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.
Children and pregnancy / Measured in people or real products
Childcare air had about three times more limonene than new California homes (33 vs 11 µg/m³), which the authors link to frequent cleaning.
Moderate evidence: Comparison with a different study (Offermann 2009); daytime vs 24-h sampling.
Children and pregnancy / Self-reported survey
Mothers who use cleaning sprays during pregnancy have infants with higher odds of both a lower respiratory tract infection (29% higher, OR 1.29) and wheezing (37% higher, OR 1.37) in their first year of life, in a pooled analysis of four Spanish birth cohorts (n=2,292); prenatal solvent use also raised wheezing odds (30% higher) and prenatal air freshener use raised LRTI odds (29% higher).
Moderate evidence.
Caveats
Single research group/dataset (pooled INMA cohorts, all Spanish, one study design), self-reported exposure and outcome by mothers, and only 12-18 month follow-up (no atopy or physician-diagnosed asthma measured). Consistent in direction with two other independent cohorts (Parks 2020, Canada; Mikeš 2019, Czech Republic) that measured early-postnatal rather than prenatal exposure, which is why the combined three-cohort claim is graded strong elsewhere while this single-paper prenatal-specific finding stays moderate.
Source: Casas 2013, International Journal of Public Health Industry-funded Link to this fact
Children and pregnancy / Self-reported survey
In a random sample of Swedish teenagers aged 13-19, about 1 in 6 (15.6%) said they were bothered by strong odors such as perfume, cleaning agents, or flower scents, most often affecting the nose.
Moderate evidence: Single-item self-report; general odor sensitivity, not fragranced-product-specific; one Swedish town.
Source: Andersson 2008, International Journal of Hygiene and Environmental Health Link to this fact
Children and pregnancy / Measured in people or real products
The protective association between bleach cleaning and reduced allergy/asthma risk was abolished in households with parental smoking; in that subgroup, bleach use was instead linked to a higher rate of recurrent bronchitis (adjusted OR for the smoking-by-bleach interaction, 2.03, 95% CI 1.12-3.66).
Moderate evidence: Subgroup/interaction analysis from a single cross-sectional study; the recurrent-bronchitis outcome is parent-reported, not medically confirmed.
Source: Nickmilder, Carbonnelle & Bernard 2007, Pediatric Allergy and Immunology Link to this fact
Children and pregnancy / Self-reported survey
In a Dutch birth cohort of 2,333 adolescents (age 14), a composite score for household use of 10 types of cleaning agents was not associated with asthma, rhinitis, or eczema, even at the highest exposure quartile: adjusted OR (95% CI) 0.95 (0.56, 1.63) for asthma, 1.23 (0.83, 1.82) for rhinitis, and 0.95 (0.56, 1.63) for eczema, comparing highest to never/seldom use.
Moderate evidence.
Caveats
Cross-sectional, single cohort, parent-reported exposure and outcomes; adolescents are not the ones doing the cleaning, so this speaks to a low-exposure life stage rather than ruling out effects at higher exposure (e.g. prenatal/infancy).
Source: Bukalasa et al. 2019, Environment International Link to this fact
Children and pregnancy / Self-reported survey
A sensitivity analysis restricted to the 988 adolescents (42% of the cohort) reported to be sometimes or mostly present at home during cleaning activities again found no association between the composite cleaning-agent-use score and asthma, rhinitis, or eczema, confirming the main null result.
Moderate evidence.
Caveats
Smaller subsample (n≈988) with wider confidence intervals; one rhinitis point estimate for the low-exposure category rose to adjusted OR 2.14 (95% CI 1.04, 4.41) without a dose-response pattern across categories, which the authors do not treat as a real effect.
Source: Bukalasa et al. 2019, Environment International Link to this fact
Fragrance is everywhere / Review of other studies
In California's 1997 inventory, air fresheners were the single largest category of cleaning-product chemical emissions: 7.5 metric tons a day, just ahead of general-purpose cleaners.
Moderate evidence: 1997 sales-based inventory; later SoCAB inventory had air fresheners <2.5 t/d.
