Don’t take our word for it. Here’s every fact on this site, with its evidence grade, its caveats, and a link to the source, so you can check us.
We start you on the strong ones: findings that have been replicated or come from one large, well-controlled study. Moderate and weak facts are here too, labeled for what they are. Use “Link to this fact” to share a single card.
Hidden ingredients / Other evidence
EWG says a cleaning product's A-F grade is not an average of its ingredients' grades: it also counts how fully the maker discloses ingredients, any EWG-approved green certification, and the hazards of the formulation as a whole.
Moderate evidence: This is EWG describing its own method; the formula and weights are not given, and the 2012 method may have changed.
Source: Andrews, EWG, 2012 (web page) Link to this fact
Hidden ingredients / Other evidence
In EWG's cleaning-product grading, an ingredient with little or no public hazard information gets a C, and EWG says lack of safety data is the most common reason an ingredient gets a C.
Moderate evidence: A C therefore often means 'no public data', not 'found hazardous'. Self-described method; no ingredient counts given.
Source: Andrews, EWG, 2012 (web page) Link to this fact
Hidden ingredients / Other evidence
When only a chemical class (not the specific chemical) is known, EWG's cleaning-product method scores the ingredient as the most hazardous chemical in that class.
Moderate evidence: Self-reported rule; the article does not say how often it is applied.
Source: Andrews, EWG, 2012 (web page) Link to this fact
Hidden ingredients / Other evidence
Wet cleaning rests on water, but the detergents and spotting agents hold alcohol ethoxylates, glycol ethers, D-limonene, monoethanolamine, quaternary ammonia and trade secrets; many safety data sheets lacked ingredient data, some noted skin and eye irritation, and ethoxylated alcohols can carry 1,4-dioxane (county study pending).
Moderate evidence: From the county's review of a sample of safety data sheets, not testing of products or garments; the report still rated wet cleaning health-green.
Source: SCDHS 2018 Link to this fact
Hidden ingredients / Review of other studies
Galaxolide and Tonalide are used in perfumes, cleaning products, detergents and cosmetics, so they are typically covered by the single word 'fragrance' on a label.
Moderate evidence: Statement is in the paper's introduction and describes use, not what any given label discloses; this study measures no exposure.
Source: Schreurs 2005, Toxicological Sciences Link to this fact
Hidden ingredients / Other evidence
Limonene and beta-pinene scent terpenes were measurable in every perfume, deodorant and cleaning liquid tested (about 0.1-0.3% and 0.04-0.65% of product weight), even though labels only say 'fragrance' or, for the cleaners, name limonene.
Moderate evidence.
Caveats
Six products; GC-MS of three terpenes only, so other scent chemicals are unmeasured; alpha-pinene was below the detection range. The abstract's beta-pinene range (0.4-0.7%) differs from Table 1 (0.04-0.65%).
Indoor air / Measured in people or real products
Scent chemicals in cleaners and air fresheners react with ozone that drifts in from outdoors to make formaldehyde: cleaning raised formaldehyde by 9-16 ppb for 4 hours, and a plug-in air freshener raised it by about 6 ppb for as long as it ran.
Moderate evidence.
Caveats
Secondary formation only, depends on indoor ozone. The underlying mechanism is now directly quantified at bench scale (Destaillats 2006: formaldehyde 16-38% per ozone consumed for the same three products), but that bench study is the same research group/products/contract as this one, not an independent replication, so the grade is not raised on that basis alone.
Source: Singer 2006, Atmospheric Environment Link to this fact
Indoor air / Measured in people or real products
After 2-7 minutes of cleaning with a terpene cleaner, indoor air chemistry stayed altered for 10-12 hours because the scent chemicals soaked into walls and floors and came back out.
Moderate evidence.
Caveats
Empty chamber; furnished rooms may differ. Singer 2006 (Indoor Air primary-emissions companion, same 50 m3 room without ozone) corroborates the sorption/desorption mechanism directly: alpha-terpineol stays at 260-700 ug/m3 for hours and ~90 ug/m3 at 4-24 h via surface water films and wallboard sorption, and towels left in the room raise 24-h emissions 35-100%. Not independent (same lab/room/products as the ozone paper).
