An Introduction to Multiple Chemical Sensitivity and Electrical Sensitivity


An Introduction to Multiple Chemical Sensitivity and Electrical Sensitivity

Articles Multiple Chemical Sensitivity Articles

by Pamela Reed Gibson, Ph.D.
James Madison University




Originally part of an article named ‘Understanding & Accommodating People with Multiple Chemical Sensitivity in Independent Living’.


In multiple chemical sensitivity (MCS) a person develops markedly negative reactions to everyday chemical exposures. These include exposures to pesticides in buildings, in gardens, on our food, and on pets; chemical cleaners; petrochemical heating systems; paints; perfumes; industrial emissions; and a myriad of others. We have been conditioned to think of these exposures as being “normal” and inconsequential, but for a growing portion of the population they are not. The condition of MCS develops in two stages induction and triggering. In induction some contact with chemicals causes the person to sensitize to at least one class of chemicals. This contact can be one large chemical exposure such as a chemical spill or a pesticide application, or it can be a low-level, ongoing exposure such as one might experience in a workplace with poor ventilation combined with copy fumes, perfume, and chemical cleaners. After induction the person develops sensitivity to the chemical that was involved in the exposure and to other related chemicals. Thereafter the person will respond with symptoms when exposed to any of this class of chemicals. This is called “triggering.” The sensitivities developed are usually more or less permanent, although the kind and intensity of reactions may vary. In what is called the “spreading phenomenon” the sensitivities tend to spread over time to other related chemicals and also to other classes of chemicals. The primary way to avoid reactions once sensitivities have developed is to avoid contact with the triggers. With each new sensitivity this becomes more difficult and the person’s access becomes more limited. For this reason one of the major goals in helping people with MCS is to try to limit the spreading by reducing chemical exposures in order to preserve what tolerance the person still has. Unfortunately it is not unusual for people developing MCS to continue to expose themselves to chemicals because at first they do not link their reactions to chemical exposures and/or do not know that repeated exposures can cause a worsening or spreading of their sensitivities.

Although less is known about electrical sensitivities (ES), people who experience them report that they develop in much the same way as MCS. An initiating exposure to an electrical field causes the sensitization, which then sets the person up to experience negative health effects in response to any future contact with electrical fields or radiation. Avoidance of electrical fields is then necessary in order to avoid debilitating health reactions.

What Kinds of Negative Health Reactions Occur?

MCS symptoms can affect any organ system including respiratory, digestive, neurological, endocrine, urinary, cardiovascular, or immune. The health problems experienced from each trigger vary from person to person, but tend to be stable for each person with each trigger. This means that one person may have a constellation of symptoms from petrochemical exposure such as vehicle exhaust that includes headache, confusion, dizziness, and nausea. This constellation occurs each time that person has a petrochemical exposure. There are many symptoms that people can experience from chemical exposure. The five most common symptoms in my research were tiredness/lethargy, difficulty concentrating, muscle aches, memory difficulties, and long-term fatigue. This suggests overlap with chronic fatigue syndrome. Other commonly reported symptoms include digestive problems, joint pain, headache, irritability, tenseness, spacey feelings, insomnia, depression, difficulty making decisions, pressure in the head, rhinitis, sleepiness, eye irritation, coordination problems, dizziness, slow response, chest pain, tingling fingers and toes, nausea, rashes, and hives. Symptoms from electrical sensitivities may include loss of muscle control, noise sensitivity, and other neurological problems.

The health problems triggered by chemicals in people with MCS vary from mild to life threatening, and for some pose very alarming situations. For example one woman in my study gets dangerous blood clots from chemical exposures. An environmental physician described to me a patient whose heart stops in public if she is exposed to chemicals. She has to have someone start it again.

Which Chemicals Cause the Most Problems?

In my research, respondents rated pesticides, formaldehyde, fresh paint, new carpets, diesel exhaust, perfumes, and air fresheners as being the most troublesome chemical exposures. This is congruent with other studies. Other triggers that are rated as being very problematic in various studies include tobacco smoke, fresh asphalt, moth balls, nail polish and remover, phenol, fabric softener, furniture polish, dry cleaning chemicals, hair spray, new vinyl plastic, chlorine bleach, auto exhaust, laundry detergent, natural gas, shampoos and conditioners, and newsprint.

It is also common for people to suffer from inhalant allergies to pollens and molds, or from food allergies. These problems further impair people’s functioning. In addition, some people’s lives are complicated by sensitivities to electromagnetic frequencies (EMFs), emitted by high-tension wires, transmitters, and other large sources of electricity as well as electrical appliances and other “small” sources found in the home. Although electrical sensitivity is less understood and accepted than MCS, there are some studies now that show that EMFs can alter the permeability of neurons, thereby affecting the levels and circulation of brain chemicals (neurotransmitters). In a number of these studies, EMFs also have been linked to cancer (particularly in children) (Pinsky 1995). I have seen a person with EMF sensitivity lose the ability to walk within seconds of exposure to fluorescent lighting. One moment she was walking fine and the next she appeared to have cerebral palsy simply from entering a building with this type of lighting.


