Citations

 

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Carcinogen and Respiratory Toxicant on the list of the Chemicals and Chemical Compounds Identified by FDA as Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke and/or Aerosol 

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https://www.fda.gov/tobacco-products/products-ingredients-components/harmful-and-potentially-harmful-constituents-hphcs

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Anethole has demonstrated significant estrogenic activity in animal studies (Dhar, 1995), and has been shown to modulate reproductive pathways relevant to embryo development (da Conceição-Santos & de Figueiredo, 2026).

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1. Dhar, S. K. (1995). Anti-fertility activity and hormonal profile of trans-anethole in rats. Indian Journal of Physiology and Pharmacology, 39(1), 63–67. https://pubmed.ncbi.nlm.nih.gov/7705873/ 

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1. da Conceição-Santos, A. L., & de Figueiredo, J. R. (2026). The role of anethole in reproductive physiology and in vitro biotechnologies: A review. Reproduction in Domestic Animals, 61(1), e70176. https://doi.org/10.1111/rda.70176

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Citations

 

 

Carcinogen on the list of the Chemicals and Chemical Compounds Identified by FDA as Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke and/or Aerosol 

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https://www.fda.gov/tobacco-products/products-ingredients-components/harmful-and-potentially-harmful-constituents-hphcs

 

 

Citations

 

Documented to cause seizures in children at relatively low doses and can occur after inhalation (Kumar et al., 2019); the FDA limits camphor in OTC topical products to 11%, however, air fresheners are not subject to an equivalent FDA camphor concentration limit. Occupational agencies such as OSHA and NIOSH have established airborne exposure limits for camphor of 2 mg/m³ as an 8-hour time-weighted average (OSHA, 2017). Camphor can get in the body if ingested, inhaled, or dermally (New York City Department of Health and Mental Hygiene, n.d; New Jersey Department of Health, 2005). Camphor can also lead to hepatic and renal injury (Kumar et al., 2019). 

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1. Kumar, S., Kavitha, T. K., & Angurana, S. K. (2019). Kerosene, Camphor, and Naphthalene Poisoning in Children. Indian journal of critical care medicine: peer-reviewed, official publication of Indian Society of Critical Care Medicine, 23(Suppl 4), S278–S281. https://doi.org/10.5005/jp-journals-10071-23316

2. Occupational Safety and Health Administration. (2017). 1910.1000 TABLE Z-1—Limits for air contaminants. U.S. Department of Labor. https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TABLEZ1

3. New Jersey Department of Health. (2005). Camphor (Hazardous Substance Fact Sheet No. 0334). https://www.nj.gov/health/eoh/rtkweb/documents/fs/0334.pdf

4. New York City Department of Health and Mental Hygiene. (n.d.). Camphor. NYC Health. https://www.nyc.gov/site/doh/health/health-topics/camphor.page

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Banned in Food.

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Coumarin is a recognized fragrance allergen and has documented hepatotoxicity concerns, including liver toxicity in animal studies and liver injury in susceptible humans (Abraham et al., 2010).

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1. Abraham, K., Wöhrlin, F., Lindtner, O., Heinemeyer, G., & Lampen, A. (2010). Toxicology and risk assessment of coumarin: Focus on human data. Molecular Nutrition & Food Research, 54(2), 228–239. https://doi.org/10.1002/mnfr.200900281

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Respiratory Toxicant on the list of the Chemicals and Chemical Compounds Identified by FDA as Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke and/or Aerosol 

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https://www.fda.gov/tobacco-products/products-ingredients-components/harmful-and-potentially-harmful-constituents-hphcs

 

 

Citations

 

Documented to cause respiratory distress and seizures on inhalation (Mathew, et al., 2017; Flaman, et al., 2001). In fact, “inhalation results in faster onset of central nervous system (CNS) symptoms because inhaled volatile oils are known to reach the brain directly and stimulate the neurons” (Mathew, et al., 2017). It is also not recommended to use during pregnancy or breastfeeding (Klein-Schwartz, n.d.).

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1. Mathew, T., Kamath, V., Kumar, R. S., Srinivas, M., Hareesh, P., Jadav, R., & Swamy, S. (2017). Eucalyptus oil inhalation-induced seizure: A novel, underrecognized, preventable cause of acute symptomatic seizure. Epilepsia Open, 2(3), 350–354. https://doi.org/10.1002/epi4.12065

2. Flaman, Z., Pellechia-Clarke, S., Bailey, B., & McGuigan, M. (2001). Unintentional exposure of young children to camphor and eucalyptus oils. Paediatrics & Child Health, 6(2), 80–83. https://doi.org/10.1093/pch/6.2.80

