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
Two no-lye hair relaxer kits marketed for children had the highest measured levels of chemicals banned in EU cosmetics or listed under California's Proposition 65 (DEHP, nonylphenol, o-phenylphenol, diethanolamine) of any products tested in this study.
Moderate evidence: N=3 relaxer kits (2 marketed for children); no health outcome measured in children who used these products.
Children and pregnancy / Measured in people or real products
In a Czech birth cohort of 3,411 children (ELSPAC-CZ), each 1-SD increase in an 18-product household chemical exposure score measured at 6 months raised the odds of intermediate-onset transient wheeze (adjusted OR 1.27), early-onset persistent wheeze (adjusted OR 1.36) and intermediate-onset persistent wheeze (adjusted OR 1.23) through age 5, and those persistent wheeze phenotypes carried 5-8x higher odds of a doctor-diagnosed asthma by age 7 (pediatrician records, not self-report).
Moderate evidence.
Caveats
Single prospective cohort; exposure and wheeze through age 5 are maternal self-report (only the school-age asthma outcome is medically ascertained); the asthma link runs through the wheeze phenotype, not directly from exposure to asthma, and the paper's own direct exposure-to-asthma model was underpowered. Independently replicates the Canadian CHILD cohort (Parks 2020), which together raises the combined wheeze/asthma claim to strong (see regrade on src-2024-cleaning-products-chemistry-indoor-air-quality-health).
Source: Mikeš 2019, Science of the Total Environment Link to this fact
Children and pregnancy / Self-reported survey
Teenage girls reported chemical sensitivity about twice as often as boys (20.6% vs 9.9%), and being female, being sensitive to noise, or having probable anxiety each roughly doubled the odds of reporting it.
Moderate evidence: Logistic regression with low explanatory power (Nagelkerke R2=0.092); only modeled for the general-CS outcome.
Source: Andersson 2008, International Journal of Hygiene and Environmental Health Link to this fact
Children and pregnancy / Review of other studies
The developing fetal and infant brain is far more vulnerable to industrial-chemical injury than the adult brain: the placenta is not an effective barrier to most industrial chemicals, the blood-brain barrier is not fully formed until about 6 months after birth, and lipophilic persistent chemicals concentrate in breast milk at up to 100-fold the mother's bodyweight-adjusted exposure.
Moderate evidence.
Caveats
General toxicological vulnerability argument for industrial chemicals (lead, methylmercury, PCBs, arsenic, toluene are the paper's 5 confirmed causes); does not measure or name any fragrance ingredient. Should not be cited as fragrance-specific evidence.
Source: Grandjean & Landrigan 2006, Lancet Link to this fact
Children and pregnancy / Measured in people or real products
In 101 Swedish first-time mothers tested over seven years, women who used perfume once a week or more had significantly higher levels of the musk chemical galaxolide (HHCB) in their breast milk than women who used it less often.
Moderate evidence: Product-use data from a N=44 subset; cross-sectional association, not an intervention; adjusted for sampling year.
Source: Lignell 2008, Environmental Science & Technology Link to this fact
Children and pregnancy / Measured in people or real products
Mothers who used perfumed laundry detergent had significantly higher levels of the musk chemical tonalide (AHTN) in their breast milk than mothers who used unscented detergent.
Moderate evidence: Product-use data from a N=44 subset; cross-sectional association, not an intervention; adjusted for sampling year.
Source: Lignell 2008, Environmental Science & Technology Link to this fact
Children and pregnancy / Other evidence
In 1998, EPA's own pesticide-program administrator reported that, per an outside audit of a random 100-chemical sample, 71% of the roughly 3,000 highest-volume industrial chemicals in US commerce had no basic toxicity data publicly available at all, and 63% had not been tested for carcinogenicity.
Moderate evidence.
Caveats
A single external audit (Environmental Defense Fund), not independently replicated or EPA's own primary tabulation; concerns industrial chemicals in general, not fragrance or consumer products specifically.
Source: Goldman 1998, Environmental Health Perspectives Link to this fact
Children and pregnancy / Self-reported survey
In a large UK birth cohort (ALSPAC, n=7,019), each 1-unit increase in a composite score of prenatal household chemical product use (11 products, frequency-weighted) raised the odds of persistent wheeze through age 3.5 by 6% (adjusted OR 1.06, 95% CI 1.03-1.09), and children of mothers in the top decile of use were more than twice as likely to wheeze persistently as those in the bottom decile (adjusted OR 2.3, 95% CI 1.2-4.4); transient early wheeze and late onset wheeze showed no significant adjusted association.
Moderate evidence.
