Multiple Chemical Sensitivity: Inside the World of Environmental Illness

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To avoid the chemicals found in conventional detergents that can trigger MCS symptoms, switch to chemical-free biodegradable brands.

(Correction: In the print version of this article published in Vitality’s Winter 2021 issue, it was incorrectly stated that Covid vaccines contain heavy metals. However, this is not true. It is only the flu vaccine that contains aluminum and mercury.)

What has happened in the area of Multiple Chemical Sensitivity (MCS) over the past two decades? A lot, and most of it is good. However, for those whose lives were ruined by toxic chemicals, finding help still remains a challenge, and restoring the health of their damaged central nervous systems remains problematic and slow.

Thankfully, what has become less of a challenge is finding safer nontoxic environments that don’t trigger an extreme reaction in sensitive individuals. Most hotels now use unscented products and offer organic and even gluten-free food options. Public awareness of the problem has increased as has accommodation for the afflicted.

For example, you are no longer considered a nutcase if you identify yourself as sensitive to scents. Best of all, the availability of nontoxic choices in groceries, clothing, toiletries, laundry detergent, building materials, bedding, furniture, carpets, and more has increased. It’s not perfect, but as a former MCS patient I can say that I’m far less likely to come in contact with food, drink, or fragrances that knock me over.

Symptoms of Multiple Chemical Sensitivity

MCS is a family of diseases, the best-known of which are Fibromyalgia/Chronic Fatigue Syndrome, Gulf War Syndrome, and Cacosmia (the MCS variant in which people lose all tolerance for scents, toxic or otherwise). Common symptoms include acute intolerance to light and noise and chemical and natural smells of all kinds, extreme fatigue, muscle pain, swollen joints, muscle weakness, shortness of breath evolving frequently into asthma, anemia, chronic urinary tract infections, nausea, diarrhea, migraines lasting days, tingling in hands and feet, irregular heartbeat, watery and itchy eyes, generalized itching, depression, and more.

Most symptoms are now known to overlap with the world’s fastest spreading infectious disease – Lyme – which can be successfully treated with antibiotics, but MCS cannot.

The inconvenient truth is that MCS is caused by substances upon which industrialized economies depend. This situation began some 200 years ago when coal-fired industries caused asthma, allergies, and cancer cases to appear in unprecedented numbers. Since then, tens of thousands of even more toxic substances have become part of our environment — with a predictable increase in corporate and government attempts to avoid responsibility.

The problem with MCS is that it challenges the way we run our world. It challenges the chemical industry in the same way that cancer research challenged the tobacco industry. Both industries brought their products to market before their safety was established, and both have to face the fact that these products are not, and never will be, safe.

In addition to industrial toxic chemicals and tobacco, the last decade has also shown up the pharmaceutical industry for the toxicity of many of its products.

When a person carries an MCS diagnosis, the competing interests of insurance companies, employers, and governments often erect seemingly insurmountable barriers for the applicant. That’s because treating environmental illness requires sophisticated, expensive, highly individualized detoxification and nutritional support protocols.

Science, Medicine, and Law Acknowledge MCS as Legitimate Diagnosis

In 2004, Ontario’s College of Family Physicians published a masterpiece of a report on the effect of pesticides on children, which led then Premier McGuinty to ban the use of cosmetic pesticides in 2008. Most Canadian provinces have done the same.

In 2011, Women’s College Hospital produced a report that everyone suffering from MCS should read. It is entitled: “Environmental Sensitivities – Multiple Chemical Sensitivities Status Report, Environmental Health Clinic, Women’s College Hospital.”

Also in 2011, the Canadian Environmental Law Association, Ontario College of Family Physicians, and the Environmental Health Institute of Canada published a review on what exposure to hazardous chemicals does to cause chronic disease. It is an excellent tool for people working to clean up toxins in schools.

In 2015, the pesticide Roundup (glyphosate) was declared a carcinogen by the International Agency for Research in Cancer (IARC), and California made labeling that product as such legally mandatory in June 2017.

One of the most significant drivers for change has been consumer demand. When people ask for fragrance-free products, pesticide-free foods, and so on – the industry hops to it. And fast! The power of consumer demand cannot be overstated.

Misleading Quebec Report on MCS Puts Patients at Risk

Now for the bad news. In June of 2021, Quebec’s Institute of Public Health published a massive new report on Multiple Chemical Sensitivity under the direction of its department of environmental toxicology. The report declared that MCS is merely “a belief system” which can be lumped together with what they claim are “similar belief systems such as Post-Traumatic Stress Disorder, compulsive-obsessive disorder, chronic fatigue, electrosensitivity, fibromyalgia, chronic anxiety, depression, somatization disorders and panic disorder.”

