The Impact of Junk Science on R&D: A Review of the 'Dirty Dozen'

Last spring, the David Suzuki Foundation, an environment conservation group based in Vancouver, published a report online describing what it called the “dirty dozen” cosmetic ingredients consumers should avoid.¹ The group went so far as to provide a downloadable pocket guide of the 12 ingredients for consumers to use when they shop to avoid purchasing products containing these ingredients. Normally this column would not cover the faulty and misleading junk science of non-governmental organizations (NGOs); however, with current political activity in the US Congress, i.e. the introduction of the Safe Cosmetics Act of 2010, the industry should be aware of what it is facing.

In addition, marketing is well aware of consumers’ perceptions of ingredients, which in turn are passed on to R&D with the directive to omit those that are negatively viewed for “free-from” product claims. Thus, the information presented here supports both R&D and marketing by providing the solid facts behind these 12 ingredients; but since consumer perception ultimately determines success, if this effort to present sound science is futile, it may simply offer R&D a forecast of the ingredients that eventually will require replacing.

The David Suzuki Foundation is a registered charitable organization in the United States and Canada that was established in 1990 to deal with environmental issues. Due to its well-respected status, this author was surprised to see such faulty science reported by this group, as each individual ingredient description below illustrates. Following are the 12 ingredients identified, including comments from the foundation website, with additional facts about each that should have been included. Also included is the frequency of use for each ingredient, based on the US Food and Drug Administration’s (FDA) database of some 36,811 registered formulations.

BHA or BHT

According to the foundation report: Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are used mainly in moisturizers and makeup as antioxidants and preservatives. They are also a hidden ingredient in some fragrances. BHA is toxic to the immune system and the International Agency for Research on Cancer classifies it as a possible human carcinogen. Studies suggest that BHT may be toxic to the skin, lungs, liver and immune system. Both chemicals can cause allergic reactions, are suspected of interfering with hormone function (endocrine disruption), and may promote tumor growth. They also have the potential to bio-accumulate in aquatic species.

Facts: While BHA and BHT are antioxidants, they are used primarily in foods where they are generally recognized as safe (GRAS) by the FDA at up to 0.02% fat content.^{2, 3} The Personal Care Products Council Cosmetic Ingredient Review (CIR) found the materials to be safe as cosmetic ingredients; however, BHA is listed in California’s Proposition 65 legislation, so its use in cosmetics is declining. Based on the FDA database, BHA is currently included in 905 registered formulations while BHT is in 4,890.

Replacement ingredients: When a fat or vegetable oil is oxidized, i.e. turns rancid, it produces an unpleasant odor. Therefore, antioxidants are used to prevent unsaturated compounds from oxidizing. Alternative antioxidants to BHA and BHT include propyl gallate and tert-butylhydroquinone (TBHQ). Tocopherol, also known as vitamin E, is another option that would be considered the natural alternative. It is a brownish colored liquid used typically at 1.0% to achieve the same efficacy as 0.02% of BHT. In most cases, this material is used in products so that vitamin E can be used on the label, although the word tocopherol must be used in the ingredient disclosure.

Coal Tar Dyes

The foundation also cautions consumers to look for p-phenylenediamine or colors identified as “C.I.” followed by a 5-digit number. According to the group: phenylenediamine, used in hair dyes, has been found to be carcinogenic in laboratory tests conducted by the US National Cancer Institute and National Toxicology Program. Other coal tar-derived colors are used extensively in cosmetics, identified by a five-digit Color Index (CI) number. The US color name may also be listed (“FD&C” or “D&C” followed by a color name and number). Coal tar itself is recognized as a human carcinogen and the main concern with coal tar colors are their potential as carcinogens. As well, colors may be contaminated with low levels of heavy metals and some contain aluminum (a neurotoxin). This is of particular concern when used in cosmetics that may be ingested, like lipstick.

Facts: As most chemists know, p designates para, which is different from m or meta; thus materials designated by p and m are different chemicals. p-Phenlyenediamine is permitted in the European Union (EU) whereas m-phenylenediamine is prohibited, and it is p-phenylenediamine that is used as a precursor for hair dyes. In addition, p-phenylenediamine was reviewed by the CIR, which concluded that p-phenylenediamine, p-phenylenediamine HCI and p-phenylenediamine sulfate are safe for use as hair dyes based on the practices of use and concentration described in the safety assessment.⁴ The material also has been reviewed by the EU’s safety committee and added to Annex III of the EU Cosmetic Directive as being safe at up to 2% total, i.e. for both components of the hair dye process mixed, with the required warnings and directions. Based on FDA numbers, the total registered formulations containing p-phenylenediamine number 1,780.

