So You Want To Know About Mould?

By John J. Rindy, MPH, CIE

Industrial Hygienist and Quality Assurance Manager

U.S. Micro-Solutions, Inc.

Adjunct Professor

Youngstown State University

www.ysu.edu

This page is intended to cover the most frequently asked questions about indoor mould. While you are encouraged to seek out an answer to your specific question, it is best to take the time to read all of the questions and answers below, to gain a better knowledge of indoor microorganisms and how they affect people.

Here are some quick answers to the biggest questions. . . .

Who are you and how do I know this information is reliable?

I have worked in environmental science and occupational health since the late 1980’s. Prior to that I worked for a clinical testing laboratory. I have an Associates in Business Management and a Bachelor of Science in Environmental Studies from Youngstown State University, and a Master of Public Health through the Northeast Ohio Universities Master of Public Health Program. In the past three years, I have been a part of various indoor air quality investigations for over 350 sites ranging from schools, to colleges and universities, high-rise office buildings, hospitals and clinics, commercial establishments, manufacturing facilities, retail and convenience stores, apartments and public housing, government buildings, warehouses, storage centers and private residences. I am also a professor of environmental science and health professions at a large state university in Ohio. I have attended national and international conferences on indoor air quality, industrial hygiene, bioaerosols, mycotoxins and fungi for nearly 15 years. I am also a Certified Indoor Environmentalist (CIE) with current credentials through the Indoor Air Quality Association (IAQA). I am a member of two local chapters of the American Industrial Hygiene Association (AIHA), a member and former board member of the Northern Ohio Air and Waste Management Association (A&WMA), and a member of the American Public Health Association (APHA). Bottom line. . . you don’t know if this information is reliable. . .but you are going to have to trust me on this.

Are mould, fungi, yeast, mildew and mushrooms all the same thing?

It is easier to say “YES” then to explain it here in detail. All of these are in the Kingdom of Fungi (fun – j eye). Slimy fungi are called yeasts, while moulds and mushrooms are more structural or “filamentous”. Mildew is not really anything and is just a generic word used to describe yeasts and moulds. As far as describing them, these organisms are more plant-like then anything else. Different fungi can reproduce sexually or asexually. They prefer to grow and thrive on dead plant and animal tissue. There are probably hundreds of thousands of different types of fungi in the world. Only a fraction of these have been isolated and identified.

What causes mould?

Water, food and spores. That’s all you need. Take away any one of these. . .no mould. I have never seen a building with a mould problem. It’s true. I have seen plenty of buildings with moisture problems that led to mould growth, but never a building with a mould problem.

What am I smelling when I smell that mouldy smell?

Fungi digest their food outside of their cell wall. They secrete digestive enzymes onto the surface they are living on, then draw up the nutrients into their cells. As the food digests (rotting wood or mouldy paper, or a damp mouldy basement or shower), gases are given off. It is sort of like an “external burp”. You can smell the mould digesting the thing it is growing on. These gases are called MVOCs or microbial volatile organic compounds. Most of these compounds are from the chemical families of alcohols and aldehydes. Remember that other processes and common chemicals can also produce these odors. The odor alone does not guarantee that mould is actively growing.

Is indoor mould making me sick?

As of the update of this website (June 15, 2004), no published paper by any professional journal or respected science association, university or government agency has definitively proven that indoor mould causes any of the non-specific symptoms occasionally associated with its presence. No scientific study has proven, statistically, that mould can cause headache, memory loss, concentration trouble, dizziness, trouble breathing, vision problems, muscle aches or other commonly noted symptoms.

What is the deal with mould?

Over the past 20 years, people all over the world have begun to question whether indoor moulds could be causing non-specific symptoms and general discomfort generally associated with occupying a specific building (sick building syndrome). The issues are three-fold (at least):

Is mould allergenic? Does mould produce allergies in some people? Indeed it can and this can cause problems for some folks.

Is mould toxic? No, mould is not toxic. Some moulds produce substances called mycotoxins. There is question whether or not these are toxic to humans in the small amount that is actually present indoors.

