The Wildly Unreasonable Toxicity of Plug-in Air Fresheners

By Rick Rydell

Originally published by A Voice For Choice Advocacy on January 11, 2024.

“Loads of chemicals and hazardous wastes have been introduced into the atmosphere that didn't even exist in 1948. The environmental condition of the planet is far worse than it was 42 years ago.”

~Gaylord Nelson (1916–2005), American politician, environmentalist, and creator of Earth Day

Whether you’ve got stinky teenage boys, dirty diapers in the trash can, an old gym bag that makes your eyes water, or a dog with a distinctive post-meal odor, the home scent industry has an easy solution for you: plug-in air fresheners. 

No longer content to just be room perfume, plug-in air fresheners (sometimes called diffusers) are often advertised with a host of claims. Take one Walmart ad: 

“Plug-in diffusers…enhance your living space with a long-lasting scent and help to relieve stress. Air fresheners designed with mood lights also bring a serene feeling to your home. Plug-in air fresheners…give your bathroom an inviting, spa-like ambience. They also function as mini humidifiers, helping to hydrate dry skin. If you have pets or lingering odors, look for plug-in air fresheners that not only produce a refreshing scent but also help to cleanse the air.”

To recap: According to Walmart, plug-in air fresheners not only make a space smell better, but relieve stress, bring serenity, provide ambience, moisturize skin, and clean the surrounding air. 

Remarkable—quite the marketing stretch-of-imagination.

Perhaps that’s why the worldwide air freshener market (which includes not only plug-ins, but other products such as sprays, candles and the like) was worth $12.2 billion in 2021 and is projected to reach $27.7 billion by 2030.

How air fresheners work: Explained by Porex Filtration Group:

 “There is a porous rod that wicks the fragrance from the bottle or container to the top, where it’s then diffused into the room in a controlled manner. This wick is what allows you to smell all that delightful fragrance!”

Venom in the Sockets

Before plug-in air fresheners arrived on the scent scene, aerosol cans were the norm. The sprays eventually fell out of fashion, however, thanks to their tendency to deplete the ozone layer. That’s when plug-ins came to the rescue in the 1990s. Their appeal was obvious: Plug-ins were inexpensive, pleasant to smell (yet off-putting to those who lean toward “natural living”), easy to use, and came in a huge variety of scents, colors and styles.

The last few years of scientific research may put a damper on consumers’ enthusiasm, though. Studies have begun piling up showing that plug-in air fresheners are quite toxic to both human and animal health. Despite Walmart’s air-cleansing claims, plug-ins apparently dirty whatever room they are supposed to be cleaning.

The main culprit? Phthalates. Pronounced “thal-ates,” these little chemicals are well-known to cause hormonal abnormalities, birth defects, and reproductive problems, and plug-in air fresheners rely heavily on them. One study, “Clearing the Air: Hidden Hazards of Air Fresheners,” found phthalates in 86 percent of air fresheners, including the plug-in variety, even those branded “all natural” or “unscented.” 

Furthermore, according to the Natural Resources Defense Council:

“There are no labeling requirements and even ‘natural’ products can contain toxic chemicals,” meaning “it is virtually impossible for the average consumer to know which products may pose a risk.” 

Another study, from Environmental Health Perspectives, found that phthalates may be compromising the integrity of human sperm. It's not phthalates alone inside that pretty little plug-in. Other chemicals in common in-wall air fresheners include volatile organic compounds (VOCs)—naphthalene, benzene, formaldehyde, toluene, acetaldehyde, and pentachlorophenol.  

The state of California has labeled these as toxic via Proposition 65, warning consumers to stay clear as much as possible. If you don’t, California says, you run the risk of brushing up against developmental issues, cancer, reproductive harm, and more.

Simple common sense dictates that no smell can truly scrub away something bad in the air, only cover it up with a new scent. However, strong, heavy chemicals may neutralize the odor. So how do companies get away with such obvious—and hidden—chemical wrongdoing? The answer is a subtle mixture of handy “we just don’t know” denials, and protective industry regulations.

From the get-go, companies do not have to disclose what makes their fresheners smell like a bed of roses, or to some … a perfume factory spill. Fragrances, in fact, are considered “trade secrets,'' and therefore do not need to be listed with the other ingredients. 

Even the explicitly listed ingredients in air fresheners get a “free pass.” Take Glade’s “Lasting Impressions” plug-in in Hawaiian Breeze® and Vanilla Passion Fruit. In its eight-page product information insert (yes, those exist), Glade lists the following:

• “Chronic effects

• Carcinogenicity: no data available

• Mutagenicity: no data available

• Reproductive effects: no data available

• Teratogenicity: no data available

• Sensitisation: not known to be a sensitizer”

What they really mean is that no data has been done on that specific plug-in with that specific flavor. It’s as if they’re saying … Sorry, consumers, we simply don’t know if this stuff we’re selling you to blast through your home 24/7 is dangerous or not; that’s up to someone else to determine. 