Source: Singer 2006, Atmospheric Environment Link to this fact
Indoor air / Measured in people or real products
In a European study that measured the air 182 adults actually breathed over 48 hours, exposure to pine- and citrus-type scent chemicals from cleaning products and fragrances rose with the number of children at home (3-carene median 0.9 to 2.5 µg/m³); the authors attribute this to more cleaning.
Moderate evidence: Late-1990s, small subgroups, attribution to cleaning is the authors' inference; CEFIC-LRI co-funded.
Source: Edwards 2006, Atmospheric Environment Industry-funded Link to this fact
Indoor air / Review of other studies
EU researchers attributed large swings in home limonene levels within the same city to whether people had used a fragrance, air freshener, or cleaning product before the air was sampled.
Moderate evidence.
Caveats
Authors' interpretation of variance; a larger, more rigorous 60-home UK diary study (Heeley-Hill 2021) found cumulative product-use frequency has little predictive power for measured concentrations (R²<0.001), with only weak covariance between limonene and insecticide/plug-in-air-freshener use specifically, not general fragrance/cleaning-product use Note the exposure measures differ: this claim concerns product use shortly before sampling, whereas Heeley-Hill 2021 tested cumulative use frequency over the sampling period, so it does not directly test the claim. Evidence is mixed: Wang 2017 (25 UK homes) found the highest-limonene homes were heavy product users; Heeley-Hill 2021 (60 UK homes; fieldwork funded by Givaudan, a fragrance manufacturer; analysis by the University of York) found frequency predicted little.
Source: Sarigiannis 2011, Environment International Link to this fact
Indoor air / Review of other studies
The standard week-long air tests used across Europe miss the short spikes of chemicals released after cleaning, which could change the risk picture for eye and airway irritation.
Moderate evidence: Authors' methodological caveat, not a measured result.
Source: Sarigiannis 2011, Environment International Link to this fact
Indoor air / Measured in people or real products
Indoor ozone reacts with the natural oils on our skin. In a test room with four people and 35 ppb ozone, this alone kept highly reactive hydroxyl (OH) radicals at about 7×10⁵ per cm³, similar to levels measured in empty rooms after cleaning with pine or citrus products.
Moderate evidence.
Caveats
High-ozone condition (35 ppb, 3.2 air changes/h, mixing fans that push ozone uptake to the top of the literature range); at the typical ~5 ppb indoor ozone the authors' model gives ~3×10⁴, 25–30× less. The companion ES&T paper (Zannoni 2021) replicates the OH-reactivity side (8–11 → 25–35 s⁻¹, ozone 85% of variance) but tested ozone only on/off, not a dose-response, and reports a geranyl acetone → 6-MHO inlet artifact that may overstate 6-MHO's share. No fragrance or health outcome studied. The ICHEAR protocol paper (Bekö 2020) shows the underlying skin-oil chemistry (6-MHO, geranyl acetone, 4-OPA) is reproducible across five groups spanning teenagers to seniors, but it reports no OH concentration data itself, so the 7×10⁵ cm⁻³ figure still rests on only the original three adult groups; it also found isoprene — the basis of this paper's alternative "precursor-product" OH cross-check — has poor day-to-day repeatability independent of the clothing explanation offered for the two methods' 1.7× disagreement.
Indoor air / Measured in people or real products
Cleaning with a pine-oil or citrus cleaner raised scent chemicals (limonene, terpinolene, alpha-terpineol) to about 1,000-6,000 ug/m3 for the first hour in a room-sized chamber, and some stayed elevated for many hours afterwards.
Moderate evidence: Empty chamber; one product per formulation; alpha-terpineol's persistence depends on surface water films and towels left in the room.
Source: Singer 2006, Indoor Air, Indoor Air Link to this fact
Indoor air / Measured in people or real products
Leaving used paper towels in the room after cleaning increased the solvent and scent chemicals released by 35-100%.
Moderate evidence: Measured over 24 h in an empty chamber.