Is mould pathogenic? That is to say, “can it infect people and cause disease?” There is a section below on this subject.

What is this about toxic mould then?

Some moulds do produce poisons (I dislike the word toxin because most people do not really understand what a toxin is and the word is often misused by non-scientific types selling quack vitamins and other products falsely intended to remove “toxins” from your body). The reason they produce these poisons (mycotoxins) is simple; they have to fight with other mould for food. They release the substance as a defense mechanism to “claim their territory”. The amount of mycotoxins vary but most of these substances are present in such small amounts, it would take very sensitive tests in a professional laboratory to detect them. A certain type of mould may produce mycotoxins when growing on one thing, but not produce them when growing on another object. It is impossible to tell by looking at mould if it is producing or has produced mycotoxins.

What about mould and allergies or asthma?

There is plenty of medical evidence that mould causes allergic symptoms in some people. This can lead to asthma attacks in persons sensitive to mould, who also have a tendency toward asthma. But just because you are allergic to one type of mould does not mean that you are allergic to the mould on a wall in the basement or kitchen. Remember, there are over 100,000 types of moulds, no one has been shown or could be shown to be allergic to all of them. In fact, there are moulds from the same basic family that can cause two separate responses in the same person. For example, you may be allergic to Penicillin, an antibiotic made from Penicillium mould. On the other hand, you may enjoy and have no problems eating bleu cheese dressing or crumbled bleu cheese on your salad. Bleu cheese is also made from Penicillium, but it is made from a different species than the type used to make medicine, Penicillium roqueforte. This is actually my own personal example, I cannot take Penicillin but I have no problem with bleu cheese.

What part of the mould actually causes allergies?

In short, think of mould as a plant for a minute, I will give a very condensed answer to this question although not all fungi grow in this manner. The branches coming up from the bottom are called the hyphae (hi-fee). At the top of the hyphae there may be a structure like a fan or flower called a fruiting structure. At the end of these structures, spores or conidia can form (these are like the seeds). If the mould is growing in a windy area or a place subject to abrasive forces (people brushing up against it or walking close to it), the spores and hyphal fragments (which are microscopic particles – you cannot see a single hyphae or spore with your eye – you need a microscope to see them) can become airborne and breathed in. With nearly every breath you take, no matter where you are (home, school, work, church) you are probably breathing in a few, to a couple dozen mold spores or hyphal fragments. When someone with allergies breathes these in, if it is a mould they are allergic to, the body reacts by treating the particle as a foreign invader. It sends out an immune response that may be show up in the form of difficulty breathing, tightness in the chest, runny nose, watery eyes, sneezing or even some skin discomforts (if the mould is contacted with the skin).

Can mould (fungi) cause disease?

Absolutely. Have you ever has Athlete’s Feet? Then, you have been infected by a fungus. Fungi can cause other infections too, but usually in people with immune systems that are not strong (post surgical patients, cancer patients, organ transplant patients, AIDS patients or people on heavy doses of steroids). These infections are called opportunistic because the fungi are looking for just the right “opportunity” to cause disease. These infections are somewhat uncommon and not commonly associated with mouldy buildings. In fact they can occur in any building, including in convalescent areas of hospitals (these are called nosocomial infections). Very few fungi actually cause life-threatening infections in healthy humans. Two fungi that can be harmful to almost anyone include Histoplasma capsulatum and Crypotcoccus neoformans. Fortunately, both of these are also uncommon and usually only show up in buildings infested with rats, other rodents, bats and pigeons. The fungi are associated with their droppings and can make even healthy people, very sick.

Is “Black Mould” the worst type of mould?

