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
In 34 California childcare centers, the chemicals at the highest levels in the air children breathed came from cleaning and personal-care products: a silicone ingredient called D5 (median 51 µg/m³) and the citrus-scent chemical limonene (median 33 µg/m³).
Strong evidence: Single-day samples; upper values capped by calibration (underestimates).
Children and pregnancy / Measured in people or real products
Synthetic musk fragrance chemicals were found in the breast milk of every one of 39 Massachusetts mothers tested in 2004; the most common, galaxolide (HHCB), was in 97% of them.
Strong evidence: One US state, 2004 samples, n=39; no product-use data; no health outcome.
Source: Reiner 2007, Environmental Science & Technology Link to this fact
Children and pregnancy / Measured in people or real products
Musk scent chemicals used in perfumes, deodorants, and detergents turn up in mothers' milk fat; a breastfed baby takes in an estimated ~2 micrograms of galaxolide a day.
Strong evidence.
Caveats
Intake is a model estimate from means of detects; the printed intakes do not reproduce from the stated method. Independently corroborated: Lignell 2008 (N=101, Swedish mothers, single lab) estimated median infant HHCB intake at 1650 ng/day (range 50-6950) using the same milk-intake modeling approach, closely matching this paper's printed 1830 ng/day figure in an unrelated country and cohort.
Source: Reiner 2007, Environmental Science & Technology Link to this fact
Children and pregnancy / Review of other studies
Children exposed to household chemical/cleaning products before birth or in their first year wheeze more often, now replicated in four independent prospective birth cohorts. The founding ALSPAC cohort (UK, n=7,019, Sherriff et al. 2005) found that an 11-product, frequency-weighted prenatal household chemical (TCB) score was significantly associated with persistent wheeze through 3.5 years (adjusted OR 1.06 per unit increase; top-vs-bottom-decile adjusted OR 2.3), but not with transient early or late-onset wheeze; this is the same ALSPAC cohort and composite-score methodology that both Casas 2013 and Mikeš 2019 name as their model. In the Canadian CHILD cohort (n=2,022), frequent use in early infancy was linked to higher odds of recurrent wheeze (adjusted OR 1.35) and asthma diagnosis (adjusted OR 1.37) by age 3, but not isolated skin-prick allergy (adjusted OR 1.14, ns), though wheeze combined with allergy was itself raised (adjusted OR 1.49). In the Czech ELSPAC-CZ cohort (n=3,411), each 1-SD increase in an 18-product household chemical exposure score at 6 months raised the odds of intermediate-onset transient, intermediate-onset persistent, and early-onset persistent wheeze phenotypes through age 5 (adjusted OR 1.23-1.36), and those persistent phenotypes carried 5-8x higher odds of doctor-diagnosed asthma at age 7 (pediatrician records, not self-report). In the pooled Spanish INMA cohorts (n=2,292), prenatal (third-trimester) use of cleaning sprays raised the odds of both wheezing (OR 1.37) and lower respiratory tract infection (OR 1.29) in the first year of life, with solvents raising wheezing odds (OR 1.30) and air fresheners raising LRTI odds (OR 1.29); bleach, ammonia, and non-spray cleaners showed no association.
Strong evidence.
Caveats
All four cohorts are observational and use self-reported product-use frequency, not measured indoor air chemistry. The ALSPAC/Sherriff 2005 and ELSPAC-CZ signals are specific to persistent-type wheeze phenotypes, not wheeze in general; ALSPAC found no association with transient early or late-onset wheeze. The 'not atopy' finding remains single-cohort (CHILD only); ELSPAC-CZ's atopic-rash variable is a covariate, not an outcome, and Casas 2013 measured neither atopy nor a physician asthma diagnosis, only maternal-reported LRTI and any-wheezing through 12-18 months, so it neither confirms nor refutes the atopy finding; ALSPAC/Sherriff 2005 did not assess atopy or asthma at all. Casas 2013 is the only cohort among the three post-2010 cohorts with genuinely prenatal (rather than early-postnatal) exposure measurement, but ALSPAC/Sherriff 2005 is also prenatal and its composite score behaved like CHILD's and ELSPAC-CZ's (significant), not like Casas's (null) — evidence against prenatal timing per se explaining the Casas null. Casas 2013's own summed cleaning-product-count score was NOT a significant predictor, unlike ALSPAC's, CHILD's, and ELSPAC-CZ's frequency-weighted composite scores — an open methodological tension (register entry C262) that means 'more products used' is not yet a uniformly replicated exposure metric across all cohorts, even though several specific products (sprays consistently, plus solvents and air fresheners) are.