Source: Nazaroff & Weschler 2004, Atmospheric Environment Link to this fact
Fragrance is everywhere / Measured in people or real products
Scented product categories (personal care and cleaning) made about half of the ozone from consumer and industrial chemical products in New York, mostly through their alcohol and glycol solvents rather than the fragrance molecules.
Moderate evidence: Box-model budget, one city/episode; 'fragranced VCP' is a product category: fragrance compounds are ~6% of VCP ozone, oxygenates 24%, and ethanol 15%.
Source: Coggon 2021 Link to this fact
Fragrance is everywhere / Self-reported survey
In a 1995 population-based telephone survey of 4,046 California adults, 15.9% said they were 'allergic or unusually sensitive to everyday chemicals' (like cleaning supplies, paints, perfumes, or soaps) and 6.3% reported a doctor's diagnosis of environmental illness or multiple chemical sensitivity.
Moderate evidence.
Caveats
Self-report only, no clinical verification of diagnosis or symptoms; California-specific, not national; the study's own authors take no position on whether this reflects a real physiologic condition or societal apprehension about chemicals.
Source: Kreutzer, Neutra & Lashuay 1999, American Journal of Epidemiology Link to this fact
Fragrance is everywhere / Other evidence
In a 2016 barcode-scan inventory of 2,963 household products from 131 German homes, EU-regulated biocidal active substances (preservatives, disinfectants, insecticides, repellents) were found in every single household, and personal care products plus washing/cleaning agents accounted for 90% of all such ingredient observations, far outnumbering the biocidal products the regulation is actually built around.
Moderate evidence.
Caveats
German sample; convenience sampling in 2 of 3 neighborhoods (response rate not calculable there); 65% response rate in the rural site; ingredient-list presence, not measured wastewater concentration or biological exposure.
Source: Wieck 2016, Environment International Link to this fact
Fragrance is everywhere / Other evidence
Researchers found multiple fragrance sources (cosmetics, air fresheners, cleaning/laundry products, fragrance-emitting devices, or candles) in every one of the 37 homes they surveyed for a chemical-intolerance study.
Moderate evidence.
Caveats
Sample is self-selected chemical-intolerance patients recruited from a specialty clinic, not a general-population sample; fragrance ubiquity may be overrepresented relative to the general population's home inventories.
Source: Rincón et al. 2024, Primary Health Care Research & Development Link to this fact
Fragrance is everywhere / Other evidence
Perchloroethylene in Suffolk County groundwater: not detected in about 92% of supply wells sampled 2009-2013, but found in three times as many wells in 2013 as in 1987 with the average concentration doubled; public-supply maximum 93 ppb against a 5 ppb limit, and orders of magnitude higher at dry-cleaning sites.
Moderate evidence: Local county data summarized second-hand; trend reflects the wells sampled and is not attributed to dry cleaning alone.
Source: SCDHS 2018 Link to this fact
Green, natural and unscented / Journalism
Green-claim auditors named 'all-natural' as a textbook example of a vague green claim and called household cleaning-product makers 'among the worst greenwash offenders'.
Moderate evidence: Opinion of TerraChoice staff; '3 of 397 cleaners' figure not text-verified.
Source: Dahl 2010, Environmental Health Perspectives Link to this fact
Green, natural and unscented / Measured in people or real products
In a chamber test of 30 US cleaning products and air fresheners, fragrance-free green cleaners gave off significantly fewer volatile chemicals than conventional ones: about 500 vs 4,700 ug/m3 total on average (approx., read from Fig. 4A), and about 6 vs 46 distinct VOCs per product (approx., read from Fig. 4D).
Moderate evidence.
Caveats
EWG-authored (advocacy nonprofit that ranks cleaners and licenses EWG VERIFIED to cleaner makers); Skyline Foundation grant; unblinded; 7 fragrance-free vs 14 conventional products, one product per brand, single lab; green products also applied less product per use; chamber concentration, not personal exposure. Group means are read from Fig. 4.
Health effects / Review of other studies
Cleaning products were the suspected exposure in 236 of 1,915 (12%) confirmed work-related asthma cases across California, Massachusetts, Michigan, and New Jersey (1993-1997); in California, janitors and cleaners had roughly double the confirmed-case rate of all other occupations combined (4.3 vs 2.3 per 100,000 workers).
Moderate evidence.
