Archive for April, 2010

Mold: The Whole Picture, Part 4: Effect of Mold on Schools, Homes, & Human Beings

by Ellen McCrady
Ellen Ruth McCrady, publisher of Abbey Publications and editor of the Abbey Newsletter, Alkaline Paper Advocate, and The Mold Reporter passed away on March 5, 2008.


When Pasteur demonstrated in the late 1800s that bacteria caused disease, it took a long while for the public to get a clear idea of what bacteria were and how they did what they did. In the 1930s, many people thought you could catch conjunctivitis by looking at someone who had an infected eye, and even today most people do not know the best way to avoid infections in general.

Still, most people agree on the basics: You catch an infection from other people, because a germ invades your body through broken skin, the digestive system, or lungs. If it makes you very sick, you go to a doctor, who will diagnose you and maybe take a blood sample to confirm his diagnosis. Then he will treat you with drugs or a shot of antibiotics and other therapeutic measures. He may have to operate. You go to bed, and if you do not die, you will get well, though you may carry scars (smallpox) or be otherwise disabled (polio).

When people are made sick by mold, it’s a whole new ball game. You do not catch mold spores from other people the way you do germs. You catch them from buildings, or the materials you work with. The longer or more intense your exposure, the sicker you get. What makes you sick is usually not the organisms themselves, but the airborne toxins and allergens they produce. You may become so sick that you have to go to bed, but your doctor will probably not know how to diagnose you and you may look healthy to your friends. Even if you do get diagnosed, your medical insurance will probably not cover your treatment expenses. If you lose your job and your health, and sue the landlord to get the money for medical expenses and loss of income, chances are very small that you will win in court, because it is virtually impossible to prove to a jury that your health was damaged because of mold in the building. Juries need the equivalent of a smoking gun, and so far, there is no foolproof way to connect a moldy building with a sick person.

Even after you think you have recovered, you have not gained immunity, as you do after you have had chickenpox or measles; in fact, you may be more vulnerable to future exposures than you were to start with, just as you would be after exposure to other common toxins, such as lead.

(Gary Frost, in a recent letter about his own experience with mold, concluded by saying, “Mold is certainly smart. It is stunning to realize how opportunistic ‘primitive’ organisms are and how they maximize any benefits from change in their environments. These organisms don’t need evolution…. They are responsive enough as is.”)

Besides the responsiveness, or adaptation to different conditions that Gary mentions, they mutate with relative ease, and they associate with other microorganisms in proportions that change as the conditions change—i.e., as a location grows moister, the proportion of Stachybotrys species will increase, and so on. So it is hard to tell what you are dealing with.

In the tropics, the situation is even more serious. J. David Miller, in his excellent paper, “Fungi as Contaminants in Indoor Air,” says,

In the cold climate of Canada, very few people encounter someone who dies from a fungal disease. This is not the case in tropical countries where diseases caused by fungi are common. There are a number of invariably fatal systemic infections as well as skin and nail mycoses and lung infections. Diseases caused by ingestion of fungal toxins [i.e., eating spoiled food] are leading causes of death in tropical and subtropical countries, especially liver cancer induced by the ingestion of aflatoxins, esophageal cancer caused by some Fusarium toxins and deaths caused indirectly by the excessive consumption of immune system depressors such as the trichothecenes (1).

Reports of Mold-Infested Schools and Homes

Papers given at conferences may give statistics on moldy homes and schools as part of a larger picture, but somehow personal and newspaper reports of individual schools and homes are better at showing how mold can affect peoples’ lives.

In a suburb of Dallas about six years ago, according to a 1997 report in the Fort Worth Star Telegram, health officials were puzzled by the illness of a suburban woman, who had suffered from flulike symptoms for two weeks after she moved into a condominium. A regional industrial hygienist with the health department was quoted as saying that “the neighbors found her crawling around on her hands and knees complaining of earthquakes.” Health officials investigated her case and found that her illness was caused by fungus in the air-conditioning ducts of her condo. The industrial hygienist was quoted as saying, “She was totaled. Her system was overwhelmed. She was in the hospital for 60 days before they got her cleaned out.”

The news report goes on to say that public knowledge of fungi does not reach far beyond mushrooms, athlete’s foot and yeast infections, despite its deadly potential. Michael Rinaldi, a mycologist at Audie Murphy Veterans Affairs Hospital in San Antonio, is quoted as saying that in the last 10 years mycology, the study of fungus, has become one of the most critical in all of medicine.

Susceptibility to fungus varies, it says. Infants, the aged, asthma patients who are being treated with steroids, and people with weakened immune systems are most susceptible. (The author failed to mention one other important group: women. In some occupations they are several times more likely to be affected than men.)

CNN Interactive, a website, had a story in November 1997 on a post-flood case of Stachybotrys growth in West Bloomfield, Michigan. The 14-month-old granddaughter had developed breathing problems, and the grandmother was getting headaches and often felt ill, especially when she was in the basement. These troubles came after the spring rains that flooded the basement, bringing on the growth of Stachybotrys, visible only as a small round black circle on the wall.

Dr. George Riegel of Healthy Homes commented on this incident, saying that few people who clean up after a flood do a professional job and contain the area (with tape and plastic sheeting), with the result that the mold spreads to other parts of the house. To remove it safely, he said, would cost that family close to $10,000. He also said that most black molds are not Stachybotrys. Stachybotrys grows only on wood and paper products, and can be found in only about 2 to 5 percent of American homes.