3. Klein-Schwartz, W. (n.d.). Eucalyptus oil: Is it safe? Poison Control. https://www.poison.org/articles/eucalyptus-oil

 

Citations

 

 

Carcinogen on the list of the Chemicals and Chemical Compounds Identified by FDA as Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke and/or Aerosol 

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https://www.fda.gov/tobacco-products/products-ingredients-components/harmful-and-potentially-harmful-constituents-hphcs

 

 

A synthetic musk that has been detected in postmortem human brain (Baumer et al., 2021) and functions as an androgen endocrine disruptor that alters reproductive organ development (Li & Wang, 2023; Wang, et al., 2023). It has also been shown to promote metastatic behavior in glioblastoma cancer cell lines (Doğanlar et al., 2021). Galaxolide is classified as persistent and bioaccumulative and has been detected in human breast milk and adipose tissue. It is under regulatory review in the EU but remains unregulated in U.S. air fresheners.

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1. Baumer, A., Jäsch, S., Ulrich, N., Bechmann, I., Landmann, J., Stöver, A., & Escher, B. I. (2021). Chemical mixtures in human post-mortem tissues assessed by a combination of chemical analysis and in vitro bioassays after extraction with silicone. Environment international, 157, 106867. https://doi.org/10.1016/j.envint.2021.106867

2. Li, M., & Wang, P. (2023). Adverse effect of environmental androgenic compounds Galaxolide and Irgacure 369 on the male reproductive system. Reproductive toxicology (Elmsford, N.Y.), 122, 108477. https://doi.org/10.1016/j.reprotox.2023.108477

3. Doğanlar, O., Doğanlar, Z. B., Chasan, T., & Kurtdere, A. K. (2021). Prolonged sub-lethal exposure to galaxolide (HHCB) and tonalide (AHTN) promotes the metastatic potential of glioblastoma tumor spheroids. NeuroToxicology, 87, 219–230. https://doi.org/10.1016/j.neuro.2021.10.006

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Classified as a reproductive toxicant and banned from EU and UK cosmetics since March 2022. The EU’s Scientific Committee on Consumer Safety specifically noted that inhalation-based exposures, may raise greater concern than topical use. Lilial remains unregulated in U.S. commercial fragrance products.

 

 

1. Limonene Emissions: Do Different Types Have Different Biological Effects?

https://pubmed.ncbi.nlm.nih.gov/34639805/

“Limonene is one of the most abundant pollutants indoors, and it contributes to the formation of additional pollutants, such as formaldehyde and photochemical smog. Limonene is commonly used in fragranced consumer products, such as cleaning supplies and air fresheners, which have also been associated with health problems. Limonene can exist in different enantiomeric forms (R-limonene and S-limonene) and be derived from different sources. However, little is known about whether different forms and sources of limonene may have different effects.” 

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2. Oxidized limonene and oxidized linalool - concomitant contact allergy to common fragrance terpenes

https://pubmed.ncbi.nlm.nih.gov/26918793/ 

"Limonene and linalool are common fragrance terpenes. Both oxidized R-limonene and oxidized linalool have recently been patch tested in an international setting, showing contact allergy in 5.2% and 6.9% of dermatitis patients, respectively.  The majority of the patients (75%) reacted to only one of the oxidation mixtures, thus supporting the specificity of the reactions. The concomitant reactions to the two fragrance allergens suggest multiple sensitizations, which most likely reflect the exposure to the different fragrance materials in various types of consumer products. This is in accordance with what is generally seen for patch test reactions to fragrance materials."

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3. Positive patch test reactions to oxidized limonene: exposure and relevance

https://pubmed.ncbi.nlm.nih.gov/25099087/ 

"Oxidized R-limonene is a common fragrance allergen, and limonene was frequently found in the labelling on the patients' products, and assessed as relevant for the patients' dermatitis. A large number of domestic and occupational sources for contact with R-limonene were identified."

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4. Fragrances: Contact Allergy and Other Adverse Effects

https://pubmed.ncbi.nlm.nih.gov/31433384/

"For diagnosing fragrance sensitization, personal products and a fragrance series may need to be tested in addition to the baseline series. In the general adult population, up to 4.5% may be allergic to fragrance materials, and in consecutive patients patch tested for suspected contact dermatitis, the frequency may reach 20% to 25%. More than 150 fragrances have caused contact allergy. The most frequent sensitizers are linalool and limonene hydroperoxides, hydroxyisohexyl 3-cyclohexene carboxaldehyde, treemoss and oakmoss absolute, isoeugenol, cinnamyl alcohol, and cinnamal. Culprit products for induction of sensitization are often deodorants, fine fragrances, and aftershaves. Occupational contact dermatitis from fragrances is seen occasionally. Other adverse effects are all discussed but occur infrequently."