Regarding CI numbers, the EU uses the letters CI followed by a 5-digit number as its nomenclature for colors. There currently are 144 colors with CI numbers approved for use in cosmetics in the EU. There are also 11 colors identified by name. It should be noted that chemicals having CI numbers are not necessarily allowed for use as colorants in cosmetics. The two critical ones are mica and tin oxide. Although they can be identified by CI numbers, these materials are not approved as colorants for cosmetics and may therefore not be listed in the “may contain” section of the product ingredient declaration.

In the United States, the names of colors are assigned by the FDA. Whereas the CI system assigns a different number to each shade of iron oxide black, yellow, red and brown, the FDA calls them all iron oxides. Like the EU, the FDA allows the dual labeling of colors, so both the FDA color name and CI number often appear on product labels; i.e., Blue 1 (CI 42090) or CI 42090 (Blue 1).

All colors allowed in the EU and the United States must also be approved for use as colorants in cosmetics. To be approved, colorants undergo a long safety review. The United States divides approved colors into two categories; certified colors and batch certified colors. Most organic dyes are batch certified, which means the FDA tests each batch before it can be used. The other colors are certified by manufacturers that meet the FDA’s published specifications. Table 1 lists the colors with CI numbers that are allowed in the United States and EU; note that lakes are not included in this list. Those colors listed here have been pre-approved for their intended use, i.e. in cosmetics.

In reference to the group’s comments on aluminum, this material is found in lakes. Lakes are batch certified colors that are precipitated to form FDA-approved substrates. These insoluble pigments are used in color cosmetics including lipsticks, eye shadows, etc. In this author’s view, the writer of the report did not understand the major and significant differences between hair dye intermediates and colorants used in cosmetics.

Diethanolamine (DEA)

The foundation also includes DEA on its list, stating that: DEA (diethanolamine) and DEA compounds are used to make cosmetics creamy or sudsy. They irritate the skin and eyes and may be toxic to the immune and nervous systems. DEA compounds can also react with other ingredients in cosmetics to form carcinogenic nitrosamines. The Danish Environmental Protection Agency classifies cocamide DEA as hazardous to the environment because of its acute toxicity to aquatic organisms and potential for bioaccumulation

Facts: DEA, MEA and TEA are not found in cosmetic products. All three are strong bases used to neutralize acids to form salts. Examples of this are TEA stearate, a common emulsifier that is frequently made in situ to form o/w emulsions; and DEA cetyl phosphate, a common emulsifier for sunscreens. MEA and DEA are used as chemical reactants to form alkanolamides such as cocamide DEA and cocamide MEA, which are used in foaming products such as shampoos, cleansers, washes, etc. to increase the viscosity and stability of foam.

The EU has prohibited the use of DEA and its salts in cosmetics, although trace amounts are allowed in alkanolamides. The CIR reviewed these materials and concluded that TEA, DEA and MEA are safe for use in cosmetic formulations designed for discontinuous and brief use, followed by thoroughly rinsing them from the skin.⁵ In products intended for prolonged contact with the skin, ethanolamines should not exceed 5% w/w, and MEA should only be used in rinse-off products. Finally, TEA and DEA should not be used in products containing N-nitrosating agents⁶ but contrary to the foundation’s statement, N-nitrosating agents are not used in cosmetics.

According to the FDA database, the current number of formulations containing these materials is: 30 with DEA, 0 with MEA and 4,012 with TEA. In addition, the number of formulas containing ingredients with these materials in their INCI name is: 1,732 with DEA, mostly alkanolamides; 1,721 with MEA, again, mostly alkanolamides; and 778 with TEA, and most are salts used as soaps or other foaming agents. While many other neutralizing agents can be used in place of these materials, they typically are more expensive.

Dibutyl Phthalate

According to the foundation, dibutyl phthalate is mainly used in nail products as a solvent for dyes and as a plasticizer that prevents nail polishes from becoming brittle. Phthalates are also unlisted fragrance ingredients in many other cosmetics. Dibutyl phthalate is absorbed through the skin. It can enhance the capacity of other chemicals to cause genetic mutations, although it is not a mutagen itself. In laboratory experiments, it has been shown to interfere with hormone function (endocrine disruption) causing reproductive and developmental problems. Dibutyl phthalate is banned in cosmetics in the EU, but not in Canada.