Source: Singer 2006, Indoor Air, Indoor Air Link to this fact
Indoor air / Measured in people or real products
A limonene-cleaning event needs indoor ozone above roughly 5 parts per billion to trigger a detectable burst of new ultrafine particles; below that threshold, in this study's controlled trials, essentially no particle formation occurred.
Moderate evidence.
Caveats
One product, one 140 m3 lecture theater, one air-exchange rate (1.08/h); threshold is specific to this detergent's limonene loading and may not generalize to other products or rooms.
Source: Morawska 2009, Environmental Science & Technology Link to this fact
Indoor air / Measured in people or real products
The UK home with the heaviest, most frequent use of cleaning and fragranced products (9 different products, some used more than 10 times in a week, plus a scented candle) had a 5-day average D-limonene concentration of up to 1,439 ug/m3, around 80 times the study's median home and possibly the highest domestic value reported in the literature at the time.
Moderate evidence: Single home out of 25 driving the extreme; 5-day average, not a short-term peak, which the authors state was likely higher.
Source: Wang 2017, Environmental Science: Processes & Impacts Link to this fact
Indoor air / Measured in people or real products
Even with daily diary records of exactly how often 60 households used 13 different types of scented and cleaning products over three days, how often people used these products did not predict how much VOC was in their home's air (R-squared less than 0.001 for total VOC; no individual VOC, including limonene, showed a significant relationship).
Moderate evidence: Frequency of use, not dose per use or product formulation, was recorded; a narrow, weak exception existed for limonene with insecticide/plug-in-air-freshener use specifically.
Source: Heeley-Hill 2021, Environmental Science: Processes & Impacts Industry-funded Link to this fact
Indoor air / Other evidence
Methacrolein, a reaction product of ozone and isoprene (a natural component of human breath), can form indoors or in the airway itself whenever an ozone source is present, with no fragrance or cleaning product needed.
Moderate evidence.
Caveats
The formation reaction itself is not measured in this paper; it is cited as the motivation for the study. Later chamber work (Zannoni 2022) directly measured methacrolein forming from breath isoprene + indoor OH radicals in an occupied, product-free room.
Source: Larsen & Nielsen 2000, Toxicology Letters Industry-funded Link to this fact
Indoor air / Other evidence
The one real-world indoor measurement of gas-phase methacrolein in the wiki (309 ng/m3, during ozone-terpene cleaning-product chemistry) sits about 2,800 times below this paper's own proposed occupational exposure limit for methacrolein, and about 96,000 times below the mouse RD50.
Moderate evidence.
Caveats
Compares an acute, occupational-limit-oriented mouse endpoint to a short measured cleaning-event concentration in one test house; not a chronic or population exposure estimate. See contradictions register C63.
Source: Larsen & Nielsen 2000, Toxicology Letters Industry-funded Link to this fact
Indoor air / Self-reported survey
In a small (n=69) follow-up of Atlanta-area adults with chemical hypersensitivity, the products most commonly reported to trigger symptoms were cleaning agents (88.4%), pesticides (81.2%) and perfume (81.2%), followed by tobacco smoke (82.6%) and car exhaust (72.5%).
Moderate evidence: Small, non-random follow-up sample (n=69, about 35% of the original 199 hypersensitive respondents); self-report of trigger identification, not exposure measurement.
Source: Caress & Steinemann 2003 (EHP), Environmental Health Perspectives Link to this fact
Indoor air / Self-reported survey
The 11 household chemical products in this UK cohort's prenatal composite exposure score were used, in descending order of prevalence, as follows: disinfectant (87%), bleach (85%), aerosols (72%), air fresheners (68%), window cleaner (61%), carpet cleaner (36%), paint or varnish (33%), turpentine/white spirit (23%), pesticides/insect killers (21%), paint stripper (6%) and dry-cleaning fluid (5%).
Moderate evidence.
Caveats
Descriptive prevalence data, not an effect estimate. The 11 products were selected from an initial list of 15 by keeping only those used by at least 5% of the study sample, so rarer products are excluded from the score.