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5. Allergic Contact Dermatitis to Fragrances

https://pubmed.ncbi.nlm.nih.gov/32475515/

"Allergic contact dermatitis to fragrance is common. The prevalence of fragrance allergy in the general population is between 0.7% and 2.6%. In patch-test populations, the positive reaction rate to fragrances ranges from 5% to 11%. The most common fragrance screeners in most baseline series include fragrance mix 1, fragrance mix 2, and Balsam of Peru. The addition of hydroxyisohexyl 3-cyclohexene carboxaldehyde, hydroperoxides of limonene, and hydroperoxides of linalool to screening series can further aid in the diagnosis of fragrance allergy. In the proper clinical setting, supplemental patch testing with an additional fragrance or essential oil series should be considered."

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6. Non-mix fragrances are top sensitizers in consecutive dermatitis patients - a cross-sectional study of the 26 EU-labelled fragrance allergens

https://pubmed.ncbi.nlm.nih.gov/28511284/ 

“Of 6004 patients, 940 (15.7%, 95%CI: 14.7-16.6%) were fragrance-sensitized. Regarding the single fragrances, most patients were sensitized to Lin-OOH (3.9%), Evernia furfuracea (3.0%), Lim-OOH (2.5%), and hydroxyisohexyl 3-cyclohexene carboxaldehyde (2.1%). Significantly fewer patients were 'FM I-positive and constituent-positive' than 'FM II-positive and constituent-positive' (32.7% versus 57.0%, p < 0.0001). Additionally, significantly more patients were 'FM II-negative but constituent-positive' than 'FM I-negative but constituent-positive' (12.4% versus 3.2%, p = 0.0008).”

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7. Limonene hydroperoxide analogues differ in allergenic activity

https://pubmed.ncbi.nlm.nih.gov/19076885/ 

“A marked increase in the sensitizing potency of ox. limonene compared with that of pure limonene was observed in the LLNA. One analogue, limonene-1-hydroperoxide, was a significantly more potent sensitizer than the other hydroperoxides and gave more positive test reactions in the allergic patients. The results support that hydroperoxides have a specific reactivity indicating that oxygen-centred radicals are important in hapten-protein complex formation of hydroperoxides. The primary oxidation products of ox. limonene, the hydroperoxides, have an important impact on the sensitizing capacity of the oxidation mixture.”

 

1. Linalool--a significant contact sensitizer after air exposure. 

https://pubmed.ncbi.nlm.nih.gov/20136877/  

“Linalool is a widely used fragrance terpene. Pure linalool is not allergenic or a very weak allergen, but autoxidizes on air exposure and the oxidation products can cause contact allergy.  Raising the patch test concentration for ox. linalool gave a better detection of contact allergy, as many as 5-7% positive patch test reactions were detected. We suggest a patch test concentration of ox. linalool 6.0% pet. for future patch testing, giving a dose per unit area of 2.4 mg/cm(2) when 20 mg test substance is tested in small Finn Chambers.”

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2. Oxidized limonene and oxidized linalool - concomitant contact allergy to common fragrance terpenes

https://pubmed.ncbi.nlm.nih.gov/26918793/     

“Limonene and linalool are common fragrance terpenes. Both oxidized R-limonene and oxidized linalool have recently been patch tested in an international setting, showing contact allergy in 5.2% and 6.9% of dermatitis patients, respectively.  The majority of the patients (75%) reacted to only one of the oxidation mixtures, thus supporting the specificity of the reactions. The concomitant reactions to the two fragrance allergens suggest multiple sensitizations, which most likely reflect the exposure to the different fragrance materials in various types of consumer products. This is in accordance with what is generally seen for patch test reactions to fragrance materials.”

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3. Fragrances:Contact Allergy and Other Adverse Effects 

https://pubmed.ncbi.nlm.nih.gov/31433384/       

“For diagnosing fragrance sensitization, personal products and a fragrance series may need to be tested in addition to the baseline series. In the general adult population, up to 4.5% may be allergic to fragrance materials, and in consecutive patients patch tested for suspected contact dermatitis, the frequency may reach 20% to 25%. 

