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Are You Chemically Sensitive?

By HHI Staff

Are you sensitive to low levels of pollutants in the indoor environment? There are many people exhibiting symptoms at much lower pollution levels than the general population. This tells us that a safe level of exposure for one person is not safe for everyone. In reality, we all have a different degree of tolerability because we all have a unique physical body and a unique metabolism. Some individuals can smoke several packs of cigarettes a day and live disease-free for 80 years, but there are others who are negatively affected by very minor exposures to second-hand tobacco smoke. Most of us fall somewhere between these extremes of extraordinary tolerance and extreme hypersensitivity. Yet, we all may be bothered by the very same pollutants that affect hypersensitive people—but only after a longer period of exposure to a higher concentration.


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Hypersensitive people may act as early warning signs to the general population in the same way canaries warned coal miners of polluted air in the mines. Canaries are more susceptible than most people to air pollution and they were taken into the mines to help predict when the air reached dangerously contaminated levels. When the birds stopped singing and died, the miners knew it was time to seek fresh air. Today’s canaries may be the individuals who are more susceptible than the population at large. The rest of us should become aware of what bothers them because, the odds are, similar things could bother us as well. Their symptoms just show up immediately while ours may not manifest themselves for years.


Many people seem to be exhibiting more symptoms related to their environment than in the past. For example, allergies are much more common today than just 50 years ago, and sensitivities to formaldehyde and other VOCs are increasingly being recognized. This is likely related to the fact that the food we eat, the water we drink, and the air we breathe is totally different than the food, water, and air to which human beings have adapted over time. It seems our bodies are having difficulty adapting to an environment that is radically different from any other environment in human history. Our ability to change our surroundings has apparently outstripped our genetic ability to adapt to those changes.


Two or three generations of eating prepared foods, processed flour, and food additives have resulted in subtle changes to our bodies. Sugar is no longer an occasional treat, it is often a daily staple. Manufactured foods abound—and they have less nutritional value than the whole, 'real' foods they have replaced. According to one estimate, the average individual consumes at least one gallon of fungicides, bleaches, dyes, antibiotics, preservatives, moisturizers, and emulsifiers per year [Andrew Nikiforuk and Barbara Binczyk, “The Pariah Syndrome,” Harrowsmith (U.S.) (August/September 1982): 51-61].  As a result of decades of eating less-nutritious foods and food additives, it seems our systems no longer have the stamina to resist the assaults of environmental pollutants. The many negative health effects of our modern diet and lifestyle have been documented by Charles T. McGee in How to Survive Modern Technology.


The sad truth is that the air we breathe every day of our lives, both indoors and outdoors, is contaminated with chemicals that our genetic history has not prepared us for. This means our lungs must continually deal with an unnatural pollutant burden. This stress is occurring every minute of every day and it means our bodies have less ability to handle an acute pollution emergency. This constant exposure has resulted in people having less resiliency than they had in the past—and more illness. Much of this illness may be attributable to the toxic, allergenic, and carcinogenic materials we use to build houses.

Subliminal exposure

We are all exposed to a certain amount of air pollution that can be referred to as the background level, or subliminal exposure. Subliminal exposure to air pollutants can effect people in a real, but subtle, way. According to one scientist, “The greatest danger of pollution may well be that we shall tolerate levels of it so low as to have no acute nuisance value, but sufficiently high, nevertheless, to cause delayed pathological effects...” [Rene Dubos, “Adapting to Pollution,” Scientist and Citizen 10 (January/February 1968): 1-8]. We tend to become accustomed to the constant level of pollution around us because the effects are not suddenly devastating then, in later life, when the years of subtle exposure have contributed to chronic bronchitis, heart disease, or cancer, we have no idea why we are sick.


Pollutants can affect life in many ways, some of which are not immediately detrimental to health. Every one of our bodies contains pollutants not needed for growth and development. This is known as our pollutant burden, and it is often the result of subliminal exposure to chemicals. For a large proportion of us there is enough pollution in our system to cause measurable, physiological changes. For many people, these changes have no apparent significance, but for some they can be described as sentinels of disease. While disease itself may not be present, the groundwork is being laid. A smaller percentage of us have pollutant burdens high enough to cause an illness of some type, and for a few of us, the levels are fatal.


The important thing for us all to realize is that we are subliminally exposed to chemicals, and a high percentage of society is already being subtly affected. Unfortunately, for many people, the results won’t manifest themselves for decades. For others, the effect is immediately devastating.