Indoor air / Measured in people or real products
Ordinary indoor ozone reacts with the natural oils on everyone's skin (mainly squalene) to produce a family of carbonyl and dicarbonyl air pollutants — with no fragrance, cleaning product, or air freshener needed. In a simulated two-person office at everyday occupied-room ozone levels (14-18 ppb), two of the compounds (6-MHO and 4-oxopentanal) reached 0.5-2.3 ppb.
Moderate evidence: Single research group; a small 28.5 m3 chamber with only 2 occupants, not a real home; concentrations scale with occupancy and ozone level.
Source: Wisthaler & Weschler 2010, Proceedings of the National Academy of Sciences Link to this fact
Indoor air / Measured in people or real products
After adjusting for outdoor PM2.5, season, cooking, cleaning, and smoking, incense-burning events were the largest contributor to indoor PM2.5 among all monitored indoor activities in 32 Hanoi homes, raising the geometric mean of total indoor PM2.5 by 120.3% (versus +71.6% for cooking, +52.2% for smoking, +40.5% for cleaning).
Moderate evidence: Single-city, single-cohort study with no independent replication; percentages are specific to this sample's burn frequency, ventilation, and background air quality.
Source: Tran 2021, Building and Environment Link to this fact
Indoor air / Other evidence
In a small case series, removing mothballs and reducing scented cleaning/personal-care products, candles, and stored chemicals cut targeted indoor-air VOC categories by roughly a quarter to over 95% (e.g., naphthalene from mothballs down 96%, p-dichlorobenzene from moth crystals down 56-80%, odorants/fragrances down 26-80%) across three homes, measured by GC/MS air sampling before and after a structured home intervention.
Moderate evidence.
Caveats
Small, uncontrolled, non-blinded case series with multiple co-occurring intervention elements per home (product substitution, education, counseling, and in one case new chemical storage); cannot isolate the VOC-reduction effect from other changes.
Source: Rincón et al. 2024, Primary Health Care Research & Development Link to this fact
Indoor air / Measured in people or real products
Hotel housekeepers' real occupational personal exposure to fragrance terpenes (mainly limonene and alpha-pinene) from direct, repeated contact with cleaning and laundry products averaged just 7.7 µg/m3, even though every cleaning product tested in the study contained terpenes (up to 64 µg/mL in one smoke-removal spray).
Moderate evidence: Occupational, not general-population exposure; short sampling window (6-9h); small sample.
Indoor air / Measured in people or real products
In this hotel study, airborne formaldehyde — the single biggest driver of estimated health risk — did not track terpene-fragrance levels or season (terpene-ozone secondary chemistry would be expected to rise with summer ozone), leading the authors to attribute it instead to building materials, furnishings, and the large volume of bedding and towels used in hotels, not to the terpene-containing cleaning and laundry products.
Moderate evidence: Attribution is inferential, not source-tested directly; the authors call for further study to verify formaldehyde sources in hotels.
Indoor air / Measured in people or real products
In a 2021 pilot study of 20 real nail salons in the NYC area, toluene (median 7.03 ppb) and d-limonene (median 4.21 ppb) were the two most abundant of 31 volatile organic compounds measured in the air, and the authors attribute the d-limonene to cleaning and disinfection products rather than nail products, since d-limonene is not a nail-product ingredient.
Moderate evidence.
Caveats
Small convenience sample (n=20), area/micro-environmental air sampling only (not personal exposure), sampled during COVID-19 when cleaning frequency was likely elevated; source attribution to cleaning products is the authors' inference, not measured (no product-ingredient data collected).
Source: Han et al. 2022 Link to this fact
Indoor air / Measured in people or real products
Nail salons serving 30 or more customers per day had significantly higher air d-limonene (median 6.18 ppb) than salons serving fewer than 30 customers (median 2.30 ppb, p=0.044), consistent with more frequent cleaning of tables between customers.
Moderate evidence: Single small pilot study; cleaning-product use itself was not directly measured or recorded, only inferred from customer volume and observed cleaning behavior.
