One of my neighbors raised the topic of toxins in the dryer effluence from our buildings' laundry rooms. That's not particularly surprising, but she claimed there was evidence that the trace toxins in the air are dangerous. It sounded just plausible enough to to possible, especially given the volume of laundry done, but, given the source, I decided to check into it before I worried.

Turns out there are plenty of examples of people claiming this is a serious health hazard:

  1. Holistic Help: Chemicals Found in Dryer Exhaust and There (sic) Toxicology
  2. Mercola: The Household Appliance that Releases 600 Potentially Dangerous Chemicals into the Air
  3. Natural Life Magazine: Are Soft Clothes Really Worth It?
  4. One Christian Ministry: Clothes Dryer Vent Exhaust Poisoning USA Neighborhoods, Families, Children
  5. Invisible Disabilities: Why Fragrance Free?

The only basis for most of which seems to be, when they bother to cite a source, this 2011 study, Chemical emissions from residential dryer vents during use of fragranced laundry products which did find toxins (again, not surprising). According to the press release, they went so far as to call dryer effluence a pollutant. There's also this older EPA study cited by the Invisible Disabilities article.

What I haven't seen is anything which says these emissions are actually dangerous to people in the concentrations that are actually present. Most of this seems like a lot of overreaching and overreacting, but I'd like to know more if there is more to know.


2 Answers 2


Not even close to dangerous enough to worry about

I looked up the Material Safety data Sheet (MSDS) for the OSHA (United States) for a generic fabric softener. The following table is the LD50 (lethal does concentration for 50% lethality in a typical human) for each ingredient.

MSDS LD50 Table for Fabric Softener

As noted in the table, the LD50 for the fragrance is typically greater than 5 grams per kilo of human. While not considered harmless, you would need to inhale a ridiculous amount of dryer exhaust to even notice health effects.

At <1% (I used 1% for calculations), a 32oz (~1L) bottle (net weight 2.64lbs or 1.2Kg) would contain less than 12mg of fragrance per bottle. You would need over 833 bottles worth per kilo of bodyweight to inhale the LD50 lower limit, and that's only if every bit of it was inhaled.

Typically the MSDS becomes relevant for the workers producing the product, as the ingredients are at MUCH higher concentrations where its made.

  • 2
    Your screenshot of the PDF cuts off the critical bit: the LD50 is oral toxicity: that is, exposure by ingestion. It says absolutely nothing about the LD50 for exposure by inhalation (which is generally much lower). As an example of the difference, the rat inhalation LD50 for sodium carbonate is 2300mg/m^3/2H.
    – Mark
    Commented Apr 19, 2022 at 2:33
  • This link describes 2300mg/m^3 as being slightly toxic via inhalation, with a proposed lethal human dose as 600ml, which would take a vast volume of detergent to achieve, let alone inhale. Using the same 1% roundup as above, it would take 60 bottles of 100% inhalation to produce that lethal dose. Even being an order of magnitude less substance needed to kill leaves a ridiculous amount.
    – GOATNine
    Commented Apr 19, 2022 at 3:31
  • 1
    I picked the sodium carbonate as an example because it's the one where I could find inhalation toxicity. Other ingredients (such as the "essential oils and botanical extracts") are likely to be considerably more toxic.
    – Mark
    Commented Apr 19, 2022 at 3:37
  • @Mark I suggest you research and post an answer then. I would genuinely like to know the toxicity of each of those ingredients and would be happy to be proven wrong.
    – GOATNine
    Commented Apr 19, 2022 at 3:44
  • My research is coming up with a strong case of "we don't know", although airborne vanillin appears to be at least a hundred times more toxic than ingested vanillin.
    – Mark
    Commented Apr 19, 2022 at 21:59

We don't know.

When deciding if fumes are dangerous, the relevant measure is the "LC-50", the airborne concentration that is lethal to 50% of test subjects. Ingestion LD-50s are of limited value here, since the lungs provide far more direct access to the bloodstream than the digestive tract does. In the absence of explicit toxicology information, occupational exposure limits are an indication of hazard levels.

I searched for safety data sheets for the ingredients in the fabric softener listed in the other answer, and checked at least three for each. I was able to find inhalation LC-50s for sodium carbonate (2300 mg/m^3/2H), vanillin (57 mg/L/96H), and raspberry ketone (non-toxic per EC 1272/2008). I also found exposure limits for d-limonene (20 ppm per ACGIH), calcium chloride (no limit per OSHA, NIOSH, or ACGIH), and propylene glycol (10 mg/m^3 per US WEEL).

For everything else (water*, dihydrogenated palmoylethyl hydroxyethylmonium methosulfate, benzisothiazolinone, bitter orange extract, orange peel oil, eucalyptus globulus leaf oil, hexyl acetate, juniperus mexicana oil, lavandula hybrida oil, pogostemon cablin oil, and linalool), the inhalation toxicity hazard was either "no information available" or simply not included. For many of the oils, the entire toxicity section is "no information available".

*Yes, there are serious safety data sheets for water.

  • How very stupid to impregnate laundry with so much perfume & stuff, just to evaporate off a lot of it in the dryer. But the issue here is also on skin contact for the rest when worn (imo, + you smell it, it still evaporates further…). Direct 'toxicity' measured in LD50 is also a herring of colour. Some essential oils may promote seizures, hormonal disruption, can be allergy or photo-sensitizers etc. As long as lists of ingredients remain nondescript ("perfume", "oils") this broadness cannot be answered with too much certainty, & surely not without detailed chemical analysis to begin with. Commented Apr 20, 2022 at 11:04

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