Source: Salonen 2024, Environment International Link to this fact
Fragrance is everywhere / Measured in people or real products
In the US, everyday chemical products (paints, inks, glues, cleaners, personal care products, and pesticides) now release about twice as much air-polluting vapor as cars and trucks: 7.6 vs 3.5 million metric tons in 2012.
Strong evidence: All chemical products, not fragrance specifically; coatings/inks/adhesives are 58%.
Fragrance is everywhere / Measured in people or real products
Even in Perth, a city with very clean outdoor air, limonene and pinene (scent chemicals typical of citrus- and pine-scented cleaners and air fresheners) were found in 80-100% of homes when a sensitive test was used.
Strong evidence: Low concentrations (median ~1.5-2.4 µg/m³); sources not measured; 64 weekday-daytime visits.
Source: Maisey 2013, Atmospheric Environment Link to this fact
Fragrance is everywhere / Measured in people or real products
In EPA's large 1980s studies of US homes, limonene, the chemical behind lemon scents, was the airborne chemical with the highest average concentration in people's homes.
Strong evidence: 1980-87 TEAM data; no health risk estimated for limonene.
Source: Wallace 1991, Environmental Health Perspectives Link to this fact
Fragrance is everywhere / Measured in people or real products
Scientists can identify which everyday products are polluting a city's outdoor air just by measuring a handful of specific chemical fingerprints: a silicone compound (D5-siloxane) for personal-care products and citrus/pine-scent chemicals (monoterpenes, mostly limonene) for fragranced products, confirmed by mobile-lab measurements across New York City, Pittsburgh, Chicago, and Denver.
Strong evidence: Outdoor air only; four US cities, no LA data; tracer status is based on population-density correlation and inventory apportionment, not a direct source test.
Source: Gkatzelis 2021, Environmental Science & Technology Link to this fact
Fragrance is everywhere / Measured in people or real products
Two completely different ways of estimating pollution from chemical products, one based on direct air measurements and one based on how much of each product gets sold and used, agreed with each other to within about a quarter.
Strong evidence: Agreement within 25% for the bulk comparison and within 30% for more than half of individual compounds compared, in Boulder and NYC only.
Source: Gkatzelis 2021b, Environmental Science & Technology Link to this fact
Fragrance is everywhere / Measured in people or real products
Musk fragrance chemicals were found in the breast milk of all 101 Swedish first-time mothers tested; the musk chemical galaxolide (HHCB) was detected in every single sample across a seven-year span (1996-2003).
Strong evidence: One Swedish county, single lab/method, N=101; no infant health outcome measured.
Source: Lignell 2008, Environmental Science & Technology Link to this fact
Fragrance is everywhere / Review of other studies
Human skin releases more than 400 different volatile compounds in total, but any single sampling study of airborne skin volatiles only ever captures 20 to 90 of them, so the reported 'chemical signature' of human skin varies hugely from paper to paper depending on the method used, not necessarily on real biological differences.
Strong evidence.
Caveats
Synthesis across 24 sampling studies and a 31-reference compilation of detected compounds (this review's own Tables 1 and 2), not a single new measurement; no head-to-head method comparison exists in the underlying literature.
Source: Dormont et al. 2013, Journal of Chemical Ecology Link to this fact
Fragrance is everywhere / Government agency
There are no longer any pristine, unpolluted places on Earth: endocrine-disrupting chemicals such as PFOS have been measured in marine-mammal tissue from the Arctic to remote Southern Hemisphere waters, far from any point source, carried by long-range air and ocean transport and biomagnified through food webs.
Strong evidence: Illustrated with wildlife biomonitoring data (marine mammals), not a direct measurement of fragrance or consumer-product chemicals specifically.
Source: WHO/UNEP 2012 Link to this fact
Green, natural and unscented / Measured in people or real products
'Natural' oils get no special protection from air: in lab tests, lavender oil's main scent chemicals oxidized just as fast as a synthetic copy made only of those chemicals, and formed the same allergenic hydroperoxides.
Strong evidence: Lab chemistry, neat oil in open flasks over 10-45 weeks; one oil type (lavender), two batches.
Source: Hagvall 2008, Contact Dermatitis Industry-funded Link to this fact
Green, natural and unscented / Other evidence
Seal of Acceptance products must also exclude a named 34-ingredient Ecz-clusion List (including cinnamic alcohol, cinnamic aldehyde, coumarin, eugenol, farnesol, geraniol, hydroxycitronellal, isoeugenol, oak moss absolute, and several citrus extracts), chemical UV absorbers other than titanium/zinc/iron physical sunscreens, and formaldehyde releasers, in any amount.