Are These Reactions to Chemicals a New Medical Condition?

Although MCS still is not officially recognized by the medical establishment in the U.S., illness reactions from chemicals, particularly petrochemicals, are not new. Theron Randolph, M.D., thought to be the “Father of Environmental Medicine” was studying allergic reactions to petrochemicals in the l950s, and called this problem “The Petrochemical Problem.” As in the case of most visionaries, he was punished rather than rewarded for his work. He was fired from the University of Chicago School of Medicine for being a “pernicious influence upon students.” Randolph’s book An Alternative Approach to Allergies, written with Ralph Moss, describes his early work, his theories, and the basic tenets of Environmental Medicine. Claudia Miller (l996) believes that we need a paradigm shift in medicine that will take us to an understanding that toxicants are causes of not only MCS, but of a host of other illnesses and disabilities. She believes that this shift in understanding is so substantial as to be comparable to the shift that occurred that ushered in the germ theory of disease. But very little training in toxicology is offered to medical students, and this shift will require a tremendous change in the way that conventional medicine currently understands illness.


Exactly how do chemical exposures alter the body so that the person develops illness reactions to subsequent exposures? Although no one knows for certain, most researchers and physicians who seriously consider the problem believe that chemical exposure is to blame. The following are some of the major theories on exactly how chemical exposures alter the body.

Limbic Kindling/Neural Sensitization

A number of researchers believe that the phenomenon of kindling is involved in the development of MCS as follows: A nerve cell can be isolated and placed in a petri dish and then stimulated either with chemicals or electricity at a level that does not cause it to fire. But if the cell is stimulated repeatedly, it will eventually fire at a level of stimulation below that which would usually be required. In other words it is possible to “kindle” neurological tissue to respond at lower levels of stimulation simply by subjecting it to repeated exposures. Some researchers believe that some people have “kindled” their olfactory system to low levels of chemicals. The olfactory nerve which transmits the sense of smell runs from the nose and connects to the limbic system, the old animal brain that is involved in eating, mood, motivation, and all basic survival functions. Kindling through this nerve or other pathways could render the person sensitive to and affected neurologically by common everyday chemical exposures. Kindling is one of the most respected theories of how the sensitivities develop. Proponents of this theory include Claudia Miller, Iris Bell, and others.

Neurogenic Inflammation

William Meggs has offered another respected theory of how MCS develops that involves the respiratory system. He sees MCS developing much like Reactive Airway Dysfunction (RADS) or Reactive Upper Airway Dysfunction (RUDS) where cells in the airway become damaged from irritants and then generate inflammation. Through neurological connections with other parts of the body (called neurogenic switching) reactions develop in other areas of the body. That is, inflammation at one site induces inflammation at other sites via communication of nerves between the sites. Patients with MCS do have nasal abnormalities upon examination that support this theory (Meggs & Cleveland, 1993).

Other Theories

Other theories on the cause of MCS involve depleted enzyme systems. We know, for example, that particular pesticides are designed specifically to damage enzymes. The organophosphate pesticides (nerve poisons that were used widely in World War II as chemical warfare agents) knock out acetylcholinesterase needed to break down the neurotransmitter acetylcholine. When too much acetylcholine builds up between the nerve cells bugs die of convulsions. Unfortunately, the human nervous system contains many of the same neurochemicals as bugs, including acetylcholinesterase. People can suffer a number of severe problems from cholinesterase poisoning including nausea, vomiting, abdominal cramps, frequent and/or involuntary defecation and urination, wheezing, visual disturbance, weakness, fatigue, and muscle cramping or twitching. People can suffer delayed neurological damage that may include disturbances in sensory experience, motor function, speech, sleep, and emotional stability (Sherman, l995). Some people have also developed MCS following an organo-phosphate pesticide exposure. The mechanism of how organophosphate exposure causes chemical sensitivities is unclear, but probably involves residual brain damage of some sort.

Albert Donnay (1999) of MCS Referral and Resources has proposed that carbon monoxide exposure is a cause of MCS. There are historical descriptions of ill health that resemble MCS. This theory has prompted some physicians to experiment with oxygen treatments, which are useful in acute carbon monoxide poisoning, in patients with MCS.

A large number of chemicals, particularly solvents, are known to cause neurological damage. Painter’s syndrome is a condition that afflicts old painters who have a long history of exposure to paints and solvents. Neurological examinations of workers exposed to solvents reveal a variety of neurological abnormalities including problems with memory, attention and learning, as well as psychological symptoms. Lisa Morrow at the University of Pittsburgh and colleagues have published a number of studies in this area (Morrow et al., l990). Exposures to solvents have also preceded the development of MCS in some people.

Because the problem of electrical sensitivities has not been researched as much as MCS, theories on how it develops are lacking. It has also received less attention from writers and health practitioners.