The funny thing is, “black mould” is actually dark green. It’s true! Stachybotrys chartarum, misnamed “black mould” has more of a green sheen to it, but most folks see it as black. This is not the only molud that appears black. There are hundreds, possibly thousands of “black moulds” and none of these have been described by any reliable source as being “more dangerous” than any other. An early 1990s case of bleeding lung disease in small infants in the Cleveland, Ohio area, was originally attributed to the presence of Stachybotrys chartarum ( Stack-ee-bought-triss shar-tar-um) also called Stachybotrys atra. The Centers for Disease Control and Prevention (the CDC) later found flaws in the original study and dismissed the fact that this fungus causes bleeding lungs (pulmonary hemosiderosis). Stachybotrys or Stachy (Stack-ee) as it is called in the industry, grows in high water situations and mainly on cardboard, paper, magazines, drywall paper or any other cellulose-containing material that has been very wet for an extended period of time (usually a couple of weeks). It does not generally grow on basement walls, tiles, ceramics, concrete or plaster.

Is it worth it to test mould?

Sometimes yes. Sometimes no. Got a small spot of it in a house or commercial building? Go to the EPA website and read “A Brief Guide to Mold, Moisture and Your Home.” (link: http://www.epa.gov/iaq/molds/moldguide.html ) . If you have widespread mould growth and health complaints, you should consult an Indoor Environmental Professional (IEP) who carries a professional designation as a Certified Industrial Hygienist, Certified Indoor Environmentalist or similar designation. Also ask them about their experience, they should have dozens, if not hundreds of projects that they can tell you about. In general, a good indoor environmental scientist will cost between $70 and $125 per hour to hire. Lab samples, if they decide to collect any, will cost between $30 and $70 per sample. One sample is rarely enough to tell if there is a problem in a building.

Can tests tell if mould is causing symptoms in our building?

No. Indoor environmental professionals are absolutely not qualified to make a medical diagnosis at any time or in any way. Any attempts to do so should be greatly discounted and would never be supportable in a court of law.

What types of tests are there and what can they tell me?

An IEP is qualified to collect samples including air samples (impacted cultures or spore traps), swabs (a surface is swabbed with a special sterile swab), tape lift samples (an adhesive substance is used to remove a portion of an affected area), bulk samples (dust, chunks of insulation, chunks of carpet or wallboard), carpet samples (a special filter and vacuum system that can collect carpet dusts) and other types of samples as needed. Lab tests do not stand alone though. The IEP must conduct a thorough investigation of the property to present a complete picture of what is going on.

IEP can tell you is whether or not the “fungal ecology” in your building is representative of a “normal fungal ecology” for that type of structure. A good IEP takes into account roofing, carpeting, foot traffic, comparison of complaint and non-complaint areas, indoor air and outdoor air comparisons, outdoor air intakes and ventilation, heating and cooling systems, building comfort parameters (temperature, CO₂ and humidity), visible mould, possible hidden mould, plumbing problems and many other factors.

You can find a list of Certified Indoor Environmentalists at www.iaqa.org . You can find a Certified Industrial Hygienist in your area by contacting the American Industrial Hygiene Association through their website at www.aiha.org. It is, however, important to screen your prospective consultant to assure that they have a specialty in indoor air and moulds. Also assure that they are not affiliated with a clean-up or remediation company. This can be a conflict of interest, especially when the consultant refers a mould clean-up job to his parent company.

Can these tests measure my exposure to mould?

No. These tests cannot measure how much mould you are being, or have been exposed to. Some people are familiar with industrial hygiene monitoring where a worker wears a sampling pump for a whole shift. This is a way of measuring the amount of a chemical they are exposed to at work. This cannot be done with mould. All air samples are “area samples”. They measure the mould concentration in an area and cannot and should not be interpreted to measure exposure. There are currently no air sampling methods for mould that can truly measure personal exposure.

Does OSHA, EPA or any federal agency have any limits for mould in indoor air?