Strong evidence: Ingredient-list exclusion, verified by NEA's own review, not independent chemical assay of finished products.
Source: NEA 2026 Link to this fact
Green, natural and unscented / Other evidence
OEKO-TEX Standard 100's limit table has no limit and no list for fragrance chemicals or fragrance allergens; the only fragrance-related rule is an odor test that requires 'no odor from mold, high boiling fraction of petrol, fish, aromatic hydrocarbons, or perfume'.
Strong evidence: Edition 02.2025 table only; the 2026 change notice mentions no fragrance row but the full 2026 table was not captured; odor test is a sensory judgment with no stated scale.
Source: OEKO-TEX Service GmbH, Standard 100 limit values Annexes 4-5, Ed. 02.2025 Industry-funded Link to this fact
Health effects / Measured in people or real products
In the largest controlled test of its kind, 130 healthy young women breathing an indoor chemical mixture with and without ozone for 140 minutes showed no significant change in symptoms, lung function, attention, or the stress hormone cortisol.
Strong evidence: Healthy women only; asthma and chemical sensitivity excluded; one 140-min exposure at 1.8 air changes/h; eye-blink rate not measured.
Source: Fiedler 2005, Environmental Health Perspectives Link to this fact
Health effects / Measured in people or real products
Every controlled chamber study in a 103-study review of asthma and airborne chemicals excluded people with moderate or severe asthma by design; the one study that directly compared severity groups found the more severe group had the largest airway response, though not statistically significant in that small sample.
Strong evidence: Direction, not magnitude: the comparison (Linn et al. 1987) was underpowered and did not reach significance.
Source: Johansson 2016, Critical Reviews in Toxicology Link to this fact
Health effects / Measured in people or real products
Most patients with scent- and chemical-triggered breathing symptoms in this study (8 of 12) were already taking asthma inhalers or steroid inhalers and said the drugs gave little or no relief, matching an independent Canadian clinic's finding that a similar scent-triggered condition does not respond to asthma medication.
Strong evidence.
Caveats
Both this and the corroborating study (Hoy 2010) are single-clinic case series (n=12 and n=30); 'little relief' is patient-reported, not measured by a controlled inhaler-response trial.
Health effects / Other evidence
The EU's safety margin of 192 for conditioner quats (cetrimonium, steartrimonium, behentrimonium chloride) rests on a skin-absorption value borrowed from a different, shorter-chain chemical (laurtrimonium bromide, rat, 1979) and a 12-month rat study of cetrimonium bromide; the committee itself called the absorption value a compromise.
Strong evidence: The committee also says rat skin is usually more permeable than human skin, so 3.15% may overestimate; the MoS is a worst-case figure against a benchmark of 100.
Source: SCCS 2009 trimoniums, SCCS opinion (PDF) Link to this fact
Hidden ingredients / Review of other studies
US law does not require the individual chemicals in a fragrance to be listed, so a shopper cannot tell from the label whether a scented product contains diethyl phthalate.
Strong evidence: Regulatory background statement, as of 2013.
Source: Parlett 2013, Journal of Exposure Science and Environmental Epidemiology Link to this fact
Hidden ingredients / Review of other studies
None of the products used by the four affected children was ever chemically analyzed; the researchers could only assume that a product labeled as containing lavender oil actually met the international composition standard.
Strong evidence.
Caveats
Stated by the authors as a limitation; an industry letter later claimed one named cologne contained diethyl phthalate and no lavender oil, which has also never been independently verified.
Source: Ramsey 2019, The Journal of Clinical Endocrinology & Metabolism Link to this fact
Hidden ingredients / Other evidence
Under EU flavoring law a consumer ingredient list may say simply 'flavorings' (or a more specific name or description) without naming the flavor's chemical components; business-to-business labels must list the categories of flavorings present but not each flavoring substance.
Strong evidence: Allergen rules sit in other law (see the Regulation 1169/2011 page); Art. 15(1)(g) does require buyers to be told the maximum quantity of components subject to limits.
Source: EU Regulation 1334/2008, Art. 29 and Art. 15 Link to this fact
Indoor air / Review of other studies
A chemical released indoors is roughly 1,000 times more likely to be breathed in than the same amount released outdoors (exact when comparing the low end of each range; only ~100x at the high end, since the ranges overlap at 10⁻³), so cleaning products and air fresheners (about 1% of California's smog-forming emissions) may deliver an inhaled dose on the same scale as all outdoor sources combined.
