Multiple Chemical Sensitivity

What is it?

"Multiple chemical sensitivity" (MCS), or "environmental illness" or "sick building syndrome" are all terms to describe the problems of exposures to chemicals that adversely affect our health. It is also now known as idiopathic environmental intolerances (IEI).

Once workers have been sensitized to chemicals at work, their sensitivities often broaden to a wide variety of chemicals that in the past did not affect them. These can range from perfumes to paints, from carpets to fuels.

If worker have the following sorts of symptoms that get better after they go home or on the weekend, they may be experiencing the early signs of multiple chemical sensitivity:

 Burning eyes, nose
 Cough, sore throat
 Difficulty breathing
 Sinus pain
 Difficulty concentrating
 Difficulty sleeping
 Memory loss
 Abdominal pain
 Aching muscles or joints
 Skin disorders

Unlike a cold or the flu, symptoms do not clear up within days. After weeks or months of exposure, symptoms may become chronic and only get better after a very long time away from the building.

So, multiple chemical sensitivity is a chronic condition characterized by:

    • multiple symptoms (many and variable)
    • in multiple organs (minimum 2, usually 4+)
    • affecting multiple senses (usually 2 to 4)
    • triggered by multiple chemicals (and often also by other stressors and stimuli)
    • waxing and waning with exposures at or below levels previously tolerated

The abstract of a recent report by the Danish Environmental Protection Agency, based on a study of the scientific literature on MCS (which in Denmark is called odour and chemical hypersensitivity) states:

'It is concluded that MCS - a new health disorder which has been described during the last 20 years - is a real condition. MCS differs from the common scientific understanding of illness because the condition is always manifested by multiple non-specific symptoms from different organs at the same time and because these symptoms may occur after exposure to chemicals at very low concentrations.'

Persons with multiple chemical sensitivity may become sensitized to these chemicals:

 Aerosol air freshener 
 Aerosol deodorant
 After-shave lotion
 Asphalt pavement
 Carpet/carpet glues
 Carpet cleaning products 
 Cleaning products
 Cigar smoke
 Cigarette Smoke
 Colognes, perfumes
 Deodorant and anti-perspirant that are perfumed
 Diesel exhaust
 Diesel fuel
 Dry-cleaning fluid
 Floor cleaner Varnish, shellac, lacquer
 Furniture polish
 Garage fumes
 Gasoline exhaust
 Hair spray
 Nail polish and Nail polish remover
 Oil-based paint
 Paint thinner
 Perfumes and body sprays
 Perfumed shampoo and other hair products
 Pesticides and herbicides
 Public restroom deodorizers
 Tar fumes from roof or road
 Tile cleaners
 Wood smoke

and any other chemicals that may be used or produced in the workplace.

Which workers are affected?

Workers in a wide variety of workplaces - from retail to office, from universities to hospitals, from factories to construction - can develop multiple chemical sensitivity. Low level exposure of chemicals given off by a wide variety of sources including solvents, paints, cleaning products, carpets, wall coverings, photocopiers, new clothing, and medicines can result in sensitivity developing among some people. These exposures are usually far below the maximum allowed under health and safety regulations but, since they occur over time, the sensitivity builds up in the exposed person. Exposure standards are set for each individual chemical, but workers are often exposed to a "chemical soup" in workplaces. Sometimes one big exposure to a chemical can start the syndrome.

How does multiple chemical sensitivity affect the body?

 We breathe in many substances, we eat food with chemical additives and many sensitizers get into our bodies through our skin both unintentionally and intentionally. Perfumes, soaps, shampoos, deodorants and hair sprays, for example, are designed to be worn and used or absorbed onto and into our skin.

Our bodies evolved in a chemical-free world. Over the past few hundred years, however, we have invented new chemicals that we are biologically not equipped to handle. The chemical industry keeps inventing new products and is not keen to acknowledge that their profitable products may be causing us substantial harm.

How can co-workers help?

It is very important that individuals who do contract multiple chemical sensitivity syndrome are believed, even though we may not know the precise chemical cause of the problem. Multiple chemical sensitivity does exist.

How is it treated?

There is no real treatment for the syndrome other than removing the person from exposure to harmful chemicals. Their bodies will usually heal themselves over time with rest, good nutrition, exercise when ready to rebuild unused muscles, and social support. People may have become sick over a period of months or years and so they will not get well overnight. Small amounts of chemicals that never bothered them before may now cause problems at minute amounts. This sensitisation may last many years.