The grandmother said the news was rather unnerving. “I am ready to move, but where am I going? This is my home. I can’t afford to just pack up and leave.”

Hill Elementary School in Austin, Texas, was closed down at the beginning of March and students assigned to other schools when mold (a lot of Penicillium and a small amount of Stachybotrys) was found in the outer rooms in the main building. Further investigation revealed that the annex buildings and portables also had mold.

As usual, in cases like this in which a thorough investigation is done, several conditions were found to have contributed to the overgrowth: a spring in the crawl space beneath the building after rains (not a big problem); poor ventilation (air pressure higher outside the building than inside—a big problem, because this draws in contaminated moisture); condensation from cool roof beams, which dripped into the school walls (since the moisture barrier at that interface no longer was able to stop it); skylights (always potential sources of water troubles); and (as in most schools), outer walls lined on the inside with moisture-impermeable chalkboards, bulletin boards and cabinetry, all of which tend to trap the moisture within the walls.

Since the demolition is not complete yet, more pockets of mold and decay may come to light. The outlying buildings (annex and portables) have been found to have mold contamination too. The school board has authorized the schools superintendent to spend a million dollars to correct the problem. No one can be sure that the building will be ready for the fall semester, four months away.

The children were getting sick and parents were complaining last fall, months before the condition of the school was recognized as a problem.

The local paper ran a letter to the editor recently from someone who has been through this kind of crisis before. It says, in part:

Stachybotrys was found in a Bryan school building in 1996. I know because I was the principal. I requested environmental studies be conducted by a biologic hazards company. Instead, the district hired an industrial company unfamiliar with mold problems. Two environmental specialists reviewed the findings and found dangerously high levels of Stachybotrys as well as other molds. My health deteriorated, and I was granted disability retirement by the medical board of the Texas Teacher Retirement System because of the effects of toxic exposure to Stachybotrys.

My heart goes out to the staff and students who are still in the Bryan building.

A story about mold contamination of hospitals was sent to the Aspergillus discussion list. It was from a subscriber in Finland, replying in sympathy to someone who had observed water damage to ceilings in five hospitals she had been in. The Finnish subscriber said, “In my country too we have many mold-contaminated hospitals (at least 3 central hospitals), unfortunately.


“One of my friends has been diagnosed with occupational allergic alveolitis; she had been working in a mold-contaminated library, which was closed later and the staff was moved to another building. She complained that she got bad symptoms whenever she was in her central hospital. All the staff, even doctors, denied mold problems and said she was wrong. Now 3 wards of this hospital have been closed for mold reparation!!!”

[To find information about Aspergillus diseases, the Aspergillus web site, e-mail group moderators, the e-mail archive, FAQs and e-mail list commands, go to http://www.aspergillus.man.ac.uk/listinfo.htm].

Another subscriber to the aspergillus mail list, Danitza Shanahan, contributed the following story to the list March 9. She saw it on page 24 of the Arizona Republic for March 5:

New Home Becomes a Horror

Mold Endangers Children’s Health
A Mother’s Dream
by Beverly Ford

When Michelle Harless finally scraped up the money for her first house, she thought she was prepared for the rigors of home ownership. But within months, her Glendale dream home became her worst nightmare. The stuff of that nightmare: mold fed by a leaky pipe.

Four months after moving into the three-bedroom house, Harless’s 7-year-old son, Thomas Fuller, who suffers from cystic fibrosis, had to be hospitalized. Two months later, he was hospitalized again. Doctors said Thomas had lost 33 percent of his lung function because of a common but sometimes toxic mold, called aspergillus.

“When it came back aspergillus we were blown away,” said Harless, 26. Her 2-year-old son, James Hatley, wasn’t immune, either. He lost his appetite, developed red, cracked skin and began coughing and sniffling. Doctors thought he was suffering from seizures. Harless knew otherwise: It was aspergillus mold.

Then, she said, things went from bad to worse. Harless’s insurance company told her that her policy didn’t cover mold infestation. “I thought I did everything right,” she said, “I had a home inspection. I had homeowners insurance, I had a home warranty. But it’s a nightmare.”

For weeks, Harless tried to convince the company that the mold was caused by a leaky pipe, which was covered under her policy. But the company stood firm. And despite her son’s health problems, the company refused to reimburse the family for moving into an apartment, she said, or to pay to clean up the mold that had by now permeated the home.

“I felt trapped,” Harless said. “Mold affects healthy people, but for my son it was a life-and-death matter.”

The insurance carrier, Century National Insurance Co., declined to comment on Harless’s claims. It was only when an insurance adjuster put up the money that Harless and her family were able to move into a nearby apartment. Soon, both children’s health improved, although Thomas’s lungs remain permanently damaged, she said. Harless and her husband continue to make payments on the $91,000 home while they wait to see whether their insurance company will pay for repairs. The firm has sent inspectors to examine the home and recently offered to work out a settlement.

A case similar to Michele Harless’s, only worse, was reported in USA Weekend for Dec. 3-5, 1999. It starts out this way:

“It started with a series of leaks. Within a year, Melinda Ballard’s 11,500-square-foot Texas dream home was quarantined; her 3-year-old son, Rees, was on daily medication to treat scarred, asthmatic lungs; her husband, Ron Allison, had lost his memory along with his job; and the family was living out of suitcases and locked in a seemingly endless battle with their insurance company. The problem? Household mold [Stachybotrys].”

