COMPLETE GUIDE to TEST CLEAN PREVENT
ACCEPTABLE MOLD LEVEL
ACCURACY OF VARIOUS MOLD TEST METHODS
ACCURACY vs PRECISION of MEASUREMENTS
ACTION GUIDE - WHAT TO DO ABOUT INDOOR MOLD
ACTIVITY of MOLD in BUILDINGS
AGE of MOLD - Old is the Mold?
AIR CLEANER PURIFIER TYPES
AIR FILTERS for HVAC SYSTEMS
AIR POLLUTANTS, COMMON INDOOR
AIR TEST FOR MOLD: ACCURACY
AIR TEST SAMPLING CASSETTE STUDY
AIRBORNE MOLD COUNT NUMBER GUIDE
AIRBORNE PARTICLE ANALYSIS METHODS
ALLERGEN TESTS for BUILDINGS
ALLERGENS in BUILDINGS, RECOGNIZING
ALLERGY & MOLD IAQ PRODUCTS
ALLERGY TESTS for PEOPLE
ALLERGY TEST ACCURACY
ATTORNEYS and EXPERT WITNESSES
BASEMENT MOLD WATER IMPACT
BROWN HAIRY BATHROOM MOLD
BIBLIOGAPHY for ENVIRONMENTAL HEALTH, MOLD, IAQ
BOD WASTEWATER TEST
BLACK MOLD, HARMLESS COSMETIC
BLACK MOLD, TOXIC & ALLERGENIC
BLEACHING MOLD, Advice about
BLUE vs YELLOW COMBUSTION FLAMES
BOOK MOLD, Moldy Book Cleaning
BOOKSTORE - ENVIRONMENTAL
CACTUS FUNGI / MOLD
CAR MOLD CONTAMINATION
CARPET DUST IDENTIFICATION
CARPET MOLD CONTAMINATION
CARPET PADDING ASBESTOS, MOLD, ODORS
CARPET FUNGICIDAL SPRAY
CARPET STAIN DIAGNOSIS
CARPET & other STAIN TESTS
CARPET TEST PROCEDURE
CARPETING & INDOOR AIR QUALITY
CHAIN OF CUSTODY - TEST SAMPLE
CLEARANCE INSPECTIONS - MOLD CLEANUP
DIRECTORY of MOLD / ENVIRONMENTAL EXPERTS
DIRT FLOOR MOLD CONTAMINATION
DISINFECTANTS & SANITIZERS, SOURCES
DISINFECTING BUILDINGS with BLEACH
DO-IT-YOURSELF MOLD CLEANUP WARNINGS
DRYWALL MOLD TESTING
DUCT SYSTEM & DUCT DEFECTS
DUST ANALYSIS for FIBERGLASS
DUST, HVAC CONTAMINATION STUDY
DUST SAMPLING PROCEDURE
EFFLORESCENCE, Salts & White / Brown Deposits
EMERGENCY RESPONSE, IAQ, GAS, MOLD
FEAR of MOLD - MYCOPHOBIA
Fiberboard Insulation Sheathing Mold
FIBERGLASS INSULATION MOLD
FIBERGLASS PARTICLE CONTAMINATION TEST
FIELD INVESTIGATION SERVICE
FIND MOLD, ESSENTIAL STEPS
MOLD in BUILDINGS
FIRE DAMAGE vs MOLD DAMAGE
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOODS IN BUILDINGS-mold
FLOORING MATERIALS, Age, Types
FOXING STAINS on books & papers
FUNGICIDAL SPRAY & SEALANT USE GUIDE
GAS DETECTION INSTRUMENTS
GAS EXPOSURE EFFECTS, TOXIC
GAS EXPOSURE LIMITS & STANDARDS
GAS TEST PROCEDURES
HOUSE DUST ANALYSIS
HOUSE DUST COMPONENTS
HOUSEWRAP AIR & VAPOR BARRIERS
HIDDEN MOLD, HOW TO FIND
HUMIDITY CONTROL & TARGETS INDOORS
INDOOR AIR HAZARDS TABLE
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
LAB PROCEDURES MICROSCOPE TECHNIQUES
LEAD POISONING HAZARDS GUIDE
Legionella Legionnaires' Disease
Legionella BACTERIA & HVAC Equipment
LIGHT, GUIDE to FORENSIC USE
GAS LP & NATURAL GAS SAFETY HAZARDS
MEDIA BLASTING for MOLD REMOVAL
METHANE GAS SOURCES
MICROSCOPE DIGITAL PHOTOGRAPHY
MEDIA BLASTING for MOLD REMOVAL
METHANE GAS SOURCES
MICROSCOPE DIGITAL PHOTOGRAPHY
MILDEW in BUILDINGS ?