No. There is not and probably never will be a “mould standard.” This is because unlike occupational exposure to chemicals, individual reactions to mould are very different. For example, if you and I are both exposed to the metal “lead” at 200 micrograms per cubic meter of air during a days work, we are both going to get sick at about the same time. Lead is very toxic and 200 micrograms per cubic meter is above the OSHA permissible exposure level. Mould does not work like that. For example, I might work, with very few problems in a building that shows indoor spore levels of 20,000 spores per cubic meter of air (this is pretty high for an indoor environment). You might walk into the same building and immediately react with a runny nose, sneezing and watery eyes. You see, no two people react the same to mould, so it is difficult, if not impossible for OSHA or the EPA to come up with a “safe” versus “unsafe” level of indoor mould.

Of buildings you have investigated, is mould usually the problem?

No. While I have encountered many buildings with reduced air quality, not all were caused by mould. In fact, many investigations fail to prove any reduction in air quality. So is it all “in someone’s head?” Probably not. In many cases, particularly commercial operations, the underlying cause of many “symptoms” was simply dissatisfaction with the work environment. This can be due to mental stress, co-workers who are difficult to work with, workstations that are not designed properly and begin to cause non-specific bodily symptoms (ergonomic problems) and other environmental problems like poor lighting, too much sunlight at a work station, not enough sunlight at a work station, cold air, hot air, overly dry or overly humid indoor air and other aesthetic factors. Remember, we are at work for 8 hours a day, over time, these factors can manifest symptoms in many different ways.

Are there other factors that can cause building associated symptoms? (my soapbox)

I have mentioned some above but it is worth mentioning a few more. Few things are more frustrating than a homeowner who “wants” to hire me “to tell them that mould is causing the problem in their house”. Mould is easy to blame because most folks do not know a lot about it and it is an “easy target” so-to-speak. Then, upon arrival on-site, I see three cats, two shaggy dogs, a few parakeets, a poorly kept house and two parents who each smoke a pack-a-day of cigarettes. They then want me to “find out” why their children have allergies, asthma and all sorts of recurring upper respiratory ailments. Let common sense rule before calling in an indoor air consultant. If you have a residential or commercial dwelling with a water leak – fix it and fix it fast! Is smoking permitted in OR NEAR your building? Disallow it, permanently. Are you keeping the temperature at a reasonable level (see ASHRAE Standard 55)? Are you cleaning the place (this goes for homes as well as businesses)? Is the place comfortable to work and the workstations designed well? Are people wearing too much perfume, cologne or are they allowed to spray and use personal care products in the work area? Disallow it, permanently. Are those with complaints sitting near those who have dogs or cats? Animal allergen is very powerful and it is very adhesive. It sticks to clothes and can affect others. Finally, are you or your employees using indoor air complaints or amplifying them as part of a collective bargaining or union shop “wedge”. Nothing could frustrate or insult a professional scientist more than chasing down a problem that has been fabricated. I only add this because I have been the professional victim of this in the past. A professional scientist is not interested in investigating a claim that is unfounded or fabricated, no matter what the financial rewards might be. It wastes valuable time where the IEP could be helping another with a bonafide complaint.

Should I spray pure bleach on mould?

Absolutely not! Never spray pure bleach on anything. Bleach is a powerful oxidizer (you take vitamins as anti-oxidizers to prevent the breakdown of your body tissues). Bleach will oxidize your upper respiratory system and can probably do far more damage than any type of mould could ever do. You can use a 10% bleach solution (1 cup to a gallon of water – always add the bleach to the water, not the other way around). Wipe the surface and the floor areas around the surface with 10% bleach. Really though, the goal to any mould clean-up is to remove the mould-affected item, not to kill the mould. Remember, mould can still be allergenic even if it is dead. You have to remove the spores and hyphae to reduce the chance for exposure.

Can I get sued because someone got sick from mould in my building?