This family is not poor: the house sits on a 72-acre estate in Dripping Springs, west of Austin. She is described as an heiress. But now she has to put on a HEPA mask in order to enter the house, which she does once a week to check the air conditioning. The men who are cutting out the moldy timbers have to wear moon suits. David Straus, a mold expert with the Texas Tech University Health Sciences Center, spent just 30 minutes inside the house, but was throwing up hours afterward, and now has severe hearing loss in one ear from the mold. The family suffered from headaches, dizziness and fatigue, then respiratory and sinus problems, in addition to profusely bloody runny noses and coughed-up blood.

The family is suing their insurance company (Farmers Insurance) for $100 million, and the County District Attorney has initiated a grand jury investigation to consider criminal charges against the company.

Given the Usual Course of Events, What Options Do We Have?

If you suspect your building has a mild or moderate mold problem, try to identify its source or sources so you can avoid them, or do something about them, or direct the attention of technical people to them. If you have been affected, your own reactions may be the best indicator available. Take notes on the date, area, presence of moisture (especially after a rain), any apparent mold growth, and effect on you. Forget about setting out petri dishes or measuring the humidity of the air.

Early recognition of a mold problem, and identification of its cause and remedy, can keep the mold from getting a head start if you have done your homework, provided the financing and approval for assessment and remediation can be found. The above instances show that residents and staff in a moldy building have no good options left if the mold gets a head start. This situation may eventually change when buildings are built and maintained to prevent moisture accumulation, when doctors learn to recognize the effect of mold exposure, when lawmakers require insurance companies to cover people affected by a mold disaster, and when mycologists are able to make an airtight causal connection between the presence of indoor mold and the health of people who inhabit the same space. Any change from the present situation will be an improvement. At present, though, rich and poor alike have only one good option: preparedness.

1. Maintain a list, compiled from references if possible, of all the experts you may one day have to call on (an informed doctor, a consultant who can assess the mold problem and advise on cleanup, someone who is knowledgeable about construction of houses and management of HVAC systems, etc.). The nearest one may be in another town.

2. Gather information: Buy books on the topic, visit informative websites, talk with informed people, get friendly with the building engineer and competent local service people who specialize in duct and carpet cleaning, join organizations that have mold prevention and recovery on their agendas, e.g. C.U.R.E. (Citizens United for Responsible Environmentalism, Inc., an international nonprofit education and research organization based in California, focusing on educating doctors and the public about mold diseases and toxicoses—tel. 408/268-4085, fax 408/476-8552).

One book that everyone should have access to has just appeared in print: Guidelines on Assessment and Remediation of Fungi in Indoor Environments, available on the Internet at http://www.ci.nyc.ny.us/html/doh/html/epi/moldrpt1.html (2) Future revisions to it will be posted there too. For more information, contact the New York City Department of Health at 212/788-4290. An expert panel was convened in 1993, originally to develop policies for medical and environmental evaluation and intervention in cases of Stachybotrys atra [chartarum] contamination. This revised guideline covers all fungi.

3. Follow developments in research and make contacts. Go to a mold conference now and then, or read in the professional literature on current research, to be sure your information is up to date. This will also make people more willing to talk to you; you can put yourself on a grapevine if you have recent news to swap. (As far as I know, there are no extension or college courses on coping with mold, except perhaps in the historical preservation field.)

4. Study real situations. Even if there is no leak to be found, water can enter a building through porous building materials, including concrete. It may enter as water vapor and condense and collect in hidden places. There are many esoteric ways for water to enter a house and feed mold. They are hard to understand without some kind of hands-on experience or a good teacher or a couple of really good books. So study is unavoidable.

5. If you have to leave your home or job despite everything, it helps to be on good terms with family members and friends who might be able to put you up in an emergency. A good savings account may be more use to you than medical insurance.

Picking Up the Pieces

If the mold problem is not too bad, or if the source of the problem is on neighboring property rather than inside your house, you could do as several C.U.R.E. members have done: install freestanding HEPA air filters in the office or bedroom, or even in every room in the house. Central HEPA filter units, with their own fan and air supply, can be installed as part of the central air conditioner. They work best if you have a good air return system. A good air filter large enough to handle a small or average bedroom can be had for $150-190. It will not work, however, if you set it on a deep carpet full of dust. This will just blow the dust up into the air. Set it on a stool or chair.

If you get really sick from mold, the first thing to do is to avoid further exposure (i.e., leave home or take extended leave from your job). Then ask your friendly local mycologist to recommend a good doctor. Or find an Internet list of doctors who can treat mold, and be prepared to travel, because there may not be one in your town. There are medicines nowadays that are effective against a fairly broad range of mold species.


1. Atmospheric Environment Vol. 26A, No. 12, pp. 2163-2172, 1992.

2. Guidelines on Assessment and Remediation of Fungi in Indoor Environments, available on the Internet at http://www.ci.nyc.ny.us/html/doh/html/epi/moldrpt1.html. the printed version, 14 pp. long, is issued by the New York City Dept. of Health, Environmental & Occupational Disease Prevention, 125 Worth St. c/n 34C, New York, NY 10013. It is intended for use by building engineers and management, but is available for general distribution to anyone concerned about fungal contamination, such as environmental consultants, health professionals, or the general public.