MILDEW ERRORS, IT's MOLD
MILDEW REMOVAL & PREVENTION
MOISTURE CONTROL in BUILDINGS
MOLD: A COMPLETE GUIDE TO MOLD
MOLD ACTION GUIDE - WHAT TO DO ABOUT MOLD
MOLD APPEARANCE - WHAT MOLD LOOKS LIKE
MOLD CLEANERS - WHAT TO USE
MOLD CLEANUP GUIDE- HOW TO GET RID OF MOLD
MOLD CLEARANCE INSPECTIONS
MOLD COUNT NUMBER GUIDE
MOLD CONSULTANTS / INSPECTORS
MOLD CULTURE TEST KIT VALIDITY
MOLD DETECTION & INSPECTION GUIDE
MOLD or INDOOR AIR EMERGENCY RESPONSE
MOLD EXPERT, WHEN TO HIRE
MOLD LEVEL IN AIR, VALIDITY
MOLD ODORS, MUSTY SMELLS
MOLD PREVENTION GUIDE
MOLD RELATED ILLNESS GUIDE
MOLD SAFETY WARNINGS
MOLD SPRAYS, SEALANTS, PAINTS
MOLD TEST KITS
MOLD TESTING METHOD VALIDITY
MSDS Material Safety Data Sheets
MVOCs & MOLDY MUSTY ODORS
MYCOPHOBIA, STAINS MISTAKEN for MOLD
MYCOTOXIN EFFECTS of MOLD EXPOSURE
NOISE / SOUND DIAGNOSIS & CURE
ODORS GASES SMELLS, DIAGNOSIS & CURE
OZONE for MOLD OR ODORS
PAINTS & COATINGS ODORS IN BUILDINGS
PARTICLE SIZES & IAQ
Particulates & Allergens Indoors
PESTICIDE EXPOSURE HAZARDS
PET ALLERGEN REMEDIES
PLASTIC CONTAINERS, TANKS, TYPES
PLASTIC Plexvent / Ultravent RECALL
PLASTIC ODORS-SCREENS, SIDING
PLUMBING SYSTEM ODORS
RENTERS GUIDE TO MOLD & IAQ
ROBIGUS & Wheat Rust Fungus
ROT RESISTANT LUMBER
ROT, TIMBER FRAME
ROT, TIMBER ASSESSMENT
SLIDE PREPARATION, MICROSCOPE
SMELL PATCH TEST to Track Down Odors
SOUND CONTROL in BUILDINGS
STAIN & BIODETERIORATION AGENT CATALOG
STAINS on & in BUILDINGS, CAUSES & CURES
STAIN DIAGNOSIS on BUILDING EXTERIORS
STAIN DIAGNOSIS on BUILDING INTERIORS
STAINS on INDOOR SURFACES: PHOTO GUIDE
STAINS & Thermal Tracking
TECHNICAL & LAB PROCEDURES
TEST KITS for DUST, MOLD, PARTICLE TESTS
Thermal Expansion Cracking of Brick
THERMAL EXPANSION of HOT WATER
THERMAL EXPANSION of MATERIALS
THERMAL IMAGING, THERMOGRAPHY
THERMAL IMAGING MOLD SCANS
THERMAL MASS in BUILDINGS
THERMAL TRACKING & THERMAL BRIDGING
TRAPPED MOLD BETWEEN WOOD SURFACES
TRIM, INTERIOR INSTALLATION
TRUSS UPLIFT, ROOF
TRUSSES, Floor & Roof
UREA FORMALDEHYDE FOAM INSULATION, UFFI
URETHANE FOAM Deterioration, Outgassing
UV LIGHT BLACK LIGHT USES
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VENTILATION in BUILDINGS
VINYL CHLORIDE HEALTH INFO
VINYL Siding or Window PLASTIC ODORS
VOCs VOLATILE ORGANIC COMPOUNDS
WALL SIDING TRIM & FINISHES
WALL FINISHES INTERIOR
WALL CONSTRUCTION BARRIER vs CAVITY
WATER BARRIERS, EXTERIOR BUILDING
WATER ENTRY in buildings
WATER ODORS, CAUSE CURE
Mold Standards for Exposure & Testing: this InspectAPedia technical article describes various current & proposed mold standards as well as the very substantial shortcomings in any mold exposure standard whatsoever. Here we also explain reasons for substantial variation in and interpretation of the meaning of airborne mold spore counts, moldy surface density, and other measures of the exposure level of allergenic, infectious, and levels of toxic mold in buildings. At what level is allergenic or toxic mold considered a problem in buildings? How do we obtain an accurate and meaningful measurement of mold exposure indoors?
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
Readers should see MOLD RELATED ILLNESS GUIDE, and MOLD RELATED ILLNESS SYMPTOMS and MOLD EXPOSURE STANDARDS and also see MOLD RELATED ILLNESS GUIDE, see MOLD EXPOSURE, FOOD HAZARDS, and MOLD RELATED ILLNESS SYMPTOMS and ACCEPTABLE MOLD LEVEL. For background on how and why molds can be toxic, see this World Health Organization Mold Bulletin.
Warning: fungal spore counts in indoor air, whether "viable" or "non-viable" counts, as well as swab and culture methods to identify just what mold is present in a building are questionable methods to characterize the presence or absence of a mold problem indoors.