Source: Han et al. 2022 Link to this fact
Indoor air / Other evidence
Ordinary spray-and-wipe cleaning with quats, bleach, hydrogen peroxide, or a thymol-based botanical disinfectant raised indoor fine-particle (PM2.5) levels by 0.7-14.5 micrograms per cubic meter and total-VOC sensor readings by 10-104 ppbv, measured across a residential bathroom, a university office, two chemistry labs, and a hotel in Canada.
Moderate evidence: Single study, small replicate counts per cleaner/location, and the TVOC sensor is explicitly non-quantitative.
Source: Souza 2025, ACS Earth Space Chem, ACS Earth and Space Chemistry Link to this fact
Indoor air / Other evidence
The lowest-ventilation room tested, a residential bathroom with an air change rate under 1 per hour, showed 146-346% higher cleaning-related PM2.5 increases and about 7-fold higher TVOC increases than a university office and lab with 5.9-9.1 air changes per hour, for the same cleaning products.
Moderate evidence: One bathroom, one office, two labs; not a dose-response series across many ACR values.
Source: Souza 2025, ACS Earth Space Chem, ACS Earth and Space Chemistry Link to this fact
Indoor air / Other evidence
The particulate matter released during cleaning in this study looked like direct, mechanical spray-bottle emission rather than new particles forming from chemical reactions in the air, consistent across all four very different cleaning chemistries tested.
Moderate evidence.
Caveats
No ozone was deliberately added or measured in these experiments, and none of the four products was a terpene-rich scented cleaner, so this does not rule out secondary particle formation under different (ozone-rich, terpene-rich) conditions documented elsewhere.
Source: Souza 2025, ACS Earth Space Chem, ACS Earth and Space Chemistry Link to this fact
Indoor air / Other evidence
Bleach cleaning produced a two-humped (bimodal) rise in total VOC readings, a pattern consistent with bleach's chlorine-based oxidants reacting with ordinary indoor VOCs to form new, oxidized compounds, rather than only releasing VOCs directly.
Moderate evidence: The oxidized compounds were not chemically identified in this study; the PID gives only a total, non-specific VOC signal, so this is an inferred mechanism, not a confirmed one.
Source: Souza 2025, ACS Earth Space Chem, ACS Earth and Space Chemistry Link to this fact
Indoor air / Other evidence
During real COVID-19 disinfection at a hotel, repeated use of a quats-based disinfectant raised fine-particle levels by 5.5 to 14.2 micrograms per cubic meter in the lobby, elevator, and a public bathroom, exposing cleaning staff to repeated particle bumps throughout a work shift.
Moderate evidence.
Caveats
One day of field measurement, one hotel; cleaning protocol there also deviated from the product label (solution left on surfaces rather than wiped off) to reduce staff vapor exposure.
Source: Souza 2025, ACS Earth Space Chem, ACS Earth and Space Chemistry Link to this fact
Indoor air / Other evidence
A 2011 Georgetown study that sent test fabrics through seven Northern Virginia dry cleaners found perchloroethylene (PCE) solvent still in polyester, wool, and cotton after one cleaning at all five shops that use PCE, about 10-57 nmol/cm2 depending on fabric and shop.
Moderate evidence.
Caveats
One jacket and one cleaning per shop, unpressed swatches sewn into the lining, seven shops in one region; residue measured, not what anyone breathes or absorbs. No industry funding stated.
Source: Sherlach 2011, Environmental Toxicology and Chemistry Link to this fact
Indoor air / Other evidence
In a lab chamber with a very high ozone level (about 6.5 ppm), all six ordinary perfumes, deodorants and cleaning liquids tested formed new particles; about 0.2% to 17% of the product's evaporated mass became aerosol, with an average near 4%.
Moderate evidence.
Caveats
One lab, six products, a closed 0.68 m3 chamber at roughly 100 times typical indoor ozone, very dry air, no vapor wall-loss correction; a yield, not an indoor concentration. NSF and Sloan funded; no industry funding.
The industry / Industry source
Even after this 2017 update, the fragrance industry's own aggregate exposure model still explicitly excluded household cleaning and laundry products — the product category the industry's own 2003 safety-process paper says accounts for about 60% of fragrance volume — and named their inclusion as future work.
Moderate evidence.