Mold Websites & Listservs Related to Health

  • aspergillus-on@mail-list.com (A listserv for people diagnosed with Aspergillus infections. A minor source of usable information; mainly serves as a support group.)
  • http://www.aspergillus.man.ac.uk/ (A technical website which offers an impressive variety of information, including the full text of a large number of medical papers. Registration is needed if you want to have access to all sections.)
  • http://www.chem.umd.edu/organic/jarvis.html (Analysis of 4 toxins, esp. tricothecenes, a kind of toxin produced by many species of mold)
  • http://isiaq.org/ (International Society for Indoor Air Quality. Good on buildings and air handling, but not on mold itself, or on health.)

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Mold: The Whole Picture
Pt. 3, A Neglected Public Health Problem

by Ellen McCrady
ABOUT THE AUTHOR:Ellen Ruth McCrady, publisher of Abbey Publications and editor of the Abbey Newsletter, Alkaline Paper Advocate, and The Mold Reporter passed away on March 5, 2008.

There have been so many stories in the news media lately about mold-infested schools and residences that I decided to skip the installments on remediation, buildings, and preventive measures for the time being, and go right to the personal narratives of people whose lives or health had been affected. In the next issue I will try to suggest ways to recognize the danger and describe some of the options available to victims. -Ed.

The first story appeared in the January 2000 issue of the WAAC Newsletter, in the Health and Safety column:

My name is Kim Harper. Seven years ago, I was exposed to mold. I worked in a small historical museum where I managed the archival collection and, later, the operations of a twelve-building museum village.

I absolutely loved my job working with artifacts and researching family history. Much of the archival collection was housed in a 100-year-old school house. For several months I sorted through water-damaged ledgers and artifacts. Many were covered with a black soot-like dust. After a few months, I noticed I was losing my balance, my short-term memory was failing, and I began dropping things. Sometimes, it almost felt like I had been drinking. These symptoms led doctors to believe I had multiple sclerosis. My health was deteriorating rapidly.

My asthma, which was previously mild, began to bother me daily. I was taking up to 14 doses of Ventolin a day at work. My asthma became so bad that after ten months of working at the Museum, my doctor ordered a lung function test. This test showed my lung function had dropped almost 20%.

I went on to develop intense joint pain and fatigue. At first, I thought I was just coming down with the flu, but it never went away … never. This unusual flu-like illness caused confusion, extreme fatigue, and joint pain. I recall asking my board members to write down any requests because I would forget what they wanted by the time they left the building.

Slowly, I was forced to cut back extra volunteer work at the Museum. I left my Trustee position with the School Board and eventually had to leave my part-time job, and finally my work at the Museum. I went on sick leave for two months. My asthma and cognitive symptoms improved almost 90%. But this all changed when I returned to work.

After two weeks back to work in the archives, my breathing, fatigue and joint pain began to worsen. I was asked to clean a damp, 100-year-old furnace room that had chronic water problems and mold. Within two months, my lung function had dropped another 20%. I was taking several pain medications to get through the work day and up to 20 puffs of Ventolin. After two severe asthma attacks where I could not breathe, I was forced to leave work permanently. I realize now, I should never have returned to work after my sick leave. Since starting work at the Museum three years earlier, my lung function had dropped a total of 36%. My lungs were working at only 44% capacity.

After leaving work, my asthma did not get better as it did with the first sick leave. Over the next year away from work, I spent many days in hospital to help my breathing. In order to stay out of the hospital, I was forced to take large doses of medication to manage even the simplest of tasks. Doctors prescribed 38 puffs of medication a day along with Prednisone.

I have never been well enough to return to work. You see, we realized too late that work was causing my health problems. I now know that I should never have cleaned the old furnace room without proper protection.

My health has improved slightly since leaving the Museum. But without medication, my lungs are still bad. Since 1992 I have never been pain free. I have trouble managing daily activities and was forced to move from my two-story home to a home with fewer stairs.

Mold is everywhere, but if you have to work with it, take a few extra minutes to learn about it and make educated choices to protect yourself. If workers are having problems, they should stop working in the contaminated environment immediately. I would encourage them to go to an occupational health specialist experienced in the effects of mold. By knowing exactly what is making them sick, they can take the necessary protective steps. You should know that some workers will never be able to work in a contaminated environment once they have been sensitized. I only hope that everyone will understand a little protection and knowledge goes a long way.

We know many of us would never want to stop working in our exciting field. There is no need to panic, we just need to take a practical approach and take the time to get informed and protect ourselves. This way we can continue to work with the artifacts that we love so very much. Someone has to preserve our history.

If anyone would like to learn more, or would like to share their experience, they can contact the Harper Archives at mkharper@netcom.ca.

Regards, Kim Harper
Whitby, Ontario, Canada

[On March 16, Ms. Harper sent an e-mail message saying, in part, “I am happy to learn you are getting the word out to others…. We have spent years learning how to remove and protect our artifacts from the ravages of mold. I’m glad it’s time for us to spend some time on protecting staff. Every week I see an increased concern in dealing with the toxic effects of mold.”