From experience carefully inspecting many buildings for mold problems and simultaneously collecting many types of field samples and examining them in our lab, our view is that anyone who makes one or a few indoor air measurements or relies on culture plates or swabs to "characterize" the mold level and mold species in a building is risking being way off target, particularly if the "test results" show low numbers.
See ACCURACY OF AIRBORNE MOLD SPORE COUNTS for more details about these issues. That said, here is a sampling of some indoor air mold spore exposure level criteria and comments
1. Baxter et als: Mold contamination is considered present in a building when the total mold spore concentration per cubic meter is above 10,000. Our own field and lab experience confirms this view. However in special cases, even low quantitative levels of certain particles or particle types (such as Pen/Asp spore chains in an un-treated building) may be diagnostic and may indicate a hidden mold reservoir that at least merits further investigation.
2. The National Allergy Bureau, reporting the NAB SCALE (National Allergy Bureau) of mold and pollen counts, considers mold counts in outdoor air of 0-6499 spores per cubic meter of air as low, to 6500 to 12,999 spores per cubic meter of air as moderate, to 13,000 to 49,999 spores per cubic meter of air as high, and above 50,000 as very high. At "high" levels most individuals with any sensitivity will experience
symptoms. AAAAI also provides absent, low, moderate, high, and very-high level level definitions for grass, tree, and weed pollen grains counted per cubic meter of outdoor air.
3. The University of Minnesota data presents this table for mold levels expressed in colony forming units per gram. WARNING: mold spores may be not viable (dead), wrong culture media may be used, or one species can overgrow another, etc. - so don't produce any colonies, but may be toxic if inhaled (such as some species of Penicillium). So we would not rely on culture data. But here it is:
Colony Forming Units/gram - cultured mold samples as indicators of mold level in buildings
WARNING: about interpreting mold cultures: this is a very very inaccurate method for screening buildings for the level of mold contamination for many reasons, including that only 10% of all molds will grow on any culture under any condition. So this approach begins as 90% "wrong".
Other mold level variables include the differences in settlement rate out of air as a function of particle size and weight, proximity to a mold contamination reservoir, and the problem that a serious toxic mold may be overgrown (if it grows at all) in the culture by a second mold species which hides the first one. See INDOOR AIR QUALITY METHODS COMPARED for details of these issues.
4.The American Conference of Government Industrial Hygienists (ACGIH) stated (Harriet Burge et. al) stated in 1987 that indoor mold levels are generally less than 1/3 the outdoor level and that when indoor mold is at more than this level remedial action should betaken to find the source of the elevated counts and to clean it up.
WARNING: this is an inaccurate and unreliable method for screening buildings for mold for many reasons, including:
See INDOOR AIR QUALITY METHODS COMPARED for details of these issues.
5. Other proposals for Mold Exposure Standards have included a limit of 500 CFU/ of mold spores per cubic meter of air in winter indoors in sub arctic climates (Reponen et al.1990). CFU means "colony forming units" of mold.
At MOLD CULTURE PLATE TEST ERRORS we have cited the range of errors and limitations of using cultures to check for viable mold, and we point out that depending on the particular mold genera and species present in a building, even non-viable mold may be allergenic or toxic. That is why experts in mold testing and remediation advise that the object is to remove mold or clean up mold in a moldy indoor environment, rather than attempting to "kill" mold indoors.
Also see INDOOR AIR QUALITY METHODS COMPARED for details of these issues.
Single number "mold levels" are very unreliable as a measure of health risk in buildings for several reasons including at least the following:
Particle levels vary widely over short time periods: The actual level of indoor particles in air varies by several orders of magnitude over very short few-minute intervals, making reliance on any single measurement questionable, particularly if the measurement does not show evidence of a problem.
The absolute level of airborne particles in buildings varies enormously, possibly by a factor of hundreds to thousands, over intervals as short as a few minutes. Simple mechanical disturbance like turning on or off a fan can completely change individual measurement results. Short term measurements are therefore inaccurate and even longer term measurements are inaccurate if they do not consider the in-use variations in dust disturbance in a building.
Human sensitivity to mold varies: Individual susceptibility to mold/mycotoxin/aflatoxin-related or allergy-related illness varies widely and human exposure is complex because people move among a variety of environments
Finally, because of wide variation in individual human reaction and risk to mold, variation in allergenicity, pathogenicity, and toxicity among mold genera and individual species, and even additional variation in these levels depending on specific environmental conditions such as the substrate upon which a mold is growing (its food), quantitative risk-levels are better used as an overall indication of building cleanliness before and after a mold cleanup, and not as an absolute level of risk to building occupants.
There is very wide variance among the toxicity of individual mold species, ranging from none to probably highly toxic, pathogenic, or even carcinogenic
Mold Spore size varies widely from less than 1 u to over 200u, so a large spore contains potentially more harmful material than a small spore of the same "toxicity," making a "count" that does not identify the particle and particle size ambiguous
Mold spore toxicity may vary, even within an individual species, depending on what substrate the species is growing on in a particular instance, e.g. wood vs. drywall.