What are the measures to prevent MCS?

Measures to prevent, or minimise, the problems of multiple chemical sensitivity include:

    • Better general ventilation. Workers need fresh air
    • Local exhaust ventilation for sources of contaminants such as photocopiers
    • Natural fibres for floor coverings and furniture
    • Natural wall coverings rather than those that contain formaldehyde 
    • Environmentally friendly cleaning products 
    • Indoor plants to help clean the air 
    • Banning pesticides, especially indoors, or at least severely restricting their use and using organic pest control wherever possible
    • If workers do contract multiple chemical sensitivity, they need:
      • The right to timely investigation of health complaints and resolution of workers' compensation claims
      • The right to be believed even though the precise original cause of the syndrome may never be determined
      • The right to participate in support groups with fellow sufferers
      • The right not be harassed or discriminated against in job assignments and promotions
      • The right to job security, integrity and reasonable accommodation
      • The right not to be exposed to sensitizers such as cigarette smoke and perfumes

Once people have become sensitised through this workplace exposure, they can develop sensitivities to a wide variety of workplace and non-workplace chemicals from food additives to vehicle exhaust, from carpets to caffeine, at levels so low that other people can barely detect them. We must ensure that these sensitised individuals are protected to the greatest extent possible.

Australian research (March 2018)

Multiple chemical sensitivity rates triple in 10 years
The number of people diagnosed with potentially disabling multiple chemical sensitivity (MCS) has grown by 300 per cent in a decade, with three in five sufferers taking sick leave or leaving a job due to fragranced products in the workplace, an Australian expert has found.

From a cross-sectional survey of 1,137 adults in the US, University of Melbourne Professor of civil engineering Dr Anne Steinemann found 12.8 per cent had been medically diagnosed with MCS and 25.9 per cent reported experiencing chemical sensitivity. She also found that 70.3 per cent of people with diagnosed MCS are not able to access places that use fragranced products such as air fresheners because of the severity of their symptoms, and 60.7 per cent lost work days or a job in the year leading up to the survey due to illness from workplace fragranced products.

According to the study, products or circumstances that trigger reactions in people with diagnosed MCS include: air fresheners and deodorisers (67.6 per cent of sufferers); scented laundry products coming from dryer vents (57.9 per cent); being in a room recently cleaned with scented products (67.6 per cent); being near someone wearing a fragranced product (65.5 per cent); and general fragranced consumer products (73.1 per cent).

Over 70 per cent of MCS sufferers favour fragrance-free workplace policies - and given the increasing prevalence, this is something employer should be considering.
Read more: Steinemann, A. National Prevalence and Effects of Multiple Chemical Sensitivities. Journal of Occupational and Environmental Medicine, [Open access] Volume 60, Issue 3, March 2018.  More on Perfumes in the workplace Source:OHSAlert 

Recent research:

A 2017 scientific review described MCS as "a complex syndrome that manifests as a result of exposure to a low level of various common contaminants."[1] A 2019 review described the condition as an "acquired disorder characterized by recurrent symptoms, affecting multiple organs and systems, which arise in response to a demonstrable exposure to chemicals, even at low doses, much lower than those that would cause a reaction in the general population."[2]

Chemicals that are common triggers for MCS symptoms include pesticides, petrochemicals, formaldehyde and fragranced products.[3] Natural irritants like mold and wood-fire smoke are also often triggers.[4]

More information

  • Health and Safety Information Topic Multiple Chemical Sensitivity from the US Department of Labor
  • A scientific review undertaken by NICNAS, the Australian regulator for industrial chemicals and the Officer of Chemical Safety: Multiple Chemical Sensitivity: identifying key research needs [pdf]. Note: this is a copy of the Draft report. Also: Multiple Chemical Sensitivity Review Fact sheet (currently unavailable)
  • A US website with resources and referrals for MCS
  • an exposure log which is part of UNIFOR's Prevent Cancer Campaign (UNIFOR is a Canadian manufacturing union group which the Canadian Autoworkers now form part of)
  • Multiple chemical sensitivity, #MEAction Encyclopedia

This material is based on Multiple Chemical Sensitivity - A Guide for Workers from the Canadian Autoworkers Union (with many thanks!) Their material was adapted from Lax MB, Henneberger PK. Patients with multiple chemical sensitivities in an occupational health clinic: presentation and follow-up. Arch Environ Health 1995; 50:425-31.

Last amended February 2020