Caveats
Now traced to its primary source (Rosenman 2003), not a secondary citation. But the underlying surveillance system's own authors say it misses 53-87% of true cases (Michigan capture-recapture) and that up to 37% of confirmed cases in such systems may not be truly work-related (Malo et al., cited by Rosenman); 'cleaning products' is a broad, mostly unspecified chemical category (36% of named agents never identified further than 'cleaning compound'), not fragrance-specific (limonene only 2/300 exposure counts).
Source: Nazaroff & Weschler 2004, Atmospheric Environment Link to this fact
Health effects / Measured in people or real products
In a Toronto clinic for work-related breathing problems, about 1 in 10 referred workers had an irritable larynx (throat) syndrome rather than asthma; perfumes and cleaning agents, bleaches and air fresheners were among the named triggers.
Moderate evidence.
Caveats
Single referral clinic, retrospective, n=30; perfume named by 5/30 and cleaning agents/fresheners by 4/30; 10% of referrals, not of workers. Morrison 1999, the founding case series behind the diagnostic criteria Hoy applied, independently found perfume was a named trigger in only 26% (10/39) of its own ILS cohort, behind reflux (72%) and other airborne irritants (51%) — the syndrome is not fragrance-specific at its point of origin either.
Health effects / Self-reported survey
In the same 2016 US survey, about 1 in 4 adults (25.9%) said they were unusually sensitive to everyday chemicals such as cleaning products, perfume, and detergents, and 81% of them reported health problems from fragranced products.
Moderate evidence: Self-report; adults 18-65 in an opt-in online panel; earlier US telephone surveys gave 11-16%.
Source: Steinemann 2018 (JOEM), Journal of Occupational and Environmental Medicine Link to this fact
Health effects / Measured in people or real products
Cleaning products were the suspected exposure in 236 of 1,915 (12%) confirmed work-related asthma cases across California, Massachusetts, Michigan, and New Jersey, 1993-1997; most were new-onset asthma (80%) and about a fifth were consistent with reactive airways dysfunction syndrome, an irritant-induced, non-allergic asthma type.
Moderate evidence.
Caveats
This is a primary surveillance source, not a population prevalence estimate: the authors' own capture-recapture analysis found the surveillance system misses 53-87% of true work-related asthma cases in Michigan, and up to 37% of confirmed cases in such systems may not be truly work-related (Malo et al., cited by the authors). Fragrance/limonene was a minor named agent (2 of 300 exposure counts); bleach, acids, disinfectants, and quaternary ammonium compounds dominate.
Source: Rosenman 2003, Journal of Occupational and Environmental Medicine Link to this fact
Health effects / Self-reported survey
In a large random sample of Swedish adults (Vasterbotten, n=3,406), 12.2% said they get symptoms from odorous or pungent chemicals such as perfumes and cleaning agents in doses that don't bother most other people, but only 3.3% had actually been given a doctor's diagnosis of a chemical-intolerance condition.
Moderate evidence: Single region (Vasterbotten county), not national; diagnosis status is itself self-reported, not verified against medical records.
Source: Palmquist 2014, International Journal of Hygiene and Environmental Health Link to this fact
Health effects / Self-reported survey
In a 2002-03 US national telephone survey of 1,054 randomly selected adults, 11.2% self-identified as unusually sensitive to everyday chemicals such as cleaning products, perfume, and detergents, and 2.5% said they had been medically diagnosed with multiple chemical sensitivity (MCS).
Moderate evidence.
Caveats
Single national random-digit-dial telephone survey; self-report with no clinical verification of hypersensitivity or diagnosis; the earliest in a cross-country series of self-report chemical-sensitivity prevalence figures.
Source: Caress & Steinemann 2003, Archives of Environmental Health: An International Journal Link to this fact
Health effects / Self-reported survey
In a 10-country European cohort of 3,503 adults who did the cleaning at home and were asthma-free at baseline, using household cleaning sprays at least once a week was associated with a 49% higher rate of new asthma symptoms or asthma-medication use over about 9 years of follow-up.
Moderate evidence: Single multinational cohort (not yet independently replicated by a different research group); exposure and symptom outcomes were both self-reported at one follow-up interview.