Caveats
Single industry methods paper describing its own model's scope; the gap was closed industry-wide only in a later 2024 paper (Lee et al.), which this claim's caveat should be read alongside.
Source: Comiskey 2017 (RIFM/Creme Global), Regulatory Toxicology and Pharmacology Industry-funded Link to this fact
The industry / Measured in people or real products
Tumble dryer manufacturers give directly conflicting instructions on cleaning the lint filter: some tell consumers to rinse it under water, others recommend a dishwasher, others dry methods only, and one (John Lewis) explicitly says never use water, for environmental reasons.
Moderate evidence: One UK market snapshot (24 brands, January 2023), not checked against other countries or against what consumers actually do.
Source: Cummins 2023, PLOS ONE Industry-funded Link to this fact
The industry / Government agency
Benzophenone is widely used as a UV-curing photoinitiator for inks and varnishes, a fragrance fixative/enhancer and flavoring agent, a UV blocker in plastic packaging, and an additive in coatings, adhesives, laundry and household cleaning products; the US EPA classified it a high-production-volume chemical in 2003, with US annual production exceeding 1 million pounds (453,000 kg).
Moderate evidence: Production/use figures are the Working Group's synthesis of industry and HSDB/NTP secondary sources, not independently verified primary measurement.
Source: IARC 2013 Link to this fact
The industry / Measured in people or real products
All cleaning products tested in this study (laundry detergent, fabric softener, dust/floor/glass cleaners, and a smoke remover) contained detectable VOCs; alkanes (mainly n-tetradecane, 87 µg/mL in the laundry detergent) and terpenes (mainly limonene, up to 64 µg/mL in the smoke-remover spray) were the dominant classes, while chlorine bleach (not itself tested for VOCs but used liberally) was linked to the chloroform and carbon tetrachloride found in laundry-room air.
Moderate evidence: Only 7 products from one hotel were tested; formulations vary by brand and hotel.
The industry / Review of other studies
The 2016 review of clothing-cleaning methods was funded by Australian Wool Innovation, the wool industry's research body, and a coauthor works there; wool is the fiber it says needs more research on wet cleaning.
Moderate evidence.
Caveats
Funding by a fiber-growers body, not a solvent maker; no competing-interest statement beyond the funding line. This is a disclosure of potential interest, not evidence of bias in any specific finding.
Source: Troynikov 2016, Journal of Environmental Management Industry-funded Link to this fact
Laws and loopholes / Review of other studies
Fewer than half (46.0%) of 63 reviewed fragrance-free policies included any supply-chain or procurement control over the cleaning, laundry, or air-freshening products the institution itself buys, even though named triggers in the companion focus-group study rank cleaning and laundry products alongside or above perfume.
Moderate evidence: Document analysis; does not establish that procurement control would reduce measured exposure, only that most policies do not attempt it.
Laws and loopholes / Government agency
HUD's own Occupancy Handbook (4350.3 REV-1, Exhibit 2-6, June 2007) states that for a HUD-assisted housing resident with chemical sensitivity disorder, it is not an undue financial and administrative burden for the owner to give advance notice before cleaning common areas and to use nonchemical alternative cleaning methods where practical.
Moderate evidence.
Caveats
Binding operational guidance for HUD-assisted multifamily housing, not a court ruling; applies only to owner-controlled common-area cleaning, not to other tenants' or staff's personal fragrance/scent use, and 'where practical' is left case-by-case.
Source: HUD Occupancy Handbook 4350.3 REV-1, Exhibit 2-6 (2007) Link to this fact
Laws and loopholes / Other evidence
EWG Verified counts fragrance in its VOC limits and does not use California's fragrance exemption (0.25 percent by weight for several cleaner categories from 2031).
Moderate evidence: Program rule, not a measured emission result; compares a voluntary standard with California's regulation.
Source: EWG Verified criteria for cleaning products (10.24), Environmental Working Group, 2024 Link to this fact
Laws and loopholes / Other evidence
In 2012 US law required ingredient labels on food, cosmetics, and drugs but not on household cleaning products, according to EWG.
Moderate evidence: Stated by an advocacy group without citation; the legal position since 2012 has changed in some states, so date the claim.