The earliest estimation of how many people have MCS came from the National Academy of Sciences, which suggested that 15% of the population has sensitivities to common chemicals. Meggs and colleagues (l996) did a household population study and found that about one third of the population reported having sensitivities to chemicals. Chemical sensitivity affected persons of all ages, incomes, races, and educational levels. A little under 4% reported becoming ill every day from sensitivities. Two state health department studies have found similar results. In New Mexico, 16% of people reported being sensitive to chemicals, 2% had been diagnosed as having MCS, and sensitivities had caused 2% to lose a job or career. In California, almost 16% of adults were chemically sensitive and 6.3% had been diagnosed with MCS or environmental illness (Kreutzer, l999). If Meggs and colleagues are correct that 4% of the U.S. population is becoming ill every day from chemicals, this means that over 11 million people have moderate to severe MCS. MCS currently is not included in disability databases and will add substantially to the commonly cited figures of 43 to 48 million Americans with disabilities (NIDRR, l999).

Consumer and volunteer samples to date are all approximately 80% women. But, population studies such as the Meggs study find a smaller majority for women with about a quarter of men and over a third of women reporting illness from chemicals. We don’t really understand why more women than men may be affected, but there are several suggestions.

Women are more susceptible to auto-antibody and autoimmune illness and chemicals induce auto-antibodies. Women have less of an enzyme that detoxifies both alcohol and chemicals called alcohol dehydrogenase (Freeza et al, l990). Women are also smaller on average than men, have a higher respiration rate, and may be more vulnerable to hormone-disrupting chemicals (many toxics are estrogen disrupters.)

MCS is not limited to North America. Researchers have identified chemical sensitivity in several Northern European countries and in Greece (Ashford et al., l995).

Electrical sensitivities were addressed by the California Department of Health Services in the l998 California Adult Tobacco Survey and found to affect 3.3% of 2,072 adults surveyed (Levallois et al., 2000). But because this research was conducted via telephone, and people with electrical sensitivities often cannot use the telephone, it probably underestimates the numbers. Even so, the 3.3% extrapolates to 8 million Americans having ES.


Our cultural response to MCS has been almost entirely negative. People with this primarily invisible disability have been ignored, de-legitimized, dropped as friends, discriminated against in the workplace, fired from their jobs, and excluded from housing and medical care. Although there are some agencies that either recognize MCS or are attempting to incorporate it to some extent into their programs, for the most part the problem has been ignored. There has been no concerted attempt on the part of the medical community to learn about MCS. Although practitioners of environmental medicine see Theron Randolph as a mentor and deal primarily with MCS patients in their practices, they too suffer discrimination from the greater medical community because of this.

My framework for understanding MCS after nine years of research is this: MCS is an illness that is caused by industrialism, it is an indictment of industrial culture because it directly points to chemicals as a cause of disability, and it is totally incongruent with industrial culture. We are a culture that does “risk assessment” of each of our chemicals allowing a certain number of people to get sick or die from exposure to each chemical. While the EPA continues to compile lists of cancer causing agents, the field of health psychology continues to look for the “cancer personality” that supposedly renders some persons more psychologically prone to the development of cancer. We are experts at ignoring the obvious. While babies on the U.S. – Mexico border are born without brains, our industries continue to dump wastes into the air and water of that geographic region. Our institutions are created out of the same industrial paradigm that allows this contamination, and are therefore not only not positioned to respond in any constructive way, but are in many cases set up to deny and distort the reality of chemical-induced disability. This cultural set-up makes for personal struggles in a number of venues.


  • Understand the person’s need to meet in a very clean environment. Try to provide a setting free of fresh paint, pesticides, smoke, perfume, forced air petrochemical heat, chemical cleaners, and other toxics. Ask the person exactly what incitants she or he needs to avoid. As an accommodation, it may be necessary to speak by phone or go to the person’s home if getting to the center and surviving the environment there will be a hardship. If you go to the home of a person with MCS please follow any procedures requested by the person regarding what to avoid on your person, despite how odd the request might sound to you. The person might request no fragrance or hair spray, no freshly dry-cleaned clothes, no mothball fumes on clothes, no exposure to cigarette smoke that can be carried on clothes, or some other procedure to avoid what we call secondary exposures. Your clothing and hair pick up smoke, perfume, and other chemicals when you encounter them, and someone who is extremely sensitive can react to you because you are carrying these chemical fumes.
  • Understand that if the person has electrical sensitivities, he or she will have problems with a number of devices that are probably in your agency including battery re-chargers, oxygen concentrators, air filters, any electrical monitoring equipment, fluorescent lighting, and computers. You may have to turn off lights and unplug some equipment in order for these people to have access to your facility.
  • Provide an accepting and supporting attitude. By the time the person makes it to your agency, he or she has endured enough rejection for a lifetime. Try to eliminate any attitude you might have about MCS not being a ‘real’ disability. (This is usually fairly easy once you hear about the person’s life experiences.)
  • Learn as much as you can about MCS and what people with MCS say about having it. They are the best source of information. The rest of this book is devoted to helping you understand their personal struggles with this disability.


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