[She recommended that interested people contact her at mkharper@netcom.ca, where she can provide feedback, suggest websites and literature, and discuss how to approach your employer or Health and Safety Committee. She also suggested looking into the following sites:

  • http://www.envirocenter.com/ENYOHPto review research by well-known expert in this field: Dr. Eckardt Johanning of the Eastern New York Occupational and Environmental Health Center in Albany, New York. He has helped museum workers exposed to Stachybotrys in Soho, New York. This site includes several resources to help identify and remediate molds. Early in March he discussed the health hazards of mold on the television program “48 Hours.”
  • http://www.radio.cbc.ca/programs/quirks/archives/98-99to listen to a 20-minute broadcast on “Librarian’s Lung.” The show interviews a few archivists and museum workers who share their experiences with mold and how it affected their health. You can also contact the radio station staff by e-mail at <<>quirks@toronto.cbs.ca>. Maybe they will do a follow-up.

[In the absence of clear guidelines from the government, she recommended that workers should understand how important it is to identify the suspect mold as soon as possible. “It can be as simple as taking a scotch tape sample,” she said, “and mailing it to a mycologist familiar with Stachybotrys and Aspergillus for identification. This way staff will know if they are dealing with a mycotoxin that needs more careful consideration. A photograph of the area also helps.”]

See also the Aspergillus Web Site

“This site is designed to provide information on pathogenic Aspergilli for clinicians and scientific researchers. The site includes DNA sequence data, a comprehensive bibliographic database, laboratory protocols, treatment information and discussion groups. The Aspergillus Web Site is sponsored by Alza Corporation and Ortho Biotech Inc. and the sponsors have access to the Web Site address book–as do all other Aspergillus Web Site users. The European Science Foundation has also made a contribution to the maintenance of the site.”

Robert J. Milevski, Preservation Librarian at Princeton University Libraries, related a personal experience with mold in 1994 on the Conservation DistList.


Part 1, Mold: The Whole Picture
Part 2, Assessment of Mold Problems
Part 3, A Neglected Public Health Problem
Part 4: Effect of Mold on Schools, Homes, & Human Beings


Ellen Ruth McCrady, publisher of Abbey Publications and editor of the Abbey Newsletter, Alkaline Paper Advocate, and The Mold Reporter passed away on March 5, 2008.

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Mold: The Whole Picture
Pt. 2, Assessment of Mold Problems

by Ellen McCrady
Ellen Ruth McCrady, publisher of Abbey Publications and editor of the Abbey Newsletter, Alkaline Paper Advocate, and The Mold Reporter passed away on March 5, 2008.

Part 1 (v.23 #4) emphasized the preservation community’s need for better contact with fields that carry out research and generate information about mold. These fields include medicine, public health, agriculture, indoor air quality, building construction, and historic preservation, in addition to mycology. The history and nature of mold were discussed, and several websites and publications were cited.

The plan for this series does not include a review of preservation literature or procedures on mold, because the scope is so broad already. -Ed.

Defining the Problem

The first signs of a mold problem are often deceptive: a moldy smell in part of a building, tired employees who are said to be suffering from colds or allergies, or visible mold growths on walls or books in certain locations. They are easy to ignore and hard to interpret, so health and building problems may not be investigated right away, although affected items may be cleaned or fumigated. (Note: Mold problems from fire or water disasters are not considered here, because they usually cause explosive mold growth, rather than typically chronic or recurring growth.)

In minor cases, formal inspections are of course not called for. The 1994 edition of the Guidelines on Assessment and Remediation of Stachybotrys Atra [Chartarum] in Indoor Environments says,

“The criteria for conducting an initial inspection include:

  1. presence of visible mold;
  2. evidence of water damage;
  3. symptoms which are consistent with an allergic or toxic response to Stachybotrys atra (e.g., respiratory illness, rashes and chronic fatique) and are severe enough as judged by medical documentation to result in lost work days.”

A new edition of this guide, which will apply to more species, is in preparation.

If the smell or visible mold growths are seen as indicators of a health problem, institutions and businesses may call in indoor air quality specialists, who will look for evidence of bacteria, viruses and other microorganisms in addition to mold. They will check for deficiencies in the HVAC (heating, ventilating and air conditioning) system that may be bringing polluted air into the building, or spreading the mold to uninfected areas.

However, indoor air quality people, industrial hygienists and environmental health professionals may not get the whole picture because they are trained mostly to monitor conformity to government standards for work-related exposures, and there are no standards for mold exposure.

Teamwork Recommended

It takes a number of specialists from different fields to do an adequate assessment of a mold problem in a building. The assessment should be thorough enough to justify an expensive remediation, if that is called for (cleaning, restoring, and rebuilding); and the findings have to be credible, if they are intended for possible use in a lawsuit.

Unfortunately, many architects, builders and building engineers do not understand how they are contributing to the modern problem of illness among residents or staff and the decay of building materials. The “tight houses” first built during the oil shortage of the early 1970s do conserve fuel, but they also create ideal homes for mold.

It is no coincidence that the 1993 Workshop on Control of Humidity for Health, Artifacts, and Buildings gave the title “Bugs, Mold and Rot” to both the workshop and the proceedings. The workshop following that one was held last summer during the same week as the 1999 AIC conference. Those proceedings will be available, probably in 2000, from the National Institute of Building Sciences (202/289-7800, fax 202/289-1092).

Almost every writer on this subject recommends a team approach. A health specialist has to be involved, because the effects of exposure to mold are so variable, and reactions to other microorganisms and non-biological agents are also possible. Biological agents often encountered in such investigations include fungi, bacteria, amebae, and viruses; allergens from plants, microorganisms and animals; toxins from bacteria and fungi; and microbial volatile organic compounds (MVOCs). There should be a specialist who knows how to find and identify them, estimate the risk they pose, and do the necessary lab work. Finally, the investigators should include, or be in touch with, someone who knows about building structure and systems, especially of the building in question.