Facts: Dibuthyl phthalate was a popular plasticizer for nail polish but was prohibited by the EU and added to California’s Proposition 65 list even though it was deemed safe for this use. The CIR found⁷ the material to be safe in 1985 and in 2005, decided that there was no reason to review this opinion again. Although dibutyl phthalate is not absorbed through the nail,⁸ since the state of California requires a warning on the label for products containing it, most companies are phasing out its use. Currently, the FDA database lists 42 formulations including the material.

Formaldehyde-releasing Preservatives

Next on the foundation’s list are preservatives including: DMDM hydantoin, diazolidinyl urea, imidazolidinyl urea, methenamine, quarternium-15 and sodium hydroxymethylglycinate. According to the report, these formaldehyde-releasing agents are used as preservatives in cosmetics. Formaldehyde is a recognized human carcinogen. DMDM hydantoin and quarternium-15 can irritate skin and eyes and trigger allergies at low doses. They are also toxic to aquatic organisms.

Facts: Formaldehyde (CAS 50-00-0, EINECS 200-001-8) is an anhydrous gas that is not found in cosmetics and not released by any of the listed preservatives.⁹ What is released is a completely different chemical known as methylene glycol (CAS CAS 463-57-0, EINECS 207-339-5), which has different chemical and safety profiles. All the listed preservatives have been reviewed by the CIR and found to be safe for use as preservatives in cosmetics.¹⁰ These materials have also been reviewed by the EU and are on the list of permitted preservatives. The FDA database currently lists the following numbers of formulas containing these materials: 2,035 with DMDM hydantoin; 1,644 with diazolidinyl urea; 2,007 with imidazolidinyl urea; 6 with methenamine; 389 with quaternium-15 and 90 with sodium hydroxymethylglycinate.

Fragrance (parfum)

Fragrance or parfum on a cosmetic ingredient list, according to the report, usually represents a complex mixture of dozens of chemicals. It continues: fragrance recipes are considered a trade secret, so companies are not required to disclose fragrance chemicals in the list of ingredients. Of the thousands of chemicals used in fragrances, most have not been tested for toxicity, alone or in combination. Many of these hidden ingredients are irritants and can trigger allergic attacks, migraines and chemical-induced nerve irritation in sensitive individuals. In laboratory experiments, individual fragrance ingredients have been associated with cancer and neurotoxicity. For example, one chemical of concern is dimethyl phthalate (pronounced thal-ate), or DEP. Widely used in cosmetics to make fragrances linger, DEP is suspected of interfering with hormone function (endocrine disruption), causing reproductive and developmental problems. Health Canada recently announced regulations banning six phthalates in children’s toys, but DEP is still widely used in cosmetics.

Facts: As is generally known, besides perfumes, fragrances are used to mask odors or add scent to formulations. It is true that fragrances are complex mixtures. The latest International Fragrance Association (IFRA) survey¹¹ found that 3,163 different fragrance components are used. In addition, it is true that the industry does not have to reveal fragrance components; in fact, if it were forced to, the industry would likely cease to exist. This is because fragrances cannot be patented, so the only way to protect the intellectual property is to maintain a trade secret status. This practice has been recognized throughout the world.

The Research Institute for Fragrance Materials (RIFM) is responsible for evaluating the safety of the ingredients used in fragrances, and members are required to abide by the group’s findings to ensure safety. Further, cosmetic companies test the safety of final formulations, which include fragrances, and this provides additional information regarding safety in an actual use setting. The FDA database currently lists 23,142 formulas as containing fragrances. Once again, the David Suzuki Foundation has confused chemicals, mistaking dimethyl phthalate for diethyl phthalate. Dimethyl phthalate is not used in fragrances. Diethyl phthalate is used in fragrances and has been found safe for this application by RIFM, CIR and the EU.^12–14

Parabens

According to the foundation, consumers should also look for ingredients ending in paraben, e.g., methylparaben. The report states: parabens are widely used in cosmetics as a preservative. They easily penetrate the skin and are suspected of interfering with hormone function (endocrine disruption). There is some evidence that parabens mimic estrogen, the primary female sex hormone. Some studies suggest a possible association between parabens and breast cancer.

Facts: The esters of parahydroxybenzoic acid are called parabens, and these are listed by the alcohol that is esterified to the acid. The safest and most commonly used esters include methylparaben, ethylparaben, propylparaben, isopropylparaben, butylparaben and isobutylparaben.¹⁵ Everything stated in the foundation’s report reflects Internet rumors and studies that have not been reproduced, or that are of little scientific value. For example, parabens have been accused of being endocrine disrupters but, being more than 100,000 times weaker than the endocrine disrupters found naturally in the human body, they do not cause any activity.¹⁶

In addition, parabens do not easily penetrate the skin unless they are dissolved in a solvent that enhances skin penetration; however, since they typically are dissolved in water for their use, penetration into the skin from cosmetic products is almost impossible to achieve. Currently, the FDA database lists the following numbers of formulas as containing these preservatives: 13,434 with methylparaben; 4,869 with ethylparaben; 10,421 with propylparaben; 336 with isopropylparaben; 5,289 with butylparaben and 2,693 with isobutylparaben. While there are replacements for parabens in some formulations, there is not an easy drop-in replacement in every case. In addition, replacements typically are more expensive and have less safety data available.