Source: Zock et al. 2007, American Journal of Respiratory and Critical Care Medicine Link to this fact
Health effects / Self-reported survey
Using household cleaning sprays at least 4 days a week was linked to roughly double the rate of new physician-diagnosed asthma (HR 2.11, 95% CI 1.15-3.89) compared with light or no spray use, with a clear dose-response across frequency categories (P for trend 0.041) and number of different sprays used (P for trend 0.022).
Moderate evidence: Physician-diagnosed asthma relied on participant report of a doctor's diagnosis, not independent verification; single cohort.
Source: Zock et al. 2007, American Journal of Respiratory and Critical Care Medicine Link to this fact
Health effects / Self-reported survey
Cleaning products that were not applied as a spray (liquid multiuse cleaners, washing powders, polishes, bleach, ammonia, decalcifiers) showed no significant association with new-onset asthma in this study, while glass-cleaning, furniture, and air-refreshing sprays did.
Moderate evidence.
Caveats
Correlation between spray use and other product use was generally weak but not zero (Spearman's r up to 0.41 for some product pairs), so residual confounding by broader cleaning intensity cannot be fully excluded.
Source: Zock et al. 2007, American Journal of Respiratory and Critical Care Medicine Link to this fact
Health effects / Self-reported survey
The single highest-risk activity for asthma and nasal symptoms was manual dilution of concentrated disinfectant products (adjusted OR 4.01, 95% CI 1.34-12.00 for asthma; 1.90, 95% CI 1.13-3.18 for nasal symptoms), higher than general disinfection or cleaning tasks alone.
Moderate evidence.
Caveats
Task-level self-report from a single cross-sectional study; the authors interpret this as likely reflecting dilution errors that create exposure peaks to concentrated, strongly irritant product, not a tested causal mechanism.
Source: Gonzalez 2014, Clinical & Experimental Allergy Link to this fact
Health effects / Self-reported survey
Weekly use of disinfectant/cleaning sprays at work was associated with worse asthma control in US nurses (OR 1.50, 95% CI 1.16-1.94 for poorly controlled; OR 1.38, 95% CI 1.00-1.92 for very poorly controlled), and the association held even among nurses who used sprays less than once a week.
Moderate evidence.
Caveats
Self-reported spray use; the paper attributes the effect to higher inhalation potential from spray application rather than to a specific chemical, since sprays covered multiple product types (surface, patient care, air-refreshing).
Source: Dumas 2017, European Respiratory Journal Link to this fact
Health effects / Review of other studies
Formaldehyde, released by household cleaning products both directly and via reaction with indoor ozone, is described as a human carcinogen as well as a respiratory irritant.
Moderate evidence.
Caveats
This is a background descriptive statement in an emissions-chamber study, not new primary carcinogenicity data; it does not itself cite IARC or NTP classifications by name. Corroborated separately in our evidence base by US EPA's own indoor-air VOC guidance, which states plainly that benzene is 'a known human carcinogen' (src-2026-epa-voc-impact-indoor-air-quality) — so both halves of the video's statement (benzene and formaldehyde) are independently backed by evidence base source pages, though not yet as a combined graded claim.
Source: Rossignol 2013, Atmospheric Environment Link to this fact
Health effects / Other evidence
Four cleaning occupations (unspecified cleaners, domestic helpers and cleaners, helpers/cleaners in offices and hotels, and hand-launderers) were associated with adult onset asthma in this cohort, with odds ratios from 1.58 to 2.26; the offices/hotels cleaning code (OR 1.82, 95% CI 1.34-2.48) and home-based personal care workers (OR 1.94, 95% CI 1.40-2.69) remained significant after correcting for testing 61 occupations.
Moderate evidence: Job-title-level exposure, not product-level; the lowest estimate (unspecified cleaners, OR 1.58) did not reach significance on its own (p=0.078).
Health effects / Other evidence
Using a job-exposure matrix built specifically for asthma research (ASJEM), lifetime exposure to low-molecular-weight reactive cleaning or disinfecting products was associated with 67% higher odds of adult onset asthma (OR 1.67, 95% CI 1.26-2.22), the single exposure category that remained significant after correcting for 18 tested high-risk exposures (q<0.001).