Symptoms and diseases

The symptoms and diseases that can be caused by indoor air pollution are many and varied. Symptoms of Legionnaires’ disease include pneumonia, cough, fatigue, fever, muscle aches, nausea, etc. It can also result in death. Radon and asbestos exposure can be fatal as well. While death is certainly the ultimate symptom anyone can experience, there is increasing concern over the many other “lesser” symptoms that are much more common.


The pollutants typically found in our homes can cause symptoms such as lack of coordination, dizziness, fatigue, nervousness, headaches, joint and muscle pain, abdominal pain, etc. According to the World Health Organization, the following are common symptoms of sick building syndrome: Irritation of eyes, nose and throat; dry mucous membranes and skin; erythema; mental fatigue; headache; airway infections; cough; hoarseness of voice; wheezing; unspecified hyper-reactivity; nausea; and dizziness.


Many people are concerned about the carcinogens found in houses, but are less concerned about other indoor pollutants. It is sometimes assumed that if a material doesn’t cause cancer, then it must be safe. Unfortunately, some indoor pollutants are teratogenic, meaning they can result in birth defects such as deformities or serious malformations. Those that are fetotoxic can result in death to unborn children. Others may cause chromosomal damage that will show up in future generations. Heart disease and damage to the immune system are other possible common negative effects of indoor air pollutants. The fungus Stachybotrys atra is highly toxigenic, being associated with central nervous system complaints, eye and skin irritation, upper and lower respiratory tract problems, and chronic fatigue. Stachybotrys atra has been found in some Cleveland homes, where it is suspected of resulting in spontaneous bleeding in the lungs of infants.


People sensitized by chemicals such as formaldehyde often report a variety of reactions to other VOCs in the air. Some of these people are so sensitive to the synthetic modern materials in their environment they must live in very restricted surroundings to remain symptom free.

Non-specific symptoms

Non-specific symptoms are those everyday complaints we all have from time to time that seem to have no particular cause. In actuality, they could easily be caused by indoor air pollution. Possible symptoms include headache, swelling, abdominal discomfort, drowsiness, ringing in ears, malaise, blurred vision, and fatigue.


An irritant is a substance that abnormally stimulates a part of the body. Examples include the inflammatory response of the skin when exposed to a solvent-containing paint, or the inflammatory response of the sinuses to various VOCs. Many airborne gases and particulates can cause skin irritation resulting in acne and contact dermatitis.

Neurological effects

The brain is one of the most sensitive organs in the body. So it should come as no surprise that many solvents and VOCs are capable of causing a wide range of neurological symptoms such as confusion, loss of memory, dizziness, depression, anxiety, mood swings, hallucinations, apathy, lethargy, and insomnia. Neurotoxicity is often a primary health effect associated with pesticide use, and it is of particular concern because apparently the brain cannot regenerate itself, thus neurological damage can be permanent. 


Some chemicals can damage, or change, the DNA residing inside our cells. This is very serious business because our DNA is what defines us—both as individuals and as humans. When this happens, most of the altered cells die—but a few survive to replicate themselves. These altered cells are different from the cells we were born with—they are mutations. If the cells affected are reproductive cells (sperm or egg), we can pass the mutation on to our children—with unknown consequences. Very few chemicals have been studied for mutagenicity. Some experts believe that, under the right conditions, most carcinogens can also be mutagenic. Vinyl chloride has been associated with an increase in chromosomal abnormalities. 

Birth defects

Chemicals that cause birth defects are called teratogens. The drug thalidomide and grain alcohol are notable examples. Both have a negative effect on the developing fetus while it is growing inside the womb. Many solvents and heavy metals, such as lead, are considered suspected teratogens.


In one study, women who were exposed to polychlorinated biphenyls (PCBs) had children with lowered I.Q., lowered reading comprehension, and problems related to memory and attention. Another study found that women who were exposed to chemicals during their pregnancy were not only more likely to have children with birth defects, but fetal death was also more likely.


Asbestos, radon, and wood smoke are carcinogenic. Formaldehyde is carcinogenic in animals and in humans. With carcinogens, there is no level that is considered risk-free, but less exposure definitely means less risk. Some materials are not necessarily cancer causing, but are cancer promoting. Promoting agents work in conjunction with other materials to cause cancer.


A sensitizer is substance capable of enhancing the body’s response to that substance. In other words, it will cause the body to become more sensitive to lower levels of exposure. Toluene diisocyanate (TDI), which is used to make some foam insulations, is a known sensitizer, as is formaldehyde.

Allergies and Asthma

An allergy is a well-characterized immune response involving antibodies and antigens. At least 60 million Americans, about 1 in 4, have allergies. Eight-million school and work days are lost annually due to allergies, and we spend over $600 million every year to get relief.