Strong evidence.
Caveats
Modeled population intake fractions (not measurements), population-average estimate. Traced to the primary source, Lai, Thatcher & Nazaroff 2000 (JAWMA 50:1688-1699), which derives outdoor PITF 10⁻⁶-10⁻³ vs indoor/in-vehicle PITF 10⁻³-10⁻¹ from Gaussian-plume and mass-balance modeling (Nazaroff co-author of both papers, so this is not independent replication). The ranges overlap at 10⁻³, so '1000x' is a floor-to-floor comparison, not a fixed multiplier under all conditions.
Source: Nazaroff & Weschler 2004, Atmospheric Environment Link to this fact
Indoor air / Review of other studies
Scent chemicals such as limonene and pine oil react with ozone indoors to make new pollutants, including formaldehyde and fine particles, that keep forming for hours after cleaning ends.
Strong evidence: Size of the effect depends on dose and indoor ozone; confirmed by later chamber and field studies.
Source: Nazaroff & Weschler 2004, Atmospheric Environment Link to this fact
Indoor air / Measured in people or real products
Questionnaires about habits and routines correctly sorted only 20% of people by their measured exposure to cleaning and fragrance chemicals, vs 61% for traffic fumes; exposure depends on individual behavior and product choice.
Strong evidence.
Caveats
'Product choice' is the authors' explanation, not directly tested in this paper; independently corroborated by a larger, more direct 2021 UK study (Heeley-Hill 2021, 60 homes, daily diary-logged — not recalled — product-use frequency vs measured concentrations) that found cumulative product-use frequency has essentially no predictive power for measured indoor VOC concentrations (R²<0.001 for total VOC; no individual VOC significant).
Source: Edwards 2006, Atmospheric Environment Industry-funded Link to this fact
Indoor air / Review of other studies
Scent chemicals released by perfumes and scented products can react with ozone in indoor air to form new pollutants, including formaldehyde and fine particles.
Strong evidence.
Caveats
Formation is well established (Fiedler 2005: 40 ppb O3 + a limonene/alpha-pinene-containing VOC mix -> HCHO 13 -> 40 µg/m³, UFP 2,500 -> 46,000 cm-3; Singer 2006; Rossignol 2013; Destaillats 2006 gives the underlying per-ozone yield). Amounts depend on dose and ozone; the harm at real indoor levels is not shown. A far more rigorous, independent toxicologist review (Wolkoff & Nielsen 2017) reaches the same qualitative chemistry conclusion via its own literature synthesis and adds a quantitative caution: in the two largest human tests to date (Fiedler 2005, n=130; Fadeyi 2015, n=71), the resulting reaction mixture caused no significant airway/eye effects, and its own threshold estimate is that >200 µg/m³ ozone at high limonene would be needed before sensory effects are expected. Cite primaries for numbers.
Source: Alblooshi 2025, Frontiers in Toxicology Link to this fact
Indoor air / Measured in people or real products
Across decades of US monitoring where people carried personal air samplers, the air they breathed held more of almost every hazardous chemical than outdoor air did: exposure happens indoors, not at the outdoor monitoring station.
Strong evidence: Older studies include smokers' homes; compound-specific.
Source: Weisel 2002, Environmental Health Perspectives Link to this fact
Indoor air / Measured in people or real products
In week-long air measurements across 11 European cities, the scent chemicals limonene and alpha-pinene were the compounds most concentrated in homes compared with workplaces (about 4x), attributed to perfumes, cleaning and fragranced products.
Strong evidence: Source attribution by the authors, not measured per product.
Source: Geiss 2011, Atmospheric Environment Link to this fact
Indoor air / Measured in people or real products
Limonene was 13x higher indoors than outdoors in European offices and classrooms, one of the two highest indoor/outdoor ratios of 23 chemicals measured.
Strong evidence: Ratio of medians.
Source: Geiss 2011, Atmospheric Environment Link to this fact
Indoor air / Measured in people or real products
Scent-type chemicals typical of fragranced and cleaning products (limonene, pinene, carene) were the signature of home air: close to zero outdoors but tens to hundreds of times higher inside homes.
Strong evidence.
Caveats
Small original study (n=7); the indoor-source signature (not the specific product-category attribution) is now independently replicated by a much larger 2021 UK study with real paired outdoor sampling (Heeley-Hill 2021, 60 homes: limonene indoor:outdoor ~19x, alpha-pinene ~10x), though that larger study also found cumulative product-use frequency does not predict concentration (only insecticide/plug-in-air-freshener use showed weak covariance with limonene) — so the indoor-source signature is strong, the specific 'cleaning products' attribution stays inferential. Givaudan-funded (COI); analysis independent.