These mold spores vary in significance: procedures that use cultures to identify "viable" spores may omit high levels of non-viable spores which nonetheless remain highly toxic. Methods that rely on culturing have a high risk of identifying a mold which is present but is not the dominant or even the most problematic mold in the building. For more details see Mold Spore Counts: are indoor fungal spore counts valid?for further explanation.
For the standards and references below, numbers are spores per cubic meter of air and do not consider individual or viable/non-viable or genera-species specific levels. There is a serious limitation of the standards since the spores of different genera and species vary widely in total size, mass, and toxicity.
The level of airborne particles indoors varies enormously, by orders of magnitude, from moment to moment, making the strict interpretation of any "indoor air mold test" unreliable, as we discuss at ACCURACY OF AIRBORNE MOLD SPORE COUNTS. -DF
Note: Previous data provided at this web article had been obtained from a presentation by J.R. Tucker, EMS-sales, who presented data at the NC/SC Environmental Information Association 2005 Conference, Myrtle Beach, SC citing mold exposure standards from Brazil, mold exposure standards for Czechoslovakia, Mold exposure guidelines for Finland, Mold exposure standards set by the Nordic Council, mold standards cited by the World Health Organization WHO, and mold exposure standards for the Netherlands and lastly, mold exposure standards for Poland. Those figures were quoted in this article from the material provided at that conference. Mold exposure standard numbers were expressed spores per cubic meter of air and did not consider individual or viable/non-viable or genera-species specific levels. We have removed those data points at the request of Dr. Robert Brandys who informed us that he was and remains the original author.
Mycotoxins are produced by some common molds found in buildings, including Aspergillus, Penicillium, Fusarium, Stachybotrys, and even Alternaria. Common classification groups of mycotoxins include aflatoxins, fumonisins, trichothecens, and ergot alkaloids. Arora has pointed out that the following conditions are necessary for mycotoxins to affect humans:
Human Health Complaints on Exposure to Problematic Mold, possibly including Mycotoxins
Given even these stringent criteria, field investigations of moldy buildings that we have conducted from 1986 to present, included both human building occupants and in some cases pets who appeared exhibit complaints or symptoms consistent with mycotoxin exposure. Some of these clients and their physicians confirmed that exposure by appropriate medical tests.
Sheep Circling Disease and Toxic Mold Exposure
A fellow aerobiologist who also has experience raising sheep, Larry Syzdek (PAAA member) informed us of a mold-related illness well known to occur in sheep which Syzdek explained has occurred in his experience in sheep exposed to moldy straw, called in lay terms, "sheep circling disease" (Listeriosis, however Listeria moncytogenes is the specific bacterium - not a mold - known to cause listeriosis, a disease which can affect both other animals and also humans, particularly pregnant women who are 20 times more likely than other healthy adults to get listeriosis).
The author of this web article, (Friedman) has described field observations of dogs appearing to exhibit strange behavior (running in circles, falling down, disorientation, and occasional uncharacteristic aggressive behavior, and in one case, fatal internal bleeding after severe exposure to S. chartarum during a building demolition. These animals were pets of clients whose homes were severely mold-contaminated. With Syzdek, we have speculated on the possibility that other animals than sheep may be similar affected by exposure to some indoor molds and may be exhibiting behavior similar to that caused by Listgeriosis though the etiology of this disease is suspected to be different.
These hypothetical remarks presented here intend to solicit additional field reports and data, possibly in support of future controlled studies. Readers should not assume that we have drawn conclusions from the suggestive anecdotal data currently at hand.
Some species specific acceptable levels have been addressed and vary considerably by species, environmental conditions, and proponent.
REFERENCE:A number of resources cited here are reviewed more carefully in "Comparisons of seasonal fungal prevalence in indoor and outdoor air and in house dusts of dwellings in one Northeast American County," Ping Ren,
Thomas M. Jaunkun and Brian P. Leaderer, Division of Environmental Health Sciences, Department of Epidemiology and Public Health, Yale University School
of Medicine, New Haven Ct. and appearing in the Journal of Exposure Analysis and Environmental Epidemiology (1999) 9, 560-568.
See references below for important additional information such as mold testing, cleanup and mold remediation guideline resources.
According to A.S. Arora: Stachybotrys chartarum strain s72 contains 1.0x10-4 nanograms of satratoxin H per spore. 10 billion spores of s72 S. chartarum must be present in a single cubic meter of air to produce one milligram of satratoxin H per meter of air. Dr. Arora continues: "... it was calculated that a no-effect dose [in rats] corresponds to a 24-hour exposure to 3 billion spores per cubic meter of air for an infant [human], 9.5 billions spores per meter for school-age children, and 22 billion spores per cubic meter for adults."
Dr. Arora did not expand his discussion to address any potential cumulative toxicity of longer term exposure to lower levels of mycotoxins in buildings.
This "toxic black mold," Stachybotrys chartarum, infamous thanks to media attention, is not designed for airborne transmission, being large and sticky.