Moisture problems in houses can lead to excessive mold or mildew growth, or increased populations of dust mites, thus aggravating allergies. A study of Seattle school children found that asthma symptoms (such as wheezing) were often associated with household water damage—something that often leads to mold or microbial growth—and cigarette smoke. Surprising to many people, cockroach allergy affects 10-15 million Americans. Allergies have also been recorded to various types of wood, paints, and furnishings. One study found that 15-20% of asthma cases were attributable to exposure to chemicals in the workplace. Many of these same chemicals can be found in low concentrations in houses.


Poorly designed or constructed heating/cooling systems can generate and distribute allergenic material around the living space, while well-designed systems can help to reduce the concentration of allergens in a house.


Asthma is most likely a group of diseases that result in an inflammation of the bronchi (air passages into the lungs) and spasms in the muscles surrounding them. Asthmatics typically have inflamed bronchi, even when they’re not in the midst of an attack. When they are having an attack, they generally feel short of breath, have a constriction in their chest, and begin wheezing. Other common symptoms are fatigue and coughing. In a worse-case scenario, death results. There are now at least 15 million Americans with asthma, of whom 5 million are under the age of 18. The annual death toll is 5,500. Furthermore, the U.S. Centers for Disease Control has reported that, during the past 13 years, the number of children with asthma has doubled. And, according to the American College of Emergency Physicians, asthma causes 9 million lost work days each year.


Asthmatics often react to common indoor pollutants such as dust mites, mold spores, cigarette smoke, house dust, aerosol sprays, and wood-burning stoves. In addition, VOCs released by adhesives, cabinetry, and paints can trigger an asthmatic attack.


Physicians specializing in allergy and asthma treatment often belong to the American Academy of Allergy, Asthma, and Immunology (AAAAI) or the American College of Allergy, Asthma, and Immunology (ACAAI). Also, the American Academy of Otolaryngic Allergy (AAOA) has members who specialize in ear, sinus, and throat allergies. In addition, there are national patient support groups such as Asthma and Allergy Network, Mothers of Asthmatics, Inc. (AAN/MA) and Asthma and Allergy Foundation of America (AAFA) that have a number of fact sheets and brochures available.


Multiple chemical sensitivity (MCS)


Multiple chemical sensitivity (MCS) has been known by a variety of names. Total-Allergy Syndrome, Chemical Hypersensitivity Syndrome, Environmental Illness, Ecological Illness, and Immune-System Disregulation are all names for the same condition. MCS involves an increased sensitivity to a wide variety of chemicals encountered daily. These substances are often petrochemicals or their derivatives. The reactions and symptoms do not fit into the traditional allergist’s definition, so they are usually not considered true allergies. Reactions can occur to automobile and diesel exhaust gases, artificial fragrances, synthetic fabrics, plastics, food additives, printers ink, etc. In short, practically everything in our modern, manufactured environment can cause problems. It’s been reported that “approximately 15% of the U.S. population have an increased allergic sensitivity to chemicals found in household products.” The Labor Institute has found enough interest in MCS to publish a 95-page booklet, Multiple Chemical Sensitivities at Work, to educate working people.


Some people are of the opinion that healthy houses are only necessary for very sensitive people, such as those with MCS. That’s like saying food is only necessary for the starving. We all need healthy houses, it’s just that those with MCS have a more critical need. Actually, most people with MCS were not born with the condition—many acquired it as a result of living in an unhealthy environment.


There are a number of factors that can predispose a particular individual to developing MCS. For example, some people are more susceptible because of heredity—they just happen to have genes that make them more likely to get ill. Some people develop MCS after a severe viral, bacterial, or fungal (e.g., Candida) infection. Others can apparently trace their illness to a single heavy chemical exposure or to a smaller long-term chemical exposure. Increased stress also plays a role—either emotional, physical, positive or negative. And poor nutrition has also been implicated. In many cases, the onset of illness is related to a combination of these factors. A case study will help illustrate this condition.

MCS case study

As a girl LR grew up in a large metropolitan area where she experienced symptoms of depression, insomnia, malaise, and nervousness. Many of these symptoms got worse as she grew older but they were not nearly so severe when she was in a rural area. Whenever she went shopping with her family, she became weak and had to sit down often to catch her breath. She became increasingly uncomfortable around such things as cigarette smoke and exhaust gases. In college, she found her health was markedly better in an older dormitory. When she moved into a newly constructed apartment, her health deteriorated rapidly. An art major, her thinking got fuzzy in oil painting and watercolor classes.