Source: Gokhale 2008, Science of the Total Environment Link to this fact
Indoor air / Lab study (cells or chemistry)
What you breathe after using a scented cleaner is not only what was in the bottle: the scent chemicals keep reacting in the air to make new compounds.
Strong evidence: Well-established chemistry; magnitude indoors depends on ozone levels.
Indoor air / Measured in people or real products
When scent chemicals from a pine-oil cleaner, an orange-oil degreaser, and a plug-in air freshener met ozone in a lab chamber, about one formaldehyde molecule formed for every 3-5 ozone molecules they used up (yields of 20-30% in most tests).
Strong evidence.
Caveats
Same three products as Singer 2006, same research group/CARB contract, not independent replication; the highest single value (90%) occurred at air-freshener vapor loads 30-45x a real room's plug-in levels.
Source: Destaillats 2006, Environmental Science & Technology Link to this fact
The industry / Lab study (cells or chemistry)
The lab tests that replaced animal testing for setting cosmetic and fragrance allergy safety limits explain only about 62% of how strongly a chemical causes allergy.
Strong evidence.
Caveats
Regression R2 against mouse LLNA, not human outcomes; industry-authored. Natsch 2023 (same author) retrains against human-anchored data: the 62% figure survives on a blended human+LLNA composite (63.4%, n=139), but against strictly human data (n=62) accuracy drops to 32-45%, and even the LLNA itself only reaches 43% predicting human potency — so '62%' should not be read as human-relevant accuracy. Api, Basketter & Lalko 2014 (RIFM's own earlier LLNA-vs-human validation, 57 fragrance chemicals) independently corroborates, by a different metric (categorical concordance, not R2) and seven years earlier, that the LLNA itself is an imperfect human proxy: 76% agreement within half an order of magnitude, but up to ~790-fold mispredicted for salicylates and ~26-42-fold for trans-2-hexenal/methyl-2-nonanoate. Roberts & Api 2018 (same fragrance dataset, direct LLNA-vs-human regression) reports a much higher R2=0.784, but only for a 35-chemical subset that already excludes those 14 known outliers a priori — demonstrating that domain-restricted R2 figures like this one can substantially overstate accuracy on unselected chemistry, a caution that applies to curated NAM training/case-study sets generally, not only to this specific figure.
Source: Natsch & Gerberick 2022, ALTEX Industry-funded Link to this fact
The industry / Review of other studies
Much of the evidence behind the fragrance industry's 'safe as used' verdict on salicylates is unpublished: about 65 of the cited studies are internal RIFM reports, several submitted by fragrance companies, and no modern cancer bioassay exists for any of the 17 chemicals.
Strong evidence: Counted from the paper's reference list; 'no modern bioassay' means untested, not shown to be carcinogenic.
Source: RIFM Expert Panel / Belsito 2007, Food and Chemical Toxicology Industry-funded Link to this fact
The industry / Animal study
The two molecules that give lavender oil its scent, linalool and linalyl acetate, were put through the full regulatory endocrine test battery (OECD guideline cell assays plus rat uterotrophic, Hershberger, and one-generation reproductive studies) and came back negative on estrogen and androgen endpoints, in a study written, run, and entirely funded by BASF, the company that manufactures both chemicals, with all five authors BASF employees.
Strong evidence.
Caveats
Guideline designs with working positive controls, so the negative is real; the conflict of interest is disclosed in the paper and should be stated whenever the result is cited. Scope: two constituents, not lavender or tea tree oil.
Source: Hareng 2024, Archives of Toxicology Industry-funded Link to this fact
The industry / Other evidence
A 2014 peer-reviewed critique disputing the WHO-UNEP 2012 endocrine-disruptor report's evidence standards was funded by six chemical- and pesticide-industry trade associations (American Chemistry Council, CropLife America, CropLife Canada, CropLife International, Cefic, and the European Crop Protection Association), which were given the opportunity to review and comment on the draft before publication; most of the authors are employees of industry-consulting firms (Exponent, Gradient) or paid consultants/testifying experts for the chemical industry in litigation over pesticides, PCBs, and dioxins.
Strong evidence.
Caveats
This describes the funding and authorship of the critique itself, not the truth or falsity of any individual claim it makes — several of its specific factual points are independently checkable against the primary sources it cites.