Indeed we often find S. chartarum mold spores present in air samples when a dense colony of such mold is being mechanically disturbed, such as during demolition. But we have never seen it in air anywhere close to the levels cited as the "no-effect dose." We believe that we've been barking up the wrong mold-tree, and that one would be smarter to look in buildings for the Penicillium and Aspergillus families which spread throughout a building easily by airborne transmission
REFERENCE: Content of this section paraphrased and others quoted from a guest column, "Understanding the Health Effects of Mold," by Dr. Ajit S. Arora, MD, PhD, appearing in AIHA's magazine "The Synergist," September 2003, in the AIH Diplomate section, Pages vi-vii. Dr. Arora is a forensic medical examiner and medical toxicologist in Los Angeles. See partheniamedical.com.
"Clean" residential buildings are typically 230/m3 +/- 630.
We usually find only trace levels of Penicillium/Aspergillus indoors in residential buildings and offices, so counts even close to the "clean" level may make further investigation a reasonable course of action, particularly where the building houses occupants have complaints possibly due to mold, or occupants who may be at extra risk.
Holmberg (1987) associated Aspergillus spore levels over 50 CFU / cubic meter with sick building syndrome. We comment elsewhere that depending on culturing mold in buildings is unreliable since toxic or allergenic particles may be present but may be of a species or genera which either does not grow on a culture medium, or which is overgrown by something else on the medium.
Further, relying on settlement plates to culture mold produces quantitatively skewed results since different particles settle out of air at different rates, confounding an estimate of their numbers. Anderson™ multi-stage samplers which develop culturable samples attempt to overcome the particle size problem.(C)Trap DJ Friedman
Aspergillus sp. may be the most common and serious airborne mold problems in buildings: Opinion: from the author (DJ Friedman) based on extensive field investigations and laboratory work, we suspect that several species of Aspergillus are probably the most common and widespread problem mold found indoors in buildings. These spores are small, easily airborne, grow on a variety of surface materials, and move readily throughout a building almost like a gas (due to their small size) riding on building convection currents and remaining airborne for long periods of time.
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs)
Question: can long term mold exposure affect the immune system?
I have a friend who has been working as a kitchen manager at a nearby college for over twentyfive years. Six years ago she came down ill with something no doctor could diagnose. She was actually off on sick leave for just over a year before she could sufficiantly recover to go back to work. Every symptom named in Mold sickness were present. Now after being back at work for a couple years, same job, she is again crashing. Same symptoms. A couple months ago, there was a wall torn out to fix a leak behind the steamer that had been there for years.
It came down the wall from an upstairs bathroom and it was a small leak that was tolerated and cleaned up daily. When finally the problem was fixed the walls inside the kitchen was evey color imaginable and a large portion was torn out and replaced. Mold remediation was not called in and a warning was given to the staff present at the time, that nothing could be said for surely the college would be shut down and extensive work would have to be done. She decided to retire since she it too tired to mvoe these days. I went with her today to clean out her desk.
I have had chemical poisioning year ago and If there is any kind of chemical reaction going on, including mold, I immediatly fell the mold spores light, as if it were on my skin. It feels like a tiny pinprick and begins immediatly to itch and soon spread all over my body. I break out in red welts. I sat in her office today while she emptied her desk and locker. By the time we got back to the vehicle to drive away, I realized without a doubt that I had been in the presence of airborn mold spores. By the time we drove the twenty minutes home, I had to strip, take a shower, wash my cloths with bleach and take a benedryl. I think she has had long term exposure to the mold and therefore, her immune system is highly effected. What do you think? - Chaplain CJ Echols
It sounds as if you and your friend needs to consult a doctor who is expert in environmental medicine for expert help in both diagnosis and treatment. Ask the doc what sorts of contaminants or exposures are most likely to cause or aggravate the complaints.
Question: Accurate mold counts? How do we know if our school is safe?
So reading this article it seems that accurately determining mold counts is very tough. So how do we know if our school is safe? We do know that there has been a lot of black mold found behind walls and other places. And that indoor mold counts in some classrooms is about 5000 count per cubic meter. But what do we do now? The administration just says 'It's fine.' - My school has mold
Reader follow-up comment:
Yes.. I agree.. the 'All if fine' routine from admin and the superintendent is a bit worrisome. But no one seems to be doing anything about it. Any idea who or what department or agency I should call to look into this? Thanks!!!
MOLD EXPERT, WHEN TO HIRE will give you some help in deciding if it's appropriate to bring in an independent expert; if so, you'll then have a credible third party who can provide information to your school administrators. There may be legal or procedural issues about who has authority to bring in someone - be sure you've resolved those before hiring anyone.
Question: how to interpret airborne mold count levelsk, 1833 Aspergillus/Penicillium outdoors & 8553 indoors?
My workplace has a mold problem and a air sample analysis was done in August. I just got a copy of it as my doctor requested it. Question is - report shows outside level of 1833 or 4.2% Aspergillus/Penicillium and inside count of 8553 or 97.0% per cubic meter of Aspergillus/Penicillium. What do these numbers suggest? All 6 employees are having health issues.
Question: Are there health risks to building occupants during duct cleaning & ceiling replacement?
