Scent evokes strong associations

Our sense of smell is linked in our brain to perceptions that feel personal. For example, our self-image and feelings of self-worth are often linked to smelling a certain way. In addition, memories are more easily evoked by smells than by any other sense. We have strong emotional reactions to certain kinds of smell, and tend to think of the reaction as an intrinsically real characteristic of the thing that smells. But we know that some of these reactions have been trained into us. For example, D. Michael Stoddart observes, in his book The Scented Ape:

"It is interesting to recall that in the twentieth-century world clothes-washing powders and fabric conditioners are sold much more on their ability to leave laundry perfumed than to leave it clean—though the odours are said to be of freshness. Cleanliness equates with fragrance and to godliness; it is only comparatively recently that surgeons have been persuaded that disinfectants do not need to have strong smells to be effective....”

History Does Not Equal Safety

In addition, we know that just because a product has long been used, doesn’t mean it’s harmless: witness the poisoning of hatmakers by mercury, or of anyone who wore face powder, for hundreds of years, because the lead in it was necessary to give the skin that elegant “porcelain” color.

Now we also are beginning to see that many of the ingredients of fragrances — some used for a long time — show serious toxicity in laboratory testing. For example phenyl propyl alcohol, which is used in fancy bouquet scents, is rated with a moderate toxicity, appears on the EPA’s chemical inventory under the Toxic Substance Control Act, and is a recognized skin irritant. Coumarin, widely used in heavy floral or leather scents, is rated “severe animal toxicity, or material is explosive, highly flammable, or highly reactive -- and is a recognized irritant of the eye and respiratory tract.” (See reference 1, below.)

For more on fragrance toxicity, see The Health Risks of Twenty Most Common Chemicals Found in Thirty-One Fragrance Products By a 1991 EPA Study .)

Low-dose toxicity

Some argue that the amount you get exposed to in real life is such a minute fraction of the doses used in lab testing, that they aren’t really toxic in normal usage. There are three problems with this way of thinking:

First of all, some substances have strong effects at minute doses; we see this in certain vitamins and drugs — and some would argue, in homeopathy. The issue is not really dosage but bioactivity at various doses.

Secondly, low doses can accumulate. We all know people who develop unexpected allergies as adults, having been exposed to the allergen many times before the body finally had too much. In addition the limbic brain can be permanently altered by a process known as kindling, which results from repetitive irritation at a level which would not by itself be dangerous. (More on this later)

Finally, the neurons of the sense of smell, unlike those of any other sense, import into the brain actual molecules of what is smelled. Thus brain cells are subjected directly to scent toxins — unlike other poisons, which have to pass the blood/brain barrier. Minute amounts are highly effective when they reach a susceptible target with perfect aim.(See References 2 and 3, below)

So fragrance neurotoxins are hazardous, even in the small amounts of normal exposures.

Increasing exposure

Moreover everyone receives multiple exposures, from the wide variety of products that are scented — from ads in magazines and air in stores to all kinds of cleaning products, "air fresheners," cosmetics, dishwashing sponges, plastic toys, plastic clothes hangers.... The effect is cumulative.

Fragrances have mainly been added to household products since World War II, due to the rise of inexpensive, commercial synthetic fragrances. Before that, natural fragrances, which were always rather difficult to obtain and expensive to extract, were rare and expensive, with the result that fewer people were exposed to them.

In 1990, an independent researcher who contacted the FDA privately reported:

The FDA acknowledges that the incidende of adverse reactions to perfume products appears to be increasing and that these reactions may involve the immune system and may also be neruotoxic reactions. (see Reference 4, below.)

Fragrance is also problematic for people besides the victims of EI/MCS: people who suffer from headache, allergy and asthma from other causes. (See Reference 5, below.)

"Fragrance -free" is not

Some manufacturers are sensitive to the increasing load of scent on our air, and offer unscented products. However:

..."fragrance-free" on the label does not mean that a product has no added fragrance. Masking fragrance can be added "to mask the fatty odor of soap or other unpleasant odors." "Fragrance-free" is a term, like "hypoallergenic," that has no government definition. In fact "[h]ypoallergenic can mean almost anything to anybody," according to the director of FDA’s division of colors and cosmetics. Likewise, "dermatologist tested," "allergy tested," "sensitivity tested," and "nonirritating" on the label carry no guarantee that [the product so labeled] won't cause reactions.

(See Reference 6, below.) 

For recommendations for the least fragrant substances I've found, see Products for the EI Household.

References

1. “Perfume: The Romance... and the Reality” by Louise Kosta, The Human Ecologist, issue no. 67 (Fall 1995), p. 13.
2. “Kindling, TDS and Focal Brain Injury in Chemical and Electrical Sensitivity” by Jay W. Seastrunk II, MD., Our Toxic Times vol. 8, no. 3 (March 1997) pp. 20-23.
3. “Olfactory Primary Neurons as a Route of Entry for Toxic Agents into the CNS,” by Lloyd Hastings and James Evans, which you can order from the Chemical Injury Information Network; see the library on their website.
4. The Human Ecologist, issue no. 47 (Fall 1990), p. 17.
5. “The Numbers Game” The Human Ecologist, issue no. 55 (Fall 1992), p. 6.
6. “Focus on Fragrance and Health,” by Louise Kosta, in The Human Ecologist, issue no.55 (Fall 1992), p. 5