…More than 150 fragrances have caused contact allergy. The most frequent sensitizers are linalool and limonene hydroperoxides, hydroxyisohexyl 3-cyclohexene carboxaldehyde, treemoss and oakmoss absolute, isoeugenol, cinnamyl alcohol, and cinnamal. Culprit products for induction of sensitization are often deodorants, fine fragrances, and aftershaves.”
(Note: Since lotions, hair products and laundry products now smell stronger than many fine fragrances, it stands to reason that they should also be included in further testing)

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4. Allergic Contact Dermatitis to Fragrances

https://pubmed.ncbi.nlm.nih.gov/32475515/ 

"Allergic contact dermatitis to fragrance is common. The prevalence of fragrance allergy in the general population is between 0.7% and 2.6%. In patch-test populations, the positive reaction rate to fragrances ranges from 5% to 11%. The most common fragrance screeners in most baseline series include fragrance mix 1, fragrance mix 2, and Balsam of Peru. The addition of hydroxyisohexyl 3-cyclohexene carboxaldehyde, hydroperoxides of limonene, and hydroperoxides of linalool to screening series can further aid in the diagnosis of fragrance allergy. In the proper clinical setting, supplemental patch testing with an additional fragrance or essential oil series should be considered."
 

5. Selected oxidized fragrance terpenes are common contact allergens

https://pubmed.ncbi.nlm.nih.gov/15932583/

“Terpenes are widely used fragrance compounds in fine fragrances, but also in domestic and occupational products. Terpenes oxidize easily due to autoxidation on air exposure. Previous studies have shown that limonene, linalool and caryophyllene are not allergenic themselves but readily form allergenic products on air-exposure. This study aimed to determine the frequency and characteristics of allergic reactions to selected oxidized fragrance terpenes other than limonene. In total 1511 consecutive dermatitis patients in 6 European dermatology centres were patch tested with oxidized fragrance terpenes and some oxidation fractions and compounds. Oxidized linalool and its hydroperoxide fraction were found to be common contact allergens. Of the patients tested, 1.3% showed a positive reaction to oxidized linalool and 1.1% to the hydroperoxide fraction. About 0.5% of the patients reacted to oxidized caryophyllene whereas 1 patient reacted to oxidized myrcene. Of the patients reacting to the oxidized terpenes, 58% had fragrance-related contact allergy and/or a positive history for adverse reaction to fragrances. Autoxidation of fragrance terpenes contributes greatly to fragrance allergy, which emphasizes the need of testing with compounds that patients are actually exposed to and not only with the ingredients originally applied in commercial formulations.”

 

Carcinogen on the list of the Chemicals and Chemical Compounds Identified by FDA as Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke and/or Aerosol 

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https://www.fda.gov/tobacco-products/products-ingredients-components/harmful-and-potentially-harmful-constituents-hphcs

 

Carcinogen on the list of the Chemicals and Chemical Compounds Identified by FDA as Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke and/or Aerosol 

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https://www.fda.gov/tobacco-products/products-ingredients-components/harmful-and-potentially-harmful-constituents-hphcs

 

Carcinogen on the list of the Chemicals and Chemical Compounds Identified by FDA as Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke and/or Aerosol 

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https://www.fda.gov/tobacco-products/products-ingredients-components/harmful-and-potentially-harmful-constituents-hphcs

 

Carcinogen and Respiratory Toxicant on the list of Chemicals and Chemical Compounds Identified by FDA as Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke and/or Aerosol 

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https://www.fda.gov/tobacco-products/products-ingredients-components/harmful-and-potentially-harmful-constituents-hphcs

Trace residual solvent from botanical extraction

Respiratory Toxicant on the list of Chemicals and Chemical Compounds Identified by FDA as Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke and/or Aerosol 

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https://www.fda.gov/tobacco-products/products-ingredients-components/harmful-and-potentially-harmful-constituents-hphcs

 

An OSHA recognized “Hazardous Chemical,” and respiratory hazard with an OSHA PEL of 100ppm and an ACGIH limit of 20ppm, a skin sensitizer and environmental hazard. Can cause headaches, dizziness, nausea, confusion, rapid pulse and may damage the nervous system, kidneys, bladder and a developing fetus (New Jersey Department of Health and Senior Services, 2003). Terpenes also react with ozone to form formaldehyde, acetaldehyde, and ultrafine particles (IARC, 2006; Patra et al., 2024).

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1. New Jersey Department of Health. (2003). Turpentine, oil (Hazardous Substance Fact Sheet No. 1962). https://nj.gov/health/eoh/rtkweb/documents/fs/1962.pdf

2. International Agency for Research on Cancer (IARC). (2006). Formaldehyde, 2-butoxyethanol and 1-tert-butoxypropan-2-ol (IARC Monographs, Vol. 88). WHO. https://publications.iarc.who.int/106

3. Patra, S. S., Liu, J., Jiang, J., Ding, X., Huang, C., Keech, C., Steiner, G., Stevens, P. S., Jung, N., & Boor, B. E. (2024). Rapid Nucleation and Growth of Indoor Atmospheric Nanocluster Aerosol during the Use of Scented Volatile Chemical Products in Residential Buildings. ACS ES&T Air, 1(10), 1276–1293. https://doi.org/10.1021/acsestair.4c00118

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Citations