An investigation strategy is outlined on p. 2-3 (ch. 2, p. 3) in Bioaerosols: Assessment and Control, the manual published in 1999 by the ACGIH (American Conference of Governmental Industrial Hygienists). First comes the health assessment of people in the building, then the bioaerosol assessment, and the building assessment. Then hypotheses are formulated about what could be going on, because many factors have to be identified, at least provisionally, before the data can be gathered efficiently. The sampling methods, health precautions, places to look, possible causes, and conditions to correct are all determined or at least influenced by the species of organisms involved.

Next the hypotheses are tested by gathering data about the environment, bioaerosols present, and medical aspects, and by consulting experts as needed. If all the data checks out, the investigators are ready to make recommendations on moisture control, cleaning, repair and so on. If it does not check out, then the investigators have to go back to Square One.

A Detective Story

Sometimes the search for the cause of complaints is not easy. One such case was reported at the 1998 Bioaerosols Conference in Saratoga Springs by Joseph Fedoruk, Steven Uhlman and Dean B. Baker (“Microbial Contamination of a Ventilation System Detected by Microbial Volatile Organic Compound [MVOC] Analysis”). A six-story building constructed in 1970 was given an award in 1997 by ASHRAE for its healthy environment; however, in 1995 the HVAC system had been re-engineered to increase the supply of fresh air. By 1997, the year of its award, it was already a sick building. People in one end of the building were feeling ill and complaining periodically of chemical odor.

Fedoruk’s company was asked to look at the building, but it appeared to have no problems: they found consistently low counts of viable molds, total spores and atmospheric bacteria, and good temperature and relative humidity. They took samples indoors, outdoors, and in both the complaint areas and non-complaint areas. There was no visible mold growth anywhere, although MVOC concentrations were much higher in the complaint area. In order to get to the bottom of it, Fedoruk (who is a medical doctor) saw the people as a clinician. Perhaps this inspired him to follow the trail of MVOCs upstream to see where they were coming from; he doesn’t say so in the abstract of his paper, the source of this story.

Then they inspected the HVAC system and found something that had been overlooked in previous building investigations: mist from a chiller tower that was being drawn into a principal air intake duct only 30′ away, along with mist from a condensate pan beneath the chiller tower. The intake duct was damp; still, no mold growth was visible from the outside.

When they opened up the ducts, however, they found mold, yeast and bacteria colonies inside—not on the duct surface, but on the joint adhesive. That was enough to explain the contaminated air inside. (One is reminded of the original incidence of legionnaires’ disease, where the hotel’s air intake was also located close to the cooling tower. The airborne bacteria from the condensate pan there were also sucked up by the air intake and delivered to the hotel guests inside.)

Fedoruk concludes that MVOC analysis provides a way to detect ventilation system contamination when neither visible mold growth nor measurable bioaerosols (spores, etc.) are present to help the investigator.

Sometimes, if there is no other way to tell where the main source of the mold is, then parts of the walls, ceiling or floors have to be removed to inspect hidden parts of the structure. This is, of course, destructive but sometimes necessary. In England and Denmark, trained dogs called “rothounds” are used to find actively growing dry rot in a nondestructive way. These dogs can detect a certain MVOC that is produced by Serpula lacrymans, the dry rot fungus, from several meters away; they can cover 20-50 rooms an hour and also search small areas inaccessible to humans.

David Miller says the surface area of visible mold is the best measure of exposure, though it is hard to determine accurately. Colony-forming units from airborne samples alone have no value. In order to determine the existence of hidden fungal growth in buildings, the method of taking air samples described in the American Industrial Hygiene Association’s Field Guide for the Determination of Biological Contaminants (1996) is valuable, because it provides a comparison of fungal species inside versus species outside. Other tools are being developed to measure individual exposures to fungi for research studies. Aside from the AIHA manual, a recent review of the methods for assessing fungal exposures can be found in: Dillon, H.K., J.D. Miller, W.G. Sorenson, J. Douwes and R.J. Jacobs (1999). “A review of methods applicable to the assessment of mold exposure to children,” Environmental Health Perspectives 107 (s.3): 473-480.


Before sampling is done, a plan has to be drawn up specifying which microorganisms will be looked for, where they might be found, likely sources, how the organisms will be located and quantified, and when and where samples will be collected.

There are many kinds of volumetric air samplers, among which the Andersen sampler is frequently mentioned. They draw in air from the room and discharge it with the bioaerosols onto a filter or sticky surfaces or agar plates.

Air samples can be used to get a count of “colony-forming units” (cfu, which are bacteria and fungi that start growing on the culture media) per cubic meter of air. If the colonies are easy to identify, the counts can be related to individual species. The cfu of mixed species may also be used as a broad index of microbial growth. When species are mixed, however, one or more species may be suppressed on the culture plate by competitors.

A well-known but unreliable way of taking a sample of bioaerosols in an area is to set out culture plates and let the spores and other bioaerosols settle on them. This method is rarely used today, because some organisms do not send out many spores, or have spores that are too light to settle out, or that die soon after they leave the colony.

The mold count can be increased hundreds or thousands of times by “aggressive sampling”—that is, by stirring up the air with a fan, or pounding on the wall. Higher counts are also had when there is traffic through a room, such as a schoolroom at the beginning or end of the day. So a great many facts and observations have to be recorded, and samples have to be taken by several different methods, in order to get reliable data.