The 800-page Quebec report backed up its assertions with over 4,000 mostly irrelevant and outdated citations, apparently chosen to misguide the reader into accepting their conclusions. Wow! What a way to dismiss the many and varied health problems caused by a toxic environment while disregarding mountains of mainstream research that confirms the existence of Multiple Chemical Sensitivity.

Needless to say, the report is without merit due to its lack of up-to-date scientific evidence about Multiple Chemical Sensitivity. It is an embarrassment to science and to Canada within the domain of the world’s medical science. Why should you care? Because it will influence treatment protocols used for MCS patients across the country.

In September when this report was released, a momentous event occurred at the same time. The Nobel committee announced that David Julius of the University of California at Berkeley, and Ardem Patapoutian of the Scripps Research at La Jolla in California, were to receive the 2021 Nobel prize for their discovery of how the experience of the outside world (for example temperature and smell) induces an electrical signal in the nervous system for processing by the brain.

Certain so-called ‘vanilloid receptors (TRPV1)’ that the Nobel prizewinners had discovered were found to be widely distributed in the central and peripheral nervous system and are genetically anchored. TRPV1 and their companions now not only explain the pathophysiology of temperature, smell, and pain, but – guess what! – that system of receptors is “hyper-responsive to environmental toxins observed and reported in MCS”, as Martin Pall had already reported.

This is an exciting discovery because it now provides the scientific explanation for Multiple Chemical Sensitivity phenomena.

So, in light of that breakthrough research, Quebec’s Public Health report on MCS is irresponsible, and a hazard to public health. The significance of that report, which was not published in a peer-reviewed journal but represented as expert opinion to support public health policy, is huge. For example, a $2 million safe housing project previously approved for MCS-diagnosed people in Quebec, was cancelled recently on the strength of the report. So it has become apparent that the political precedent is now set and all current and future discussion about Multiple Chemical Sensitivity will be railroaded away from published peer-reviewed science right across Canada, and towards uninformed opinions by those with a political or economic agenda.

The report’s misrepresentation of scientific literature is demonstrated in two ways: firstly, the authors don’t go beyond 2009 except in a few cases which are not relevant to MCS. Why? Because that’s the year the creation of the Quebec report went into hibernation until arriving in print in 2021 as supposedly ‘new’. Basing new research reports on publications more than 10 years old would never pass peer review! This report was therefore dead on arrival. (Current literature would bring the Quebec authors face to face with the TRPV1 vanilloid receptors and that would render their findings as completely invalid.)

Secondly, the misrepresentation of scientific literature becomes evident when we see who is being cited (accidentally maybe?) to support their conclusions, such as the MCS-literate researchers who in the referenced articles say exactly the opposite of what the Quebec authors assert. For example, Dr. Kathleen Kerr and Dr. Lynn Marshall of Toronto’s Environmental Health Clinic in Women’s College Hospital do not correlate MCS with phobias, as claimed (without evidence cited) in the Quebec report.

And the worst part of this report is that the authors made their pronouncements without consulting any with clinicians who are currently treating MCS patients. How dare they present themselves as experts on MCS?

Ironically, the Quebec report does admit that many countries recognize the MCS diagnosis, provide treatment for it, and compensate debilitated victims. However, Quebec Public Health opines that while those so-called MCS patients have a hard time, they need to be helped out of their debilitating “belief system”. Strangely, no mention is made of the environmental health clinics already operating in various parts of Canada and the world (such as Germany, Japan, many EU countries, the USA, etc.).

These Quebec authors even go so far as to state: “At low concentrations, like those found in the usual environment [what exactly is this usual environment and where do we find these low concentrations?] these chemicals [even toxic ones] do not reach the brain.”

The authors seem to have forgotten that our man-made chemicals can be lethal and cause chronic illness even with minute exposures. For example, DDT is not good for you as those 1950’s advertisements claimed because a little supposedly just kills mosquitoes but not humans. And bovine growth hormone is carcinogenic when consumed in minute amounts in contaminated milk or meat. As well, mercury amalgam when swallowed does not create a problem, but its methylated gas outgassing from dental composites into the brain can wreck the central nervous system.

Here are some key points to take away:
1. Quebec’s MCS patient group has announced that an action against the unconscionable report of the INSPQ (National Institute of Public Health, Québec) on Multiple Chemical Sensitivity (MCS) has been launched. Please go to to learn more and join this effort.