Source: EWG press release, Sept. 10, 2012, EWG press release (web page) Link to this fact
Laws and loopholes / Other evidence
Suffolk County Local Law 15-2016 required the county health department to build a consumer-facing system categorizing garment-cleaning solvents; US EPA will no longer allow perchloroethylene cleaners to operate in residential buildings after 2020, and New York already requires closed-loop machines.
Moderate evidence: Describes law as the report states it in 2018; later regulatory changes were not checked.
Source: SCDHS 2018 Link to this fact
Skin allergy / Measured in people or real products
In industry's own comparative testing of 24 household cleaning-product formulations, liquid and powder laundry and dish detergents ranked among the least skin-irritating categories tested, below a standard 20% SDS irritant benchmark (liquid laundry detergent TR50 average 3.48 h; powder laundry and dish detergents >16 h, vs. SDS's 1.81 h).
Moderate evidence.
Caveats
Irritation (erythema from a single undiluted, fully occluded 4-h exposure), not allergy; single industry-funded study series with no independent replication; authors state results should not be extrapolated to real-use exposure conditions.
Source: Robinson et al. 2005, Food and Chemical Toxicology Industry-funded Link to this fact
Skin allergy / Other evidence
Household detergents and cleaners were preserved with MI far more often than cosmetics in two European surveys: 16 of 97 Swedish detergents (16.5%) against 1 of 204 cosmetics, and 30 of 291 Italian cleaning products (10.3%).
Moderate evidence: Secondary summary of ingredient-label surveys from about 2009-2010; counts are small and not recent.
Source: Lundov 2011, British Journal of Dermatology Link to this fact
Skin allergy / Other evidence
US dermatologists' society review: fragrance was the 2007 Allergen of the Year; the industry's RIFM database lists more than 2,800 fragrance ingredients, at least 100 of them known allergens, and fragrance allergens can be hidden in cleaning and cosmetic products, even ones marketed as fragrance free.
Moderate evidence: Narrative review relaying other papers' statements; no original data and no counts of products.
Source: Militello 2020, Dermatologic Clinics Link to this fact
Skin allergy / Other evidence
EWG Verified cleaners must label 26 fragrance allergens on the package at 0.01 percent (0.001 percent for hand dish soap, hand laundry detergent, and leave-on pet products), and post about 57 more on the product website.
Moderate evidence: The on-pack list is the pre-2023 EU 26; current EU cosmetics law requires about 80 on pack. The website list has a one-year phase-in and EWG reserves a transition period.
Source: EWG Verified criteria for cleaning products (10.24), Environmental Working Group, 2024 Link to this fact
What you can do / Measured in people or real products
Researchers recommend lower-terpene (less citrus/pine-scented) cleaners, diluting them, ventilating during and for hours after cleaning, cleaning when fewer people are home, and never running ozone generators or ionizers with these products.
Moderate evidence: Author recommendations derived from chamber chemistry, not tested as interventions.
Source: Singer 2006, Atmospheric Environment Link to this fact
What you can do / Self-reported survey
Fragrance-free policies need to cover cleaning and laundry products, not just perfume: of 60 people who react to fragranced products, 50 named cleaning products, 47 perfume, and 41 laundry products as persistent triggers.
Moderate evidence: Self-selected Canadian sample (90% female); counts of participants naming a source, not exposure measurements.
Source: Roy 2026 Link to this fact
What you can do / Self-reported survey
Fragrance-free health-care policies should cover cleaning and laundry products, not just staff perfume; Canadian advocates ask for exactly this, and people who react name cleaning products as their most common trigger (50 of 60).
Moderate evidence: Advocacy position plus a self-selected focus-group sample; no evidence yet that policies reduce exposure or symptoms.
What you can do / Measured in people or real products
How much formaldehyde and particle pollution formed was set mainly by how much ozone was available, not by how much product was used, so running an ozone-generating air purifier or ionizer alongside scented cleaning products or air fresheners adds directly to indoor formaldehyde and particles.
Moderate evidence: Conclusion drawn from controlled chamber chemistry (ozone as the limiting reagent in every run), not tested as a real-world intervention.