After marriage, she and her husband moved into a new apartment where new building materials caused burning and watery eyes as well as severe mood swings. Her husband was unaffected, but LR’s health steadily deteriorated until, after relocating several times, she and her husband moved into an older home in a rural area. Here she felt better than she had in years—although her health was still poor. They later purchased another house, again away from the city, that needed some major renovating. After several years of construction work on the house, running a part time furniture-refinishing business, and providing freelance art work, LR’s health collapsed.


She could hardly walk because of back and muscle pain. Her lungs ached. Her stomach was so irritated she could barely eat. Her vision was blurred. Her sinuses were inflamed. Her gums were sore and bleeding. She hallucinated whenever she was able to sleep. She suffered chronic bladder and vaginal yeast infections. Practically every system in her body was affected.


She tracked down what she thought was the culprit—formaldehyde. It was emitted from the new bedroom furniture, new kitchen cabinets, new draperies, and new bed linens. When the bedroom was cleared of the suspected causes, her health seemed a little better. By now, the house had been completely rebuilt and, as planned, put up for sale. The idea was to make enough profit to build a new house and get out from under a mortgage payment. After the sale, the couple began looking for land to build on, and temporarily moved into a rental house that was old enough to have no new formaldehyde sources. That summer, LR’s health seemed much better, however during the winter it rapidly deteriorated. Whenever the natural-gas furnace ran, LR felt horrible. She assumed insecticides had been sprayed into the ductwork, causing her problems. The fresh paint was also suspected.


As they continued to search for a building site, the couple moved into another rental they hoped would be healthier. This place was also old enough to not have any new formaldehyde sources. It seemed like a nice spot, with a woods and small stream on one side. However, once she got settled, LR’s health steadily deteriorated. The house had natural-gas heat, was next door to a gasoline station, and across from a doughnut shop where truckers let their diesel engines idle while they drank coffee. It was here that she saw MCS mentioned on a television news program. Suddenly all of her symptoms fell into a pattern. It was now obvious that her current residence was one of the worst places she could have chosen to live. She now realized that she was reacting to not only formaldehyde, but to petrochemicals in general, and a wide variety of their derivatives. Every cleaning product under the sink was a problem, as were synthetic fabrics. Her wardrobe had to go. The upholstered furniture had to go. An unscented soap and detergent had to be found. Most importantly, a healthy house had to be built because it was obvious she was reacting to such things as wall paneling, paints, and the natural-gas furnace.


Several years later, LR has regained a great deal of her health. Her house in the country is as pollution-free as possible, but she is very careful about trips into town because of the many possible chemical exposures. She remains so sensitive that upon returning from town, she must shower and launder her clothes to remove any traces of exhaust gases, cigarette smoke, and synthetic fragrances. Her artwork is now limited to using a metal mechanical pencil on 100%-cotton-rag paper inside a special box with a built-in activated-carbon air filter. One of her biggest regrets is that no one knew about MCS when she was in elementary school. She could then have avoided many of the everyday exposures that seemed so safe. Perhaps then she would not have lost so much of her tolerance.

Implications of MCS

People with MCS typically exhibit symptoms to extremely low levels of pollution—levels that are often assumed to be safe. They sometimes react to concentrations of pollutants so low they cannot be measured by conventional instruments. Because of the experiences of individuals like LR, it’s becoming obvious that people can be much more sensitive to indoor pollution than was once commonly believed. It is a sobering thought to realize that devastating health effects can occur to the indoor-pollution levels we are all exposed to every day.


After removing many sources of indoor air pollution from their homes, sensitive individuals often see an improvement in their health. For many of the people with MCS, this is sometimes done as a matter of immediate survival. In a Canadian study, 23 of 29 respondents reported daily symptoms prior to making healthy modifications to their house, and after the modifications were made, only 3 reported daily symptoms. 


In many situations, as the indoor environment is cleaned up, other members of the family begin to see improvement in their health, as minor symptoms go away. Suddenly, they realize that they were also reacting to poor indoor air quality, but to a somewhat lesser degree. The implication for society at large is that we may all be affected by the small concentrations of pollutants that surround us. It is just that those with MCS react sooner.


(Note: The views expressed in this article are those of the author, and do not necessarily represent those of The Healthy House Institute, LLC.)


(This article is from the archives of the original Healthy House Institute, and the information was believed accurate at the time of writing.)


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Are You Chemically Sensitive?:  Created on March 8th, 2009.  Last Modified on December 18th, 2013


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