My company is having the building cleaned, the ductwork replaced and ceiling tiles replaced. They have been telling us that there is no health risk to us working in the building. The report that I was given really doesn't say how bad the air quality is. I am just a small fish at the bottom of a very large corporate pool and told I have a job to do. - Anonymous
There may be OSHA or other regulations that should guide cleaning or renovation work in your building, and if hazardous materials are present that is surely the case. More generally, if the cleaners in your building are taking steps to control the release of dust during the work, such as setting up containment, using negative air machines, or HEPA vaccuming, or if the work is being performed in areas whose air and dust does not readily enter the work area, the risk to occupants is of course reduced.
Question: Following a death due to mold exposure in a building, how long can the spores live after the source has been removed?
How long can the spores live after the source has been removed? How serious is the contamination of personal items in the home and how long after the source is removed, are they safe if ever? More specifically, we are dealing with exposure to a home 4 years after a death occured in the home due to mycotoxicosis of asperigillus and stachybotrys. The original source of the mold was not in this home, but rather at a work place.
A year after the death, family members and a caregiver came down with symptoms and now test positive for the same toxins the family member died of. They claim the house is cross contaminated and abandoned it. 3 years later, we were hired to clean out the home and just found out this information. 3 years ago at the time of the abandonment, the house was tested and found to be 16 times the normal levels of the mold spores.
Unknowingly, we brought items into our home, donated items to friends and charity, and cleaned the entire home with out face masks or respirators. A 3 year old child and pregnant woman were also exposed. Should we be concerned? - Tracey
Reply: dead mold spores may still be a problem; but small or sub-acute levels of moldy dust without an actual mold growth reservoir are not normally a problem
If you continue to be concerned about having imported moldy dust into your home you should take these steps to reduce that concern:
Make sure that your own home does not have its own leaks, moisture problems, and hidden or visible mold growth reservoir, independent of any dust that you may have imported.
HEPA Vacuum and wipe dusty surfaces in the home
Wash or dry clean clothing that may have been exposed to high levels of moldy dust or other problem dust contamination
Change air filters in your heating or air conditionong system
See MOLD EXPERT, WHEN TO HIRE for more advice on how to decide if it is appropriate and justified to bring in an expert to survey the building for problem mold contamination or other IAQ worries.
Question: can you refer me to a mold inspector in Germany?
Can you recommend mold inspectors in Kaiserslautern Germany? I am in the US Military and recently moved here and think I have mold in my rental house.
Reply: sources of mold experts and advice on choosing one
Brian, you should contact your base medical and health officers for advice on inspecting your home for health worries, and see MOLD EXPERT, WHEN TO HIRE
Moldy odors are produced by some, not all, species of mold, and even then, not in all conditions. The production of MVOCs (mold volatile organic compounds) that you smell in air depends on the genera/species of mold, the surface on which it is growing, and growth conditions such as moisture, temperature, light exposure. And similarly, mold spore release is a natural event that occurs depending on growing conditions as well as on mechanical disturbance such as during demolition or cleaning.
Question: Can you Interpret my Mold Test Report?
My Mother had some testing done for mold in her home. I was hoping that you could shed some light on this. This threw her into panic mode. She has had some sinus problems which could be related to this mold in home. I am reaching out to you so that we know how quickly this needs to be remediated. I have attached a Mold test report [edited to remove personal information - ed.] that I was hoping you could decipher or point me in the right direction of a company that I could reach out to here in Wyoming, Michigan where my Mother’s home is located.
I believe she does have some moisture problems as she has some peeling paint in most rooms of the main level. For years she has worried about the insulation in the attic but just too busy to get to the source of the problem. Thanks - A.R.
We took a look at your mold test report and note that your mold investigator through visual inspection and lab report concluded that professional mold cleaning is needed at your home. As we have not seen your property much less inspected it, in my opinion the person whom you paid to examine the home should be the first one in line to answer your questions about how to proceed. If s/he does not provide the service of explaining what was found and what you need to do about it, we might wonder what you paid for. Certainly in our opinion it would be a unconscionable to have to hire a second person just to explain what the first one said.
We agree with the approach of answering a mold remediation need question through a combined building inspection for visual evidence of the location and extent of mold contmaination, an interview with building occupants to estanblish the history ofthe home and possible occupant health concerns, limited testing to confirm that the mold seen is not just "cosmetic" is appropriate in some cases, and the combination of the experience of the inspector and lab results with the application of general mold level standards described by a reasonable and non-quantitative industry standard IICRC S520: Standard and Reference Guide for Professional Mold Remediation 
Watch out: you 'll want to be sure that the inspection of the home was thorough and that it identified both all areas that need mold remediation, the extent of remediation needed, and the causes of mold growth that need to be corrected. Without that level of information, in other words, a professional mold remediation plan, not just a "test report", you are at risk of wasting money by doing an incomplete job.
Question: Why are there no mold standards for the workplace?
Would you be able to help me/us?
Thanks again for getting back to me so quickly. - K.O.