As you may have surmised from my resume, I am not an attorney and that question is best left to a qualified counselor. However, it is worthy to note, as far as I have heard, no case has been won, in a U.S. court, where the basis of the suit was non-specific health-related symptoms. Cite for example, the largest settlement in U.S. history related to mould, the Melinda Ballard case in Texas. Here, the plaintiff, Ms. Ballard, was originally awarded tens of millions of dollars (this has been contested and reduced now). Despite claims of her health problems and her husband’s loss of memory and other non-specific symptoms which she attributed to mould exposure, the judgment was not awarded on health issues, because there is no scientific proof that mould causes any of the symptoms claimed, other than allergies and asthma (and then, only in about 10% of the population, and further, each person’s sensitivity does not necessarily correspond to the mould growing in their home environment.) This judgment was more of a “failure to act” on the part of her insurance company (act to get the place cleaned up). I personally would not want the job of a counselor trying to prove a health-effects claim as the basis or core of a lawsuit. In my opinion (for what it is worth), until we have more data, it is an uphill, probably un-winnable battle.

Who is qualified to clean up mould-contaminated items and what is involved in mould clean-up?

Another loaded question. Since no legislation has been passed (except in the State of Texas) dealing with this, I can only offer my opinion. For widespread mould contamination, the area should be contained and placed under negative pressure for cleaning. Spore counts can soar 15 to 25 times the typical ambient level, during aggressive removal or demolition of mould-contaminated materials. Containment usually means blocking off air ducts (supply and return), surrounding the clean-up area with a wood frame and plastic (or placing the whole room or area under containment. A negative air machine (a large fan with a filtration unit) is used to draw air out of the space being cleaned. This way, as spores become loose (fugitive) they will not stray to other areas causing allergic or asthma problems. Materials are removed or treated according to their composition. Generally, porous items that are easily replaced (like drywall) should just be discarded. Semi-porous materials (like wood) can be cleaned by HEPA vacuum or damp scrubbing, but in many cases should simply be replaced, especially if they are no longer structurally sound. Non-porous items like countertops, concrete, masonry, tiles etc, can be cleaned with a common cleaner, appropriate for each surface. Many remediation contractors will try to sell you “mould-killing” fogs, sprays, liquids and the like. I do not sanction this because the exposure from these chemicals can be unpredictable (to the homeowner of employees working in that area). If you remove the water source, you will not need all of the fancy mould-preventers (anti-microbials). Without a water source, the mould will not come back. . .period! As far as certifications go, I suggest that you seek out a restoration contractor with more that 5 years experience in water damage and at least 3 years experience in mould restoration. Actual certifications to look for include those issued by the Institute for Inspection, Cleaning and Restoration Certification (IICRC), the Indoor air Quality Association (IAQA) or the American Indoor Air Quality Council (AIAQC). Other certifications exist as well, however, I am aware of these and find that most people who have attended these courses appear to be competent at mould remediation.

Can I hire you to do our building investigation?

Although we do field surveys, we are very selective about the sites that we will accept. Our (U.S. Micro-Solutions) accepting a project is highly dependent upon our schedules and the type of project involved. Most of our work is laboratory, research, writing papers and articles and teaching and educating others. In lieu of our working on your project, there are probably highly qualified IEPs in your area. Anyone in administration at my company can help you to locate someone who specializes in your specific challenge. Our office number is 877-US-MICRO or 877-876-4276. We can also check our schedules and evaluate your project to see if it is within our area of expertise.

What will a survey cost?

Survey costs depend widely upon the amount of time involved in the project. Charges are for time, travel, materials and laboratory services as needed. Most IEPs charge for the travel time to get to you, the time on-site, the time to drive back to their office and the time it takes to write your report (after all, they get paid by their company for all of that time – the company is in business to recover that cost and make money on that time). They may also charge for telephone or research time. Travel charges include tolls, parking plus a per mile charge. Laboratory charges are billed at the lab price plus a mark-up (unless your consulting company is also a laboratory). A one or two-story residence total survey cost generally falls between $800 and $2000. Commercial jobs vary even more greatly. I have done $400 commercial jobs and I have done $30,000 commercial jobs. Regardless of the type of job, you should secure a scope of work from the contractor to assure that you are going to get the product (service) that you desire. A scope of work defines exactly what the IEP will do, what you will receive, how much it will cost (at least approximately) and when you will receive the report.