Source: Lamb et al. 2014, Regulatory Toxicology and Pharmacology Industry-funded Link to this fact
The industry / Government agency
As of 2021, the EU's cosmetics regulator states directly that it is not yet possible to use the fragrance industry's QRA2 methodology to set a concentration below which a fragrance chemical is unlikely to cause allergy in new users.
Strong evidence: A regulatory verdict on methodology validity, not a finding that current fragrance concentration limits are unsafe; QRA2 remains in industry use for setting IFRA limits regardless.
The industry / Government agency
The EU's cosmetics regulator treats chemicals suspected of disrupting hormones the same way it treats other health-concern chemicals: through a risk assessment weighing exposure level, not an automatic hazard-based ban.
Strong evidence.
Caveats
This is the SCCS's stated position for cosmetics specifically; other EU sectors (pesticides, biocides) use a stricter hazard-based approach for the same class of chemicals, a policy split the regulator itself has acknowledged elsewhere.
The industry / Measured in people or real products
This 24-formulation detergent skin-irritation comparison was sponsored and funded by the Soap and Detergent Association trade group, with test formulations supplied by a consortium including Procter & Gamble, Colgate-Palmolive, Shell Chemical, Unilever, Reckitt Benckiser, S.C. Johnson, Clorox, and Access Business Group (Amway); the study's statistical analysis was performed by a named Procter & Gamble scientist.
Strong evidence.
Caveats
Funding and authorship are directly stated in the paper's acknowledgments and affiliations; this is a description of the study's sponsorship, not an independent replication of its findings.
Source: Robinson et al. 2005, Food and Chemical Toxicology Industry-funded Link to this fact
Laws and loopholes / Review of other studies
As of 2008, no US federal law required companies to list all the chemicals in a consumer product or in its fragrance; air fresheners and laundry products did not even have to say they contained fragrance.
Strong evidence.
Caveats
US law as of 2008; MoCRA (2022) later required FDA-designated fragrance-allergen labeling for cosmetics only (rule pending at enactment); household products still uncovered for cosmetics.
Source: Steinemann 2009, Environmental Impact Assessment Review Link to this fact
Laws and loopholes / Review of other studies
When US EPA scientists built a database of chemicals in 8,921 consumer products from their safety data sheets, they could not record fragrance ingredients at all: more than 3,060 fragrance materials can legally be listed as 'trade secret' with no name, so those entries had to be thrown out.
Strong evidence: Document analysis of one US retailer's MSDSs (2012).
Source: Goldsmith 2014, Food and Chemical Toxicology Link to this fact
Laws and loopholes / Review of other studies
Product safety data sheets are written for workers, not shoppers, and only have to list hazardous ingredients present above 1% (0.1% for cancer-causing ones), a level most individual fragrance chemicals fall below.
Strong evidence: 'Most fragrance chemicals below 1%' is general formulation knowledge, not measured in this paper.
Source: Goldsmith 2014, Food and Chemical Toxicology Link to this fact
Laws and loopholes / Review of other studies
Since the 2022 MoCRA law, most cosmetic makers must list their products with the FDA; in its December 2025 report the FDA found PFAS ("forever chemicals") intentionally added to about 0.4% of listed US cosmetics (1,744 of 430,134), mostly eye and face makeup, and had too little data to judge the safety of 19 of the 25 most-used PFAS.
Strong evidence.
Caveats
Manufacturer listings, not product testing; small businesses and drug-cosmetics do not list; corrected 2026-09-26 from 0.03%/no fragrances (EU KEMI figures). Independently corroborated 2026-09-27: Balan et al. 2024 (10.1021/acs.est.3c06539, California DTSC) estimated PFAS-containing-product prevalence from a different, non-federal dataset (Mintel Global New Product Database + EWG Skin Deep, ~65,000+ formulations) and found prevalence under 3% in every one of 16 product subcategories studied (range 0.00-2.68%), consistent with FDA's 0.41% aggregate figure. Both remain database/listing-based estimates, not chemical measurements, and the two studies measure slightly different things (an economy-wide aggregate vs. per-subcategory prevalence in 16 categories), so this is convergence of two independent large datasets rather than a replication of the identical statistic.
Source: FDA 2025, FDA report published under MoCRA §3506(b) (FDA website) Link to this fact
Laws and loopholes / Review of other studies
In the US, "fragrance" can be listed as a single word because the mixture is protected as a trade secret, so the individual chemicals are rarely named on the label.
Strong evidence.