2. According to the Canadian Community Health Survey (CCHS) of Statistics Canada, over one million Canadians have a formal medical diagnosis of MCS with 72% of that population identifying as women and nearly 50% seniors (CCHS, 2020). MCS is a disability protected under the Canadian Human Rights Act (2007).

3. The same chemicals that are implicated in global warming, are also the key actors in MCS. Climate change is visible also in MCS; the prevalence of diagnosed cases of MCS is rising (CCHS, 2015-2016, CCHS, 2020).

4. MCS is situated at the intersection of gender equality, sustainability and accessibility. It is critical that governments take action to remove barriers to care and accommodation for the MCS disabled.

Take Action Now!

For more information visit:


• The Quebec report: Watch for the chapter headings which fool you into believing these areas were actually studied. The most relevant is totally avoided.
• Read the excellent response by Dr. John Molot written October 15, 2021 on the website of Environmental Health Association of Quebec
• The 2021 Nobel Prize for medicine:
• Molot, J, Sears, M., Marshall, L. & Bray, R. Neurological susceptibility to environmental exposures: pathophysiological mechanisms in neurodegeneration and multiple chemical sensitivity. Reviews in Environmental Health, Sept. 2021
• Martin Pall et al. The vanilloid receptor as a putative target of diverse chemicals in multiple chemical sensitivity. Archives of Environmental Health 59 (2) 2004
• Ashford, N. & Miller, C. Chemical Exposures – Low Levels and High Stakes, 1998

Sources and Resources:
• American Academy of Enviro Med:
• Environmental Health Clinic, Women’s College Hospital, 76 Grenville Street, Toronto

Helke Ferrie is a medical science writer with a master's degree in physical anthropology. Her specialty lies in investigative research into ethical issues in medicine and the politics of health. She started her investigative journalism career in the mid-1990s, looking at issues of medicine and environment. She has been a regular contributor to Vitality Magazine ever since. Helke has also authored books on various subjects including: "Ending Denial: The Lyme Disease Epidemic", "What Part of No! Don't They Understand: Rescuing Food and Medicine from Government Abuse", and "The Earth's Gift to Medicine".


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  1. 5 letter words
    July 14, 00:32 5 letter words

    Thanks for the sharing

    Reply this comment
  2. J
    October 24, 14:36 Josie

    Thank you Helke. You have been a Godsend to those of us with MCS.

    Reply this comment
  3. l
    June 04, 17:32 louisee

    I am in the process of finding accommodation in a bldg that is not a multi-unit one, because I get seriously ill from odours and vapors from people smoking pot for medical purposes or recreation. Things were fine in present location until someone moved in in close proximity to my unit, the odours, vapours, etc. go through the boiler system type heating system and from the time the heat is turned on in Oct to the spring, I suffer from asthmatic like attacks, complete exhaustion, headaches, loss of appetite and low sodium, cancer, etc. It is unbearable and hard to prove. It is hard to find people that actually believe the torment and horrible results, depression, etc. from this (just as if someone would ever make up such stuff). Landlords don’t care if the tenant moves out, they just charge much higher rent to new tenant. I am 89 yrs of age, had to relocate 2 yr. 3 mo. ago for the same reason at great expense and stress to me, going to an apt where I was paying $869. incl per mo and now $1425. incl per mo. (same landlord, different city). There was no way he would transfer me at same rate of rent, or help pay for the move! I call it senior abuse and a human rights issue. I have never gone to an allergist but know that I am highly sensitive to certain chemicals,. In a case such as this, it is impossible to get the smells out of the apt. as the bldgs are old and there is not a proper ventilation system, Smoke Free Ontario details this in their brochures that were given to me when I was in hospital, I have been hospitalized various times because of this with everything from fluid on the lung, , heart failure, low sodium, cancer, etc. Previous to the episode in London, my health was amazing for my age, but this has weakened my system greatly, and I still have to hire someone to pack my stuff, hire a mover, and pay more rent, if I can find a place in a duplex, triplex or fourplex so I, hopefully, wont encounter the same situation at the new place. All this is too much and sometimes I feel its not worth the effort to try and get away from it. Thank you for your informative articles in Vitality Magazine, I read it cover to cover, and now on-line! They are real eye-openers!! PS i go on monday for ultrasound of abdomen, and tuesday for bone density test, wednesday for two blood tests for two different doctors, all because of things I have been suffering from as a result of the above.

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