Source: Destaillats 2006, Environmental Science & Technology Link to this fact
What you can do / Measured in people or real products
Take used paper towels, sponges, and mop water out of the room right after cleaning, ventilate during and after, and choose cleaners without 2-butoxyethanol (ethylene glycol monobutyl ether / butyl cellosolve on the label or SDS); avoid running ozone generators with terpene-scented products.
Moderate evidence: Author recommendations derived from chamber chemistry, not tested as interventions.
Source: Singer 2006, Indoor Air, Indoor Air Link to this fact
What you can do / Measured in people or real products
In a study of 25 UK homes, easy-to-check building factors (home age, size, number of occupants, single- vs double-glazing) showed no measurable relationship to indoor scent-chemical levels; the homes with the highest levels were those whose occupants reported heavy cleaning/fragrance-product use.
Moderate evidence.
Caveats
Glazing comparison used t-tests on 19 homes with no ventilation-rate data; product-use link is a qualitative activity-log correlation, not a controlled experiment A larger same-lab study (Heeley-Hill 2021, 60 UK homes, daily diaries; Givaudan-funded fieldwork) found cumulative product-use frequency had almost no predictive power for measured VOC levels (R²<0.001), so treat the product-use link as suggestive.
Source: Wang 2017, Environmental Science: Processes & Impacts Link to this fact
What you can do / Self-reported survey
During pregnancy, prefer pouring or wiping cleaning products rather than spraying them, and limit solvent and air-freshener use, since spray application was the exposure most consistently linked to infant respiratory symptoms across this and sibling cohort studies.
Moderate evidence.
Caveats
Based on an observational association, not a controlled trial; the authors' own explanation (spraying increases inhaled dose of both volatile and non-volatile components) is plausible but unproven.
Source: Casas 2013, International Journal of Public Health Industry-funded Link to this fact
What you can do / Other evidence
Treat a strong, persistent solvent-type smell (heavy cleaning, fresh paint, new furnishings in a poorly ventilated space) as a plausible trigger for eye, nose, throat, or mild respiratory irritation, and ventilate or leave the area if symptoms appear.
Moderate evidence: The doses tested were far higher than most ventilated homes reach; this advice is about avoiding irritant symptoms, not about a demonstrated injury risk from ordinary indoor air.
Source: Pappas et al. 2000, Int J Occup Environ Health 6:1-8 Link to this fact
What you can do / Review of other studies
Never mix chlorine bleach with ammonia or acidic cleaning products, since this releases chlorine gas or trichloramine, both strong respiratory and eye irritants documented to cause acute lung injury in cleaners and housewives.
Moderate evidence: Drawn from background literature the authors cite (occupational case reports and reviews), not from new data collected in this study.
Source: Nickmilder, Carbonnelle & Bernard 2007, Pediatric Allergy and Immunology Link to this fact
What you can do / Review of other studies
When relying on a workplace, clinic, or school's fragrance-free policy, check whether it (1) defines what's covered beyond perfume, especially cleaning and laundry products, (2) sets a default fragrance-free expectation rather than a complaint-triggered one, (3) controls what cleaning/laundry products the institution buys, and (4) names a real consequence for non-compliance — a 2026 scoping review of 63 such policies found these structural features present in well under half of cases.
Moderate evidence: Based on a gray-literature document review of North American policies; individual policies may vary, and having these features on paper does not guarantee enforcement.
What you can do / Government agency
A resident of HUD-assisted housing with a documented chemical sensitivity can cite this HUD exhibit directly when requesting advance notice before common-area cleaning and nonchemical cleaning products where practical, since HUD's own guidance names these as accommodations that are not an undue burden.
Moderate evidence.
Caveats
Applies specifically to HUD-assisted (Section 504-covered) multifamily housing; the same specific accommodations are not guaranteed at privately owned housing covered only by the Fair Housing Act, where the undue-burden analysis is done case by case.
Source: HUD Occupancy Handbook 4350.3 REV-1, Exhibit 2-6 (2007) Link to this fact
Information, not medical advice. See also: myths we won’t tell you.