PEG Compounds

The next items to look for, according to the report, are chemical propylene glycol and other related ingredients containing the letters eth (e.g., polyethylene glycol or PEG-60). The group notes that PEG (polyethylene glycol) compounds are widely used in cream bases in cosmetics. PEG (and its chemical cousin, propylene glycol) opens the skin’s pores, allowing harmful ingredients to penetrate more deeply. PEG and other “ethoxylated” ingredients (which usually have chemical names including the letters “eth”) may be contaminated with ethylene oxide and 1,4-dioxane. Both contaminants may cause cancer. Also, ethylene oxide may harm the nervous system and interfere with human development, and 1,4-dioxane is persistent. In other words, it doesn’t easily degrade and can remain in the environment long after it is rinsed down the shower drain.

Facts: First of all, as chemists generally know, PEGs are not chemical cousins to propylene glycol (PG); these are two different types of chemistries. PEGs are polymers while PG is a simple 3-carbon atom diol. There is only one PG, while according to the PCPC INCI dictionary there are over 1,200 PEG derivatives and 46 PEG polymers. The dictionary also lists more than 900 eth ingredients that are formed by ethoxylation. The writer of the foundation’s report failed to mention all the other ingredients made from ethylene oxide. Further, ethylene oxide reacts violently with water, which makes it nearly impossible to find ethylene oxide in cosmetic products. 1,4 Dioxane is a by-product of ethoxylation but the industry has learned to reduce it to trace levels and the FDA has found no issue with the presence of these trace amounts.¹⁷ Since there are more than 2,100 ingredients in this list, their frequency of use is not included here.

Petrolatum

The foundation report states that petrolatum or mineral oil jelly is used in a variety of moisturizers as a barrier to lock moisture into the skin. It is also reported to be used in hair care products to make hair shine. The report adds: petrolatum, a petrochemical, can be contaminated with cancer-causing polycyclic aromatic hydrocarbons (PAHs). The EU considers petrolatum a carcinogen and restricts its use in cosmetics.

Facts: This interpretation of the EU regulation is the worst this author has ever seen. The EU bans petrolatum except when the full refining history is known, and when it can be shown that the substance from which the material is produced is not a carcinogen.¹⁸ Petrolatum or petroleum jelly has been used for more than 100 years topically as a drug and cosmetic ingredient as well as a lubricant. The foundation report’s writer would be hard-pressed to find a single case of cancer reported to be caused by petrolatum. Further, no US or Canadian producer of petrolatum ever has been prohibited by the EU. Based on the FDA database, there are currently 2,267 registered formulas containing petrolatum. While some ingredient suppliers are offering substitutes for this material, again, they are typically more expensive and cannot be used as equivalents in all applications.

Siloxanes

The next ingredient on the list is cyclomethicone as well as ingredients ending in siloxane, e.g., cyclotetrasiloxane. The report states: Cyclomethicone and siloxanes are used in cosmetics to soften, smooth, and moisten. These compounds can, however, irritate the skin, eyes and lungs. They are also suspected of interfering with hormone function (endocrine disruption) and of liver toxicity. These chemicals are persistent. In other words, they don’t easily degrade and can remain in the environment long after they are rinsed down the shower drain. Environment Canada considers cyclotetrasiloxane and cyclopentasiloxane to be toxic to fish and other aquatic organisms.

Facts: Both the CIR and EU have reviewed the safety of cyclotetrasiloxane and cyclopentasiloxane and neither has found studies to indicate these materials cause eye irritation, skin irritation or irritation to the lungs. If the foundation has valid scientific studies to prove these charges, this author suggests the group submit them. Environment Canada has not yet completed its work on these materials and could restrict the use of cyclotetrasiloxane since it is suspected under the Canadian Environmental Protection Act to potentially be toxic to the environment.¹⁹ This is why using the generic term cyclomethicone in ingredient listings should be avoided.