Plug-in air freshener companies have, in fact, been put on warning notice by Californian government for their Proposition 65 violations in the past. Other scientists have called for further study into the real-world effects of these penetrating devices, noting: 

“[The ingredients] raise concern about possible contribution to acute airway effects, in particular…because it is generally used as a constant source.”

Nearly everyone can relate to those “acute airway effects” the scientists mentioned. After all, most have had the experience of instant headaches, watery eyes, scratchy throat, or even trouble breathing when around someone with strong perfume, or in a small room with a domineering air freshener.

More than two million Americans with fragrance allergies will attest to the misery that chemical scents can bring on. A doctor from the American College of Allergy, Asthma and Immunology estimated that one-fifth of the population has suffered health problems from air fresheners. “This [air freshener] is a much bigger problem than people realize,” said Dr. Stanley Fineman.

Kids and Kitties

Plug-ins can damage even allergy-free bodies far more seriously and quickly than a simple half-hour headache or late-to-arrive cancer diagnosis. Take the British toddler who was left in a coma after drinking the liquid from a plug-in air freshener. Or the two Walmart shoppers who died after purchasing and using air fresheners containing deadly bacteria.

Even if you don’t die or end up in a coma, plug-ins can cause those other aforementioned issues, including migraine headaches, asthma attacks, breathing difficulties, respiratory difficulties, mucosal symptoms, dermatitis, infant diarrhea and earache, neurological problems, and ventricular fibrillation.

These problems apply not only to adults, but to much-smaller children and pets. Internet chat rooms and blogs abound with personal anecdotes about babies, cats, dogs, and other animals suffering after getting into plug-in air fresheners. 

It makes sense when you consider where these room fresheners are typically located—colorfully displayed in tantalizingly forbidden wall sockets, often within reach of short and curious creatures with propensities to explore the world orally.

Research at Northern Arizona University shows that some VOCs (a common ingredient in plug-in air fresheners) can cause cancer in animals—and that’s without direct ingestion. Even a small amount near humans and animals can lead to reduced lung function, found by a study from the National Institute of Environmental Health Sciences (NIEHS). And a type of benzene has been linked to pet bird deaths when cages were left near plug-ins.

Not only that, but if a scent is strong to humans, how much more torturous must it be to a super-sniffer like a canine? One headline summarized it simply: “No, plug-in air fresheners are not safe for pets.”

“Consumers should be aware that the pretty label and sweet scent may mask something much less pleasant,” said Gina Solomon, a senior scientist at the Natural Resources Defense Council (NRDC). 

Her fellow scientists went even further in the same report: 

“The difficulty of avoiding general exposure is all the more reason to eliminate further exposure in an environment over which you have much more control—your home.”

Indeed, between its toxicity, nasty side effects on all sorts of creatures, unregulated industrial nature, and unknown scent makeup, plug-in air fresheners have left a putrid path behind.

In addition to plug-in air “fresheners,” be aware of harmful toxins in aerosol sprays, battery-operated tabletop scent releasers, reed diffusers (those nasty sticks festering in liquid; no matter how pretty they may look), and automobile “odor-fighting” car fresheners. If a product says “natural,” don’t let it fool you.

Natural Nontoxic Air Freshening Ideas for Your Consideration

Is the only logical response to this knowledge about plug-in air fresheners to throw away the products you enjoy, while resigning yourself to perpetual putrescence? Not at all. 

In fact, a house smelling like a house might be just alright; it doesn’t need to smell like a dewy honeymoon sunset from a Fiji beach. If everyone in your house is bathing, and “normal” cleaning happens regularly (no moldy food, pet messes or dirty laundry left out for weeks on end), your home will smell like it’s supposed to.

When you do notice an indoor odor, go old-fashioned! Open windows. Simmer a pan of water with cinnamon sticks and citrus rinds on the stove. Bake fresh bread. Toss together a blend of dried herbal potpourri: 

“Creating an aromatic potpourri with a combination of dried flowers, fragrant herbs, and essential oils is a great way to scent any room. The dried flowers can include roses, marigolds, lavender or daisies for stunning color and texture.

Aromatic herbs such as rosemary, thyme, oregano or sage bring a wonderful fragrance to the mixture. Lastly, adding essential oils like lemon verbena, jasmine or sandalwood can enhance the aroma of the potpourri.

Consider blending different oils or adding petals from natural flowers like chamomile or hibiscus for extra scent. To create an even more unique potpourri blend you could add pieces of cinnamon sticks, dried orange peel or star anise for a truly delightful smell!”

Splash organic essential oils on fabric or in a bowl of warm water. Bring in a bouquet of roses or hydrangeas. Open a box of baking soda. Take to heart: No artificial olfactory high is worth the cost of your and your family’s health.

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