Caveats
Observational; both exposure (product-use frequency) and outcome (parent-reported wheeze) are questionnaire-based, with no objective air-chemistry or clinical measurement. The persistent-wheeze specificity (no significant transient-early or late-onset association) is the same phenotype-specific pattern later independently replicated in the Czech ELSPAC-CZ cohort (Mikes 2019) and, more broadly, in the Canadian CHILD cohort (Parks 2020). Graded moderate (orchestrator 2026-09-27): one cohort, self-report on both sides; the cross-cohort replication is credited on the pooled four-cohort claim instead.
Children and pregnancy / Other evidence
No controlled human exposure studies investigating whether children, elderly people, or smokers are more sensitive to irritant chemicals than healthy young adults could be found in the literature through August 2020.
Moderate evidence: Absence of studies, not evidence of no difference; the same evidence gap for children is documented in more detail by a later 2024 review.
Source: Mangelsdorf et al. 2021, Int J Hyg Environ Health, International Journal of Hygiene and Environmental Health Link to this fact
Children and pregnancy / Government agency
Exposure to hormone-disrupting chemicals during fetal development, infancy, and puberty can permanently reprogram how tissues develop, with effects that may not become visible until years or decades later; children are considered the most vulnerable population because of their hand-to-mouth behavior and higher metabolic rate.
Moderate evidence: This is the report's general developmental-programming framework, illustrated mainly with lead, PCBs, DES, and pesticides, not with fragrance chemicals.
Source: WHO/UNEP 2012 Link to this fact
Children and pregnancy / Review of other studies
Phthalates such as DEHP are not chemically bound to PVC medical devices, so they continuously leach out of them; the US FDA issued a public health warning about DEHP in medical devices in 2001, and NICU neonates can receive DEHP exposure up to 20 times the tolerable daily intake from medical devices.
Moderate evidence.
Caveats
The review describes 'medical devices' generally, of which PVC IV tubing and blood bags are the classic DEHP-plasticized examples, but does not itself name 'IV tubing' or 'blister medication packaging' specifically, nor does it quantify leaching directly into the bloodstream during an infusion. NICU neonates are the most intensively studied, highest-exposure population — this figure should not be generalized to routine adult outpatient IV use without further support.
Source: Latini/Italian review 2006, Toxicology Link to this fact
Children and pregnancy / Measured in people or real products
In 20 Korean mothers, the synthetic musk fragrance chemical galaxolide (HHCB) was found in 70% of umbilical cord blood samples, often at levels higher than in the mother's own blood, pointing to the placenta, not just breast milk, as a route by which fragrance musks reach a baby.
Moderate evidence.
Caveats
Single Korean cohort, n=20 cord sera (17 complete mother-infant-milk triads); the authors call it a preliminary study. No product-use data collected, so the exposure source (cosmetics, laundry, etc.) is inferred, not measured. The paper's own text and its own table/summary numbers disagree on whether maternal or cord serum is higher, though both clearly exceed breast milk.
Children and pregnancy / Measured in people or real products
In 42 Chinese mother-infant pairs, synthetic musk fragrance chemicals (especially galaxolide/HHCB) were found in 95% of 126 paired maternal blood, umbilical cord blood, and breast milk samples.
Moderate evidence.
Caveats
One city (Shanghai), 2007 samples, n=42 pairs; no product-use data; no health outcome; detection rates in blood were much lower (12-18 of 42) than in milk (41/42), limiting precision for the blood matrices.
Source: Zhang 2015, International Journal of Hygiene and Environmental Health Link to this fact
Children and pregnancy / Measured in people or real products
Musk fragrance levels in a newborn's own umbilical cord blood were higher than in the mother's blood, showing these scent chemicals cross the placenta before birth and can accumulate more in the fetus than in the mother.
Moderate evidence.
Caveats
Median total musk (ng/g lipid weight): cord serum 87.3 vs maternal serum 71.2 in this 42-pair Shanghai cohort; independently matches the direction (not the magnitude) found in a separate 20-pair South Korean cohort (Kang 2010), though Kang 2010's own paper is internally inconsistent about this direction in its prose vs its own tables.
Source: Zhang 2015, International Journal of Hygiene and Environmental Health Link to this fact
Children and pregnancy / Measured in people or real products
The ratio of a common fragrance musk chemical (HHCB/galaxolide) in cord blood versus the mother's blood was consistently and significantly above 1, which does not match what simple passive diffusion across the placenta would predict, hinting at an active or facilitated transfer process that is not yet understood.
Moderate evidence.
Caveats
Based on 17-40 valid paired samples (after excluding non-detects and statistical outliers) from one 42-pair Shanghai cohort; no transporter or protein-binding mechanism was directly tested; the authors call their own suggestion preliminary.
Source: Zhang 2015, International Journal of Hygiene and Environmental Health Link to this fact
Children and pregnancy / Other evidence
A 2020 review summarizing human studies reports that chemicals such as phthalates, parabens, triclosan, PFAS, PCBs, and flame retardants were detected in 99-100% of pregnant women's samples in one US survey, and that levels were no different from non-pregnant women.