Reply: Giving any single number for allowable mold exposure as a "standard" borders on junk science
Thank you for the interesting question - it helps us realize where we need to work on making our text more clear or more complete. A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem including addressing the question of whether or not there is in fact an indoor environmental hazard in your workplace.
Your statement that "mold was found..." itself is not diagnostic - I can find some mold in just about any building, new or old, anywhere in the world. Whether or not that constitutes a health risk depends mostly on the size of the mold contamination, also on how mold spores may become airborne and move through the building, and of course the genera/species of the dominant mold present - ranging from harmless cosmetic to seriously harmful.
I am also interested in your posing of the question " why is there no standards for mold in the workplace?" Often people will pose a question in a manner that presumes a-priori something that is simply not true - a silly example is the old saw of a legal question "Are you still beating your wife?" which presumes the individual ever beat his wife at all in the first place.
Actually there are dozens of attempts at "mold standards", both quantitative (questionable as I explain below) and qualitative (sensible as I explain in the article above) as you can see in the references section of this article. That said, here are some things to consider in answering your presumptive question.
Take a look at MOLD EXPERT, WHEN TO HIRE for criteria that help decide if hiring an expert for a building is needed. Basically, if you see more than 30 sqft. of non-cosmetic mold indoors in a building (a few indoor molds are cosmetic only) then professional mold remediation is in order, period, and your building management would be mistaken to conclude otherewise. For cases where a large problem mold reservoir is not immediately visible and obvious, this article could be most helpful to you in deciding if there is reason to believe your workplace has conditions that make further, expert investigation appropriate.
Why single number mold standards are not accurate nor very useful
Mold "standards" that give an acceptable or unacceptable number of spores are really close to nonsense except at such very high levels as to be both unambiguous and not useful for less obvious mold contamination problems. In other words, at very high levels of problematic spores there is no argument that there is a problem to be found and removed. But that sledgehammer approach is not useful.
There are 1.5 million species that vary in toxicity to about 3 million levels if one adds the effects on toxicity of the substrate on which mold is growing. You'd need standards for each mold species by type, weight, growing conditions. The health effects of inhaling a specific genera/species of spore are so widespread, that a single numeric standard would just be junk science. Add to that the enormous variation in the "exposure level" found by different approaches to testing and the impact of varying building conditions, air movement, temperature, occupancy etc. looking for a standard is waiting for Godot.
Add to that factor a wide range of human or other animal response to mold exposure and a standard becomes still more difficult. I've instrumented some clients who responded with extreme distress to very low levels of airborne Aspergillus sp. (less than 300 spores/M3 of air) for example - an airborne mold level well below most accepted opinions of "what level of mold describes a contaminated building?"
Even the standard of comparing indoor to outdoor spore levels is highly questionable - since we can and usually are comparing numbers of completely different molds - an apples to oranges comparison.
However it is possible to combine an expert and complete outdoor and indoor and mechanicals system building inspection, interviews with building occupants, and some testing to guide a decision on what cleanup may be needed in a building. An experienced building diagnostician will consider some very general rules that help point to the presence of absence of a problematic indoor mold reservoir that needs to be found and removed and its cause corrected. "Testing" without a thorough inspection and interview is frankly not reliable.
What should be the approach to evaluating a mold-suspect building?
What is needed is an approach to deciding if there is an actionable problem in a building where obvious hazards (such as more than 30 sqft of problematic mold contamination) are not immediately apparent. And the conditions of exposure matter too. A worker whose job requires spending hours a day in a moldy automobile such as the one illustrated above could be exposed to serious hazards even when the total square feet of moldy material could be as small as just the interior of the vehicle air conditioning system. Details of moldy automobile hazards are at CAR MOLD CONTAMINATION
References to some helpful articles on mold standards, testing, expertise and need for an investigation
Please keep me posted on how things progress, and send along photos if you can. Such added details can help us understand what's happening and often permit some useful further comment. What we both learn may help me help someone else.
Question: what are safe and reasonable airborne mold counts for a home?
to editor Hi, I have been trying to find a source that lists what are considered to be safe and reasonable mold airborne counts for a home. Do you have this or can you direct me to a resource. Appreciate your help. - P.P. 5/17/2013
The third article points out that airborne mold counts are close to junk science because of the range of variability that encompasses several orders of magnitude.
Furthermore, since among the 1.5 million or so mold genera/species there is wide variation in particle size, probability of growing as an indoor mold, and toxicity, it is rather unreliable to consider only "mold count" without knowing something about what mold is actually present in the building as well as what molds are being detected in a test.
Let me know if any of that material is unclear or confusing and I'll do my best to help further.
Question: how to interpret an indoor mold air test and inspection that found no actionable contamination
I saw your website and it is very informative. I work in a library that I believe has mold due to water leaks, although there are no outward signs of mold. An air quality test was recently done and it showed some fungi spores such as Bipolaris and Cladosporium, but the outside air quality was shown to be much worse and I do not see how that is possible.
A comparison was made between the outdoor and indoor air and their conclusion was that "The bioaerosol results in [Anonymous] Library for total fungal spores did not identify an amplification or biodiversity of fungi between the indoor and outside sample."