There are no standard methods for getting information on airborne microorganisms, according to Brian Flannigan (in his paper,” Guidelines for Evaluation of Airborne Microbial Contamination of Buildings,” given at the 1994 Saratoga Springs conference). Assessment of only viable microorganisms may reveal as little as 1% of the total microbial airborne load, he says.

Samples of moldy materials (bulk samples) can be taken and pressed directly onto an agar plate, then cultured. Results are counted as colony-forming units per gram of material.

Samples of surface growth can be taken with sticky tape or a sterile swab, then transferred to a plate. This is a useful method for hard surfaces like the inside of an air duct.

An open and multidisciplinary approach is needed to make a complete, fast and efficient diagnosis of hidden mold problems in buildings. … [In the case of a Stachybotrys chartarum contaminated building], many critically important steps … are required to make your diagnosis a success story.

First, trust the occupants: if there is a complaint, there is a cause, even if it’s not obvious. Find it! Second, a thorough inspection of the premises and their ventilation is mandatory. Keep in mind that mold needs water and porous organic materials that can be hidden in the structures and not directly visible. Almost any building material can harbor fungal growth, if the available water activity is sufficient. Use the proper tools to find it. Third, if sampling is needed, be versatile: no sampling method is perfect. Adapt the sampling strategy to the situation and use an accredited mycology lab to count and identify fungi in your samples. Bear in mind that you are dealing with toxigenic mold and, depending on the extent of the contaminated surface, take proper action to keep occupants away from it and protect their health. Finally, after putting together all the data gathered in the field, always communicate it in a simple, straightforward way, with affordable step-by-step remedial: don’t forget that people want to get rid of their problem, not make their lives more complicated.

Claude Mainville, Sr. P. Eng.
President, Natur’air – Kiwatin Inc.
Montreal, QC H2L 1M1, Canada

[Reprinted with the author’s permission from the abstract of his paper, “Learning from Stachybotrys chartarum: How to Find Hidden Mold in Buildings,”given at the 1998 Bioaerosols Conference in Saratoga Springs, NY.]

Media and Methods

Opinions differ about which culture media work best.

A common medium used for fungi is malt extract agar. Xerophilic fungi like Aspergillus penicillioides grow better on a medium with a water activity (Aw) reduced by addition of salt, sugar or glycerol. The incubation temperature has to be within a certain range (18°C to 25°C for most fungi and as high as 55°C [99°F] for thermophilic species).

Sometimes, when time is short, polymerase chain reaction (PCR) will be used instead of culturing, because results can be had in hours rather than days or weeks, and identifications are certain and specific. PCR is especially good for identifying hard-to-grow, slow-growing and nonculturable organisms.

Even after samples are taken and cultures are grown, the findings have to be interpreted before remediation can begin, even for a small area or building. Interpretation may only consist of an individual’s weighing the evidence mentally, or consulting the relevant literature just to be sure. For a large building, however, all possible alternatives to each finding must be considered. There is a whole chapter on it by Harriet Burge et al. in the ACGIH book, Bioaerosols: Assessment and Control, but we will not go into that step here, except to warn that sometimes other microorganisms or even inorganic materials or sources outside the building can be at least partly responsible for symptoms of occupants. And toxins released by mold may greatly increase the effect of toxins from other sources.

Which Mold Species are Most Common? Most Toxic?

Opinion as to the most common species varies. A chapter on indoor mycology in North America (Building Mycology, ch. 11) says the most common fungal genera found in houses (present in 10 to 100% of samples) are Cladosporium, Penicillium, Alternaria, Streptomyces and Epicoccum. Brian Flannigan, who gave a paper, “Guidelines for Evaluation of Airborne Microbial Contamination of Buildings,” at the 1994 Saratoga Springs conference, says that the most common indoor molds are likely to be species of Cladosporium, Penicillium, Aspergillus and Eurotium. Fausta Gallo has identified Aspergillus and Penicillium as the most common species in libraries (1986, ICCROM).

Nominations for most toxic species also vary. Aspergillus fumigatus and Stachybotrys are two examples that Flannigan offers of moisture-loving toxic molds that can flourish indoors. He cites a Canadian guide on office buildings, which says that “Pathogenic fungi such as Aspergillus fumigatus, Histoplasma and Cryptococcus should not be present in significant numbers. The persistence of toxigenic molds such as Stachybotrys atra and Aspergillus versicolor in significant numbers requires investigation/action.”

Jeffrey Cooper and J. Michael Phillips listed the following five species as most toxic in a recent paper: Aspergillus flavus, A. fumigatus, A. versicolor, Fusarium moniliforme, and Stachybotrys chartarum. They say, “The detection of any toxigenic fungi indoors is considered unacceptable from a human health risk perspective. The confirmed presence of [any of these five species] requires urgent risk management decisions by building owners.” (“Assessment and Remediation of Toxigenic Fungal Contamination in Indoor Environments,” First NSF International Conference on Indoor Air Health, May 3-5, 1999, Denver, CO)

Several authors have pointed out that each type of building (homes, schools, office buildings) tends to have its own set of typical mold species. This is probably because each building type typically has its own characteristic “amplifiers” or sources and conditions, such as mattress dust and humid bathrooms in homes, leaky roofs and defective plumbing in schools, and poorly maintained HVAC systems in office buildings.