Moderate evidence.
Caveats
The ASJEM exposure category is an expert judgment covering an unspecified mix of cleaning/disinfecting chemicals, not a named ingredient; single-cohort, not yet independently replicated.
Health effects / Self-reported survey
Among the same 113 migraineurs, 90.2% had migraine crises triggered by odors, and of those, perfume was by far the most common odor trigger (95.1%), followed by cleaning products (81.3%), cigarette smoke (71.5%) and motor vehicle exhaust (70.5%).
Moderate evidence: Self-report, unvalidated questionnaire, single clinical sample, no provocation testing of the named odors.
Source: Fornazieri 2016, Headache: The Journal of Head and Face Pain Link to this fact
Health effects / Measured in people or real products
Among hotel workers directly handling cleaning products, bleach, and laundry chemicals, the average estimated excess lifetime cancer risk from inhaled VOCs (4.1 in 100,000) was about 40 times the EPA's 1-in-a-million screening threshold, driven more than two-thirds by formaldehyde (then chloroform and benzene), even though measured VOC concentrations were at the low end of those reported in US buildings generally.
Moderate evidence: Preliminary/screening-level risk estimate extrapolated from short-term (6-9h) measurements to a 40-hr workweek; small sample (2 hotels); not a measured cancer incidence.
Health effects / Measured in people or real products
Despite directly and repeatedly handling cleaning products and bleach all shift, hotel housekeepers', laundry, maintenance, and office workers' calculated non-cancer hazard ratios for VOC exposure all fell below the standard threshold of 1 (ranging 0.3-0.5 across worker groups), though all remained above the more conservative 0.1 margin-of-safety benchmark the authors mention; formaldehyde contributed most of the hazard for every group except the single maintenance worker, where a lubricant-derived alkane (n-nonane) contributed slightly more (54% vs 46%).
Moderate evidence: Preliminary screening-level estimate from short-term sampling; maintenance-worker group size n=1.
Health effects / Other evidence
In a Belgian referral clinic, 17 of 44 workers (39%) who had asthma symptoms they linked to cleaning or disinfecting products had a measurable asthmatic reaction (a sustained 20% or greater fall in FEV1) when exposed to their own work products under controlled conditions.
Moderate evidence.
Caveats
Retrospective single-center chart review of workers referred (mostly via compensation claims); not a prevalence among cleaners. No blinding described; products were commercial mixtures and exposure was not measured.
Health effects / Other evidence
Of the 17 workers who reacted to cleaning products, 10 reacted to products containing quaternary ammonium compounds (mainly benzalkonium and didecyldimethylammonium chlorides), 3 to glutaraldehyde, 1 to both, and 2 to ethanolamines.
Moderate evidence.
Caveats
The causal agent was inferred from product ingredients, not isolated; 9 workers challenged with QAC-containing products did not react (derived from Table 1). Authors name lack of quantitative exposure assessment as the main limitation.
Health effects / Review of other studies
A 2016 review of professional clothing-cleaning methods reports that perchloroethylene (perc), the most widely used dry-cleaning solvent, is classed by the International Agency for Research on Cancer as probably carcinogenic to humans (group 2A), with kidney cancer, liver cancer, and non-Hodgkin lymphoma among the cancers linked to it in workers or residents.
Moderate evidence.
Caveats
Secondary review funded by Australian Wool Innovation (wool industry body); 'systematic' is a self-label with no study counts or appraisal; relies on agency, trade and manufacturer sources. The review restates other studies' findings; it contains no new exposure or outcome data, and the IARC class is a hazard rating, not a risk estimate for wearing dry-cleaned clothes.
Source: Troynikov 2016, Journal of Environmental Management Industry-funded Link to this fact
Health effects / Other evidence
The panel says frequent use of bleach, ammonia and degreasing sprays has been consistently associated with asthma in cleaning workers, but the specific chemicals and mechanisms are unclear because cleaning products contain many ingredients, some irritants and some sensitizers.
Moderate evidence: Occupational cleaners, not consumers; consensus statement; cited studies used qualitative exposure assessment.
Health effects / Review of other studies
Published cases of lasting asthma after a single accidental inhalation (RADS) have most often involved chlorine or chlorine-releasing chemicals, including cleaning of bathrooms, kitchens and toilets (44 cases in one series) and accidentally mixed chemicals at work.