No recommendation was made because I assume they feel that the indoor air is a minor issue when compared to the outdoor air. I have been having high blood pressure when I am in the building, but my blood pressure goes down to a normal level when I am outside, so I do not see how the outside air could be much worse than the inside air according to the test results. If I sent you a copy of the results via email, would you be willing to look at it and to see if this test looks legitimate? - Anonymous [data on file] 1/22/2014
Send me the report and I can comment. Keep in mind no remote analysis is a substitute for an onsite expert. I will take an initial look and comment pro bono. ...
[Reader provided a copy of an indoor IAQ inspection and test reports provided by an industrial hygienist. The hygienist performed a visual inspection, tested CO2 levels, and performed some air tests for mold. - document on file]
The details of the tests and lab report do not find evidence of an indoor mold contamination problem.
None of the species found in the actual "test" included the more problematic indoor spores that are most common in buildings where there is a serious mold contamination issue - such as in the Aspergillus group (highly airborne, small particles, breathed deeply into lungs, pathogenic or toxic) nor of the mycotoxin group such as Stachybotrys chartarum that is often found on wet drywall.
While the hygienist cites that there are no mold exposure standards, that is not quite the case. While I argue vigorously that a simple quantitative standard for mold exposure would be junk science (individual mold spores vary enormously in size, toxicity, airborne or other exposure pathways, so we would need hundreds of standards), nevertheless, experts have shown that there are general indoor mold levels that strongly indicate that a building has been subject to leaks and / or that there is probably an actionable (that is large) mold reservoir in the building. See MOLD STANDARDS for details.
And even when indoor mold test counts are low, on occasion one may find subtle clues that mean one could infer by looking at mold genera/species found indoors (which certainly were not matched to the outdoor spore mix) provide a very weak or low-level suggestion of water intrusion or leakage - that is, we see some mold growth that might be associated with water leaks.
The risk in any air test is that the airborne spore level can vary by several orders of magnitude depending on how the test is conducted. So absence of evidence of a mold problem when we rely principally on an air test is *not* proof that no problem is present.
But absence of such evidence, when combined with an expert inspection of the building for visual clues suggesting an actionable risk of a hidden problem reservoir (such as mold contamination in a ceiling or wall cavity) can add up to a conclusion that the expert could not find any justification for more invasive or extensive inspection steps.
I cannot comment on how expert the visual inspection was at your building. The reliability of that step depends largely on the particular experience and building-science knowledge of the inspector.
I can comment that comparing indoor air with outdoor air, while a very widely used practice, is rarely actually useful. Too often the genera/species are so different that simply comparing "spore counts" is nonsense - as comparing apples and oranges. The hygienist's own report makes this same pont.
I can add that sometimes, even very low levels of certain problematic mold spores in an indoor sample (such as Aspergillus spores in chains) can be detected by an astute lab technician and interpreted by an astute investigator as reason to look further for a building problem. At InspectApedia.com we have published a series of articles about these sources of error or of discovery should be considered by hygienists or other professionals who inspect or "test" buildings for mold or other similar contaminants. Two you may want to read are
The first article introduces the huge variation in airborne particle levels from minute to minute in a building as well as other sources of error that can overwhelm mold test accuracy.
The second article is interesting because a careful read of a typical mold-in-air test will show that sometimes data is being given where only a single mold spore of a given genera/species was actually detected. At that excruciatingly small count level one should not get excited about the translation into percentages. For example if indoor air contains "25% of toxic mold type X" and then we read that only four spores were detected in the whole sample, and one of these was type X, then such numbers are of little import. The devil is in these details.
In sum, nothing in the report you provided points toward an actionable indoor mold contamination issue nor documents a basis for more invasive further inspection or testing. That's not to say that the building is guaranteed "problem free" but it is reasonable to opine that an expert has examined the building and found no evidence that justifies further such action. For a more thoughtful look at how we decide when expert building investigation is probably warranted, see MOLD EXPERT, WHEN TO HIRE
If you are still convinced by your own experience that the building is responsible for personal health complaints then you will want to confer with your doctor and document his/her opinion, or that of a referred expert in environmental medicine, that your complaints are environment-related, caused, or aggravated.
For example, your doctor might cite other reasons for elevated blood pressure (your complaint) than an environmental one. Mold contamination itself is not usually blamed for high blood pressure, but in my opinion stress, including environmental stresses or even simple anxiety could be relevant factors.
If that conclusion is indeed reached, then next would be an examination of all environments where you spend the majority of your time, to see what can be found, if anything, that should be addressed.
Finally, I recommend caution against becoming a victim of a "capture error" - that is, don't let a specific fear that has come to mind (mold contamination) prevent you from looking more thoughtfully and broadly, and with medical advice, for the cause and thus recommended actions around a medical or health complaint.
Questions & answers or comments about standards for acceptable or unacceptable toxic mold spore counts, levels, or measurements in building interiors.
Try the search box just below or if you prefer, post a question or a comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.