The mold counts found on the weather page of many newspapers have little to do with the indoor exposure to toxic mold spores. Outdoor molds are not normally a threat to human health. Many of them live on plant leaves or in forest litter, and are not found in great concentration except in ooutdoor manmade facilities like compost areas, dumps, and sawmills.

Sources of Information

the Aspergillus Web Site
“This site is designed to provide information on pathogenic Aspergilli for clinicians and scientific researchers. The site includes DNA sequence data, a comprehensive bibliographic database, laboratory protocols, treatment information and discussion groups. The Aspergillus Web Site is sponsored by Alza Corporation and Ortho Biotech Inc. and the sponsors have access to the Web Site address book–as do all other Aspergillus Web Site users. The European Science Foundation has also made a contribution to the maintenance of the site.”

Short Courses and Symposia

The Mid-Atlantic Environmental Health Resource Center has planned three courses this spring and summer in Pennsylvania, mainly for representatives of disaster response companies that deal with mold and moisture-related problems. They will be held April 10-11 (“Controlling Chronic Moisture and Microbial Problems in Buildings and Mechanical Systems”); April 12-13, “Damage Mitigation and Building Restoration for a Health Indoor Environment”; and 3 days in July (“Mold Remediation Worker/Supervisor”). MEHRC is at 3624 Market St., First Floor East, Philadelphia, PA 19104 (tel. 215/387-4096; fax 215/387-6321; http://www.mehrc.org).

The US EPA Region 8 and the University of Tulsa’s Center for Environmental Research and Technology (CERT) will be giving a short course in Denver, Mar. 8-9, 2000, entitled “Indoor Air Quality: Asthma and Allergen Control.” It will cover indoor air basics, public health issues, cleaning, remediation and indoor air solutions; the emphasis will not be on mold. Registration for people from the public sector is $190. Contact the University of Tulsa, Chemical Engineering Department, Attn: Indoor Air Program, 600 S. College Ave., Tulsa, OK 74104-3189 (918/631-3290; fax 918/631-3289 or 631-3268; http://www.utulsa.edu/IAQprogram).

The University of Tulsa will also give a longer course with a broader scope, for doctors and the medical community, in Dallas May 11-13. Announcements have not been sent out yet.


Fungi and Bacteria in Indoor Air Environments: Health Effects, Detection and Remediation. (Proceedings of the International Conference, Saratoga Springs, NY, Oct. 6-7, 1994). Editors: Eckardt Johanning and Chin S. Yang. Eastern New York Occupational Health Program, 1 CHP Plaza, Latham, NY 12110. 1995. 228 pp. This is the volume that includes the 7-page “Guidelines on Assessment and Remediation of Stachybotrys Atra in Indoor Environments.” It also includes “Legal Aspects of Indoor Air Quality,” by Guy Keith Vann.

Bioaerosols, Fungi and Mycotoxins: Health Effects, Assessment, Prevention and Control. Eckardt Johanning, ed. (Proceedings of the Third International Conference on Fungi, Mycotoxins and Bioaerosols, 1998, Saratoga Springs, NY) 638 pp. Available for $25.00 to participants (and $45 or 45 Euros to others, + $6 shipping). U.S. and Canada: order from Boyd Printing, 49 Sheridan Ave., Albany, NY 12210 (fax 518/436-7433). The last six papers, which are in a “Special Section” at the end, contain some material on assessment. “Learning from Stachybotrys Chartarum: How to Find Hidden Mold in Buildings,” by Claude Mainville et al. (see sidebar above), is an eminently readable narrative concerning a Montreal office building that had suffered water intrusion during the January 1998 ice storm. (He says, by the way, that the way to find hidden mold is to open up the structure.)

Bioaerosols: Assessment and Control. Janet Macher, ed. American Conference of Governmental Industrial Hygienists, 1999. [Full reference on p. 60 of the last issue.]

Building Mycology: Management of Decay and Health in Buildings, by Jagjit Singh. 326 pp. E & F Spon, An Imprint of Chapman & Hall, 1994. About $122. Most of the text has to do with mold problems in England, but there is one chapter that describes North American problems. Well illustrated with color photographs and photomicrographs, drawings of building structure, graphs, and ordinary photographs of buildings—and of “rothounds” searching for dry rot. Cost: about $122, from Preservation Resource Group in Rockville, MD (301/309-2222; fax 301/279-7885).

The Preservation Resource Group book catalog lists 10 books under the heading “Building Pathology,” including Building Mycology, Dampness in Buildings, and The Growing Fungus. The company also sells borate based wood preservatives to treat decayed wood. It serves the needs of the historic preservation community, and also of homeowners who want to decontaminate and rebuild moldy parts of their houses.

“A Search for Moisture Sources,” by Jeffrey E. Christian, p. 71-81 in Bugs, Mold & Rot II: Workshop Proceedings, Nov. 16-17, 1993. William B. Rose and Anton TenWolde, eds. Building Environment and Thermal Envelope Council of the National Institute of Building Sciences, Washington, DC. 1993. Every conceivable source of water in a house is identified and its output quantified. Example: In a typical new house, a concrete basement will release 6.4 liters of moisture per day.

Proceedings of the First NSF International Conference on Indoor Air Health: Impacts, Issues and Solutions. May 3-5, 1999, Denver. ISSN # 1523-6080. NSF International, 789 Dixboro Road, Ann Arbor, MI 48105.

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