Source: Pinkas 2017, Environmental Research Link to this fact
Laws and loopholes / Review of other studies
In the EU, chemical mixtures containing a skin sensitizer must carry the warning 'May produce an allergic reaction' (EUH208), but cosmetics are exempt from that warning and from CLP hazard symbols.
Strong evidence: Legal analysis as of 2016 (CLP Art. 1(5), Annex II 2.8); cosmetics do have to name listed allergens in the ingredient list.
Source: Klaschka 2016, Environmental Sciences Europe Link to this fact
Laws and loopholes / Measured in people or real products
No EU or Belgian law requires fragrance ingredients in topical medicines to be named on the label, or restricts which fragrance chemicals they may contain, unlike cosmetics, where the EU has required disclosure of major fragrance allergens since 2005.
Strong evidence: Regulatory statement as described in a 2009 paper; check current EU medicines regulation for any changes since.
Laws and loopholes / Government agency
A systematic comparison of occupational exposure limits from 18 countries and agencies found that only 25 of 1,341 chemicals studied have a limit set by every agency, and more than a third of the chemicals are regulated by only one of the 18.
Strong evidence: Workplace limits only, not consumer or indoor-air limits. A single (if large and systematic) comparative study; the paper does not analyze why the differences exist.
Source: Schenk et al. 2008, Regulatory Toxicology and Pharmacology Industry-funded Link to this fact
Laws and loopholes / Other evidence
Since 2005 the EU has required cosmetic and detergent products to name 26 specific fragrance chemicals on the label if present above 10 ppm in leave-on products or 100 ppm in rinse-off products; every other fragrance ingredient can still be hidden under the single word "parfum" or "fragrance".
Strong evidence.
Caveats
Settled EU statutory requirement as of the review's writing (2020); does not cover the many countries without an equivalent rule, and the EU later expanded the list to 56 substances (2023/1545, tracked elsewhere in our evidence base).
Source: de Groot 2020, Dermatitis 31(1):13-35, Dermatitis® Link to this fact
Laws and loopholes / Government agency
The EU's 2018 endocrine disruptor policy Communication states that endocrine disruptors are regulated completely differently depending on the law: under pesticide and biocide rules, once a substance is proven to be an endocrine disruptor it can in principle no longer be authorized at all, with very limited exceptions, but under the EU's main chemicals law (REACH) and under cosmetics, toys, and food-contact-material rules, an identified endocrine disruptor is instead assessed case by case and can still be allowed at a managed exposure level.
Strong evidence.
Caveats
The Commission itself calls this inconsistency an open question, not a settled policy failure, and says a 'Fitness Check' (not yet published as of this 2018 document) will examine whether it needs to change.
Source: EU Commission 2018 Link to this fact
Laws and loopholes / Government agency
As of November 2018, EU rules for cosmetics, toys, and food-contact materials contained no provisions specific to endocrine disruptors at all; those chemicals were covered only by each law's general safety requirements.
Strong evidence.
Caveats
Individual endocrine-linked ingredients (certain parabens, one UV filter, bisphenol A) are still restricted or banned in cosmetics, toys, and food-contact materials product by product, not through an endocrine-disruptor-specific rule.
Source: EU Commission 2018 Link to this fact
Laws and loopholes / Government agency
In 1992, the U.S. Department of Justice held that whether multiple chemical sensitivity (MCS) or "environmental illness" counts as a disability under Section 504 of the Rehabilitation Act (and, by the same analysis, the ADA) is decided case by case, not by diagnosis alone: the test is whether the person's impairment substantially limits a major life activity, given their particular circumstances.
Strong evidence.
Caveats
This is DOJ's own legal position as the federal Section 504 coordinating agency, not a scientific finding about MCS; it takes no position on causation or prevalence, only on the legal disability test.
Source: DOJ 1992 Link to this fact
Laws and loopholes / Government agency
The new EU fragrance-allergen entries are implemented as 45 new Annex III reference numbers (327-371), several of which bundle multiple named plant-oil species or chemical isomers under a single entry number — for example one entry covers 7 named rose species and another covers 4 named lavender/narcissus species.
Strong evidence: Counted directly from the regulation's Annex text, cross-checked against page-image crops of two entries.
Source: Regulation (EU) 2023/1545 Link to this fact
Laws and loopholes / Government agency
The EU's 2023 fragrance-allergen expansion includes many whole essential oils and plant extracts by species, not just synthetic single chemicals — including lavender, rose, bergamot, ylang ylang, clove, sandalwood, patchouli, cedarwood, geranium, and peppermint oils.