Moderate evidence: Review of case reports, series and conference abstracts; mostly workplace accidents; frequency of report is not potency or incidence; no exposure levels.
Source: Walters 2020, Occupational Medicine Link to this fact
Health effects / Other evidence
In a random survey of 1,582 adults in the Atlanta, Georgia metro area (1999-2000), 12.6% said they were allergic or unusually sensitive to everyday chemicals like cleaning products, paints, perfumes, detergents and insect spray, and 3.1% said a doctor had diagnosed multiple chemical sensitivity or environmental illness.
Moderate evidence: Self-report only, one metro area; sampling frame, interview mode and response rate are not reported in this brief; no clinical verification.
Source: Caress & Steinemann 2004 (AJPH), American Journal of Public Health Link to this fact
Hidden ingredients / Measured in people or real products
When researchers tested 25 best-selling US laundry, cleaning, personal-care, and air-freshener products, they found 133 different chemicals released into the air, but only 1 of them was listed on any product label.
Moderate evidence: Single headspace sample per product; VOC counts depend on detection threshold.
Source: Steinemann 2011, Environmental Impact Assessment Review Link to this fact
Hidden ingredients / Measured in people or real products
In 2018, testing commissioned by Breast Cancer Prevention Partners of 25 personal care and 7 cleaning products found chemicals flagged for cancer, hormone disruption, respiratory, or developmental hazards that were not on the label; 99 of the 124 were on the fragrance industry's own ingredient list.
Moderate evidence: Not peer reviewed; labs, detection limits, and concentrations not reported; hazard = database flag; IFRA list includes multifunctional solvents/preservatives.
Source: BCPP 2018 Link to this fact
Hidden ingredients / Measured in people or real products
Di(2-ethylhexyl) phthalate (DEHP), a plasticizer used to make nail polish more flexible and durable, was the most abundant of six phthalates measured on silicone wristbands in all 10 nail salons tested (median 391.80 ng/g-wristband), with diethyl phthalate (DEP) second highest (median 154.4 ng/g-wristband) — but the paper never discusses what produces its measured DEP, unlike its explicit attribution of DEHP to nail polish and d-limonene to cleaning/fragrance products.
Moderate evidence.
Caveats
Small sample (n=10 for phthalates); wristband measurement is a sorbed dose, not a direct air concentration; the paper's own figures and Discussion text mislabel this unit as ppb instead of the Methods/footnote's ng/g-wristband, an internal inconsistency in the published article.
Source: Han et al. 2022 Link to this fact
Hidden ingredients / Other evidence
The workers were challenged with commercial cleaning products that contained mixtures of irritants and possible sensitizers, so the authors could not formally identify which ingredient caused each reaction.
Moderate evidence: Authors' own limitation statement; they infer QACs from known asthma-hazard predictions (asthma hazard index 0.81-0.95), which is a model score, not a test of the product.
Hidden ingredients / Measured in people or real products
The chamber test detected 530 distinct VOCs from 30 cleaning products and air fresheners, and only 17% of them appear in the cleaning industry association's ingredient database (American Cleaning Institute); 23 of 30 products were not fragrance-free and 7 of those listed just 'fragrance'.
Moderate evidence.
Caveats
EWG-authored (advocacy nonprofit that ranks cleaners and licenses EWG VERIFIED to cleaner makers); Skyline Foundation grant; unblinded; Detection of a chemical in chamber air does not show it was an intentional ingredient; some are impurities, by-products or sampling artifacts; 71% of VOCs were found in a single product.
Hidden ingredients / Other evidence
EWG Verified cleaning products must disclose every intentionally added fragrance ingredient publicly down to 0.01 percent, which no US federal rule requires of household cleaners.
Moderate evidence.
Caveats
Applies only to products that opt in and are licensed; the document states requirements, not compliance rates; amounts of ingredients are not disclosed. The comparison with US law relies on our other pages, not on this document.
Source: EWG Verified criteria for cleaning products (10.24), Environmental Working Group, 2024 Link to this fact
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
Information, not medical advice. See also: myths we won’t tell you.