Moderate evidence: Secondary summary of cited biomonitoring studies; detection is not health effect; mixtures of 'EDCs' not fragrance-specific.
Source: Street 2020, International Journal of Molecular Sciences Link to this fact
Children and pregnancy / Other evidence
The review states the placenta does not block many environmental toxicants, that more than 200 foreign chemicals have been found in umbilical cord blood, and that many chemicals pass to infants in breast milk.
Moderate evidence: The cord-blood count comes from an advocacy-organization report cited secondhand; presence in cord blood does not by itself show harm.
Source: Grandjean & Landrigan 2014, Lancet Neurology, The Lancet Neurology Link to this fact
Children and pregnancy / Animal study
The Endocrine Society's 2015 statement says fetal and infant exposure to hormone-disrupting chemicals can cause latent disease later in life, and that human studies support lower IQ and cognitive deficits in children exposed prenatally to certain thyroid-disrupting chemicals.
Moderate evidence.
Caveats
No compound-specific numbers; the authors note exposure is 'not always correlated' with lower thyroid hormone in humans, and that serum thyroid hormone may not reflect tissue action.
Source: Gore et al. 2015, Endocr Rev 36(6):593-602, Endocrine Reviews Link to this fact
Children and pregnancy / Other evidence
A 2016 consensus statement signed by 47 scientists, clinicians and advocates (Project TENDR) named organophosphate pesticides, PBDE flame retardants, combustion air pollution, lead, mercury and PCBs as chemicals whose neurodevelopmental toxicity it says epidemiological, toxicological and mechanistic studies clearly demonstrate or strongly suggest.
Moderate evidence: The grading is the signatories' own; no systematic review method is described, and the group includes NGO employees. Funded by foundations and NIEHS, not industry.
Source: Bennett et al. 2016 (TENDR Consensus Statement, EHP), Environmental Health Perspectives Link to this fact
Children and pregnancy / Other evidence
The 2016 TENDR statement described phthalates only as an 'emerging concern' for brain development, not as a chemical with clearly demonstrated neurodevelopmental toxicity, and did not mention fragrance.
Moderate evidence: Later TENDR work (Engel 2021) takes a stronger position on ortho-phthalates; this is the same group's earlier wording.
Source: Bennett et al. 2016 (TENDR Consensus Statement, EHP), Environmental Health Perspectives Link to this fact
Children and pregnancy / Other evidence
The TENDR statement cited a 2011 analysis of US CDC biomonitoring data finding that 90% of pregnant women had detectable levels of 62 of the 163 chemicals screened, including PBDEs, PAHs, phthalates, perfluorinated compounds, PCBs, perchlorate, lead and mercury.
Moderate evidence: Secondary citation; detection does not indicate harm, and the data are from 2003-2004.
Source: Bennett et al. 2016 (TENDR Consensus Statement, EHP), Environmental Health Perspectives Link to this fact
Children and pregnancy / Review of other studies
A 2024 narrative review of thyroid and environmental contaminants concludes that studies of chemicals and thyroid function are scarce for pregnancy, the newborn period and childhood, and that the evidence on bisphenols and phthalates is not yet complete across ages and critical windows.
Moderate evidence: Narrative review without grading or counts; it summarizes single cited studies.
Source: Street 2024, Front Endocrinol, Frontiers in Endocrinology Link to this fact
Children and pregnancy / Other evidence
A cited 32-cohort meta-analysis found prenatal organochlorine and PFAS exposure associated with lower neonatal total T4 (not TSH in neonates for the PFAS mixture), the strongest design in this review's chemical section.
Moderate evidence: Relayed by the review, not re-analyzed; PFAS and organochlorines are not fragrance chemicals.
Source: Street 2024, Front Endocrinol, Frontiers in Endocrinology Link to this fact
Children and pregnancy / Other evidence
In 695 mother-child pairs from two North American birth cohorts (HOME and MIREC), a mixture of 29 chemical biomarkers measured in early pregnancy was not statistically linked to behavior problems at age 3: every overall confidence interval for the joint effect included zero.
Moderate evidence: Single spot biomarkers, parent-reported scales, no multiplicity correction; the authors call the results suggestive but imprecise.
Source: Puvvula 2026, Environ Int, Environment International Link to this fact
Children and pregnancy / Review of other studies
The same review reports that age, BMI, smoking, parity and gestational age had poor ability to predict overt or subclinical hypothyroidism in pregnancy, and that factors such as iron deficiency, obesity, ethnicity and endocrine-disrupting chemicals are emerging factors with weak predictive power for screening.
Moderate evidence: Predictive value for screening is not the same as causal contribution; the chemicals were not separately graded.
Information, not medical advice. See also: myths we won’t tell you.