Strong evidence: Each named oil/extract is its own Annex III reference number with its own CAS number(s); 'natural' or 'essential oil' products are not exempt from these labeling obligations.
Source: Regulation (EU) 2023/1545 Link to this fact
Laws and loopholes / Other evidence
Under a 1958 law exception, a food company can decide a chemical is 'generally recognized as safe' (GRAS) without telling FDA; since 1997 FDA's voluntary notice program reviews the company's own conclusion in a private exchange with no formal public comment, and virtually all new direct food chemicals now go this route instead of the formal food-additive petition.
Strong evidence.
Caveats
Describes the program's structure as characterized by the paper's Pew authors (an advocacy-side view); structure is documented in FDA's own rules and notices. Still true of the current final rule (2016); FDA proposed in August 2026 (91 FR 51834, not final) to make notice mandatory.
Source: Maffini 2013, Comprehensive Reviews in Food Science and Food Safety Link to this fact
Laws and loopholes / Review of other studies
Under US law a company may decide on its own that a food chemical is 'generally recognized as safe' and put it in food with no legal duty to tell FDA; the Pew authors say the decision can rest on the company's own employees or an expert panel it selects.
Strong evidence: Legal description by Pew Health Group authors (advocates of mandatory notice); FDA's 2016 rule confirms notice stays voluntary. Dated 2011.
Source: Neltner et al. 2011, Compr Rev Food Sci Food Saf, Comprehensive Reviews in Food Science and Food Safety Link to this fact
Laws and loopholes / Other evidence
The specific OSHA rules OSHA lists as relevant to indoor air are ventilation (29 CFR 1910.94), air contaminant limits (1910.1000), formaldehyde (1910.1048) and laboratory chemicals (1910.1450); none is a fragrance or general IAQ rule.
Strong evidence: List is OSHA's 2011 'some of the applicable' standards, not exhaustive.
Source: OSHA 3430-04, 2011 Link to this fact
Skin allergy / Measured in people or real products
In 658 Danish/Swedish patients with hand eczema, 67 (10.2%) reacted to fragrance chemicals commonly found in household products, and the standard fragrance-mix patch test alone would have missed more than half of these reactions.
Strong evidence.
Caveats
Clinic-referred hand-eczema population, not the general public. Confirmed directly against the full primary (Heydorn et al. 2003, Contact Dermatitis 48:317-323), not just its PubMed abstract or Kumar 2020's secondary table.
Source: Kumar 2020 (Heydorn 2003), Journal of Cosmetic Dermatology Link to this fact
Skin allergy / Measured in people or real products
The fragrance chemicals most often found in household products were mostly not in the standard fragrance-allergy patch test used at the time: 6 of its 8 chemicals were in 12% of products or fewer.
Strong evidence.
Caveats
Frequency in products is not the same as clinical sensitization rate; FM II and hydroperoxide testing later added. Clinically confirmed in Heydorn et al. 2003 (n=658 hand-eczema patients, 3 centers): only 3 of the 14 chemicals selected from this paper's household-product survey were FM I constituents, and FM I caught only 45.5% of the fragrance-allergic patients (5.6% of all patients tested missed). The exposure-frequency leader, limonene (78% of products), caused only 0.8-0.9% oxidized-limonene reactivity clinically — product frequency of a chemical still does not predict its clinical allergy rate.
Source: Rastogi 2001, Contact Dermatitis Industry-funded Link to this fact
Skin allergy / Measured in people or real products
Common scent chemicals such as linalool hardly cause allergy when fresh, but once exposed to air they form new chemicals that do: in 1,511 dermatitis patients at six European clinics, 1.3% were allergic to air-oxidized linalool (later studies with a stronger test found about 7%).
Strong evidence.
Caveats
Dermatitis patients, not general population; 2005 test concentration (2.0% pet.) was later shown too low. Clinical relevance no longer just inferred: Andersch Björkman 2014 (ROAT) shows patients identified this way go on to develop dermatitis from twice-daily use of a cream/perfume containing oxidized linalool at concentrations as low as 0.3% (0.056% linalool hydroperoxides, ~27 µg/cm²) — inside the 0.1–2% range measured for individual fragrance ingredients in real products.
Skin allergy / Animal study
Common fragrance chemicals such as limonene (citrus) and linalool (lavender) react with air to form far stronger skin allergens; in mouse tests, oxidized limonene was about 10 times more potent than fresh limonene.
Strong evidence: Mouse LLNA potency; review of replicated data.
Information, not medical advice. See also: myths we won’t tell you.