In addition to these two ingredients, the INCI dictionary lists 30 other ingredients ending in siloxane that have been approved for cosmetic use. The FDA database shows the following numbers of formulations containing these materials: 1,506 with cyclomethicone; 76 with cyclotetrasiloxane; 3,004 with cyclopentasiloxane and 759 with cyclohexasiloxane. Again, some vendors have introduced replacement ingredients for these materials to allow “free from” claims, although such claims are self-destructive to the industry, as is evidenced by this column.

Sodium Laureth Sulfate

The foundation also cautions consumers to watch for sodium lauryl sulfate and other related ingredients that include the letters eth. According to the report, sodium laureth sulfate is used in cosmetics as a cleansing agent and also to make products bubble and foam. This and other “ethoxylated” ingredients (which usually have chemical names including the letters “eth”) may be contaminated with ethylene oxide and 1,4-dioxane. Both contaminants may cause cancer. Also, ethylene oxide may harm the nervous system and interfere with human development, and 1,4-dioxane is persistent. In other words, it doesn’t easily degrade and can remain in the environment long after it is rinsed down the shower drain.

Facts: The foundation has already condemned sodium laureth sulfate (SLES) in the previous discussion on PEG compounds. Here, it has added nothing new except to relate the material to sodium lauryl sulfate (SLS). As the starting alcohol is ethoxylated, the resultant surfactant becomes more water-soluble and less irritating. Since both of these surfactants are sold as aqueous solutions, there is no chance of any non-reacted ethylene oxide being present. Currently, the FDA reports 1,428 formulations containing SLS and 3,218 containing SLES. There are also replacement materials for these ingredients that, again, are more expensive, which poses a challenge to their application in the cost-competitive shampoo market.

Triclosan

The final ingredient in the list of the “dirty dozen” is triclosan, which according to the report is used mainly in antiperspirants/deodorants, cleansers and hand sanitizers as a preservative and an antibacterial agent. It can pass through skin and is suspected of interfering with hormone function (endocrine disruption). Environment Canada categorized triclosan as potentially toxic to aquatic organisms, bioaccumulative, and persistent. In other words, it doesn’t easily degrade and can build up in the environment after it has been rinsed down the shower drain. The extensive use of this chemical in consumer products may contribute to antibiotic-resistant bacteria. The Canadian Medical Association has called for a ban on antibacterial consumer products, such as those containing triclosan.

Facts: Triclosan, as most formulators know, is used in cosmetics as an antibacterial agent in deodorants. It is not found in antiperspirants; rather, it is used as an active ingredient in over-the-counter (OTC) drugs such as toothpaste and antibacterial cleansers. In Canada, in regard to OTC use, all drugs must be pre-approved by Health Canada for safety and effectiveness. All drugs must meet an OTC Drug monograph in the United States or be approved by the FDA before being placed on the market.

Triclosan has become the number one target of NGOs, possibly due to the fact that it is used generally in OTC topicals rather than cosmetics in the United States. The CIR is currently reviewing this material. In Annex VI to the Cosmetics Directive, the EU approved the use of this material up to 0.3% with no warnings required. The number of formulations containing this ingredient, based on FDA data, is 494. In regard to replacement ingredients, this author does not believe there are any for toothpaste or antibacterial cleansers; there may be for use in deodorants.

Comments

The “dirty dozen” is really some 2,200 materials including several of the most commonly used cosmetic ingredients. If formulators were to avoid using all these materials, products would be drastically different. Imagine lipsticks and other color cosmetics made with only the permitted colors lactoflavin, caramel, capsanthin, beetroot, anthocyanins, bromothymol blue and green; in fact, of these colorants, only caramel has been found by the FDA to be safe for use in cosmetics.²⁰ Also imagine no longer developing hair dyes to sell to consumers, or banning all but two UV filters from sun product formulations.

Consider further: Is it possible to formulate cosmetics that consumers will buy that do not contain ingredients derived from an ethylene oxide reaction? Further, the foundation’s report missed all the other ingredients made from ethylene oxide, such as phenoxyethanol, glycol stearate, etc. Imagine what products would smell like without fragrances to mask odors; or, better yet, imagine the reaction from marketing when you present these newly formulated products.

This author believes that chief executives of major cosmetic companies should step forward to publicly comment on the safety of their products, to report how few if any minor injuries were ever attributed to the proper use of their products, and to describe the extensive testing performed on their products to ensure consumer safety. This would denounce to the public the unnecessary alarm being caused by activist groups that publish information based on fraudulent science, and educate the representatives introducing bills to the US Congress based on bad information. R&D professionals in the personal care industry are urged to send letters to their representative(s) in Congress to make the truth known.

As a final comment, this author’s greatest disappointment is with the David Suzuki Foundation in that it has bought into such junk science after 20 years of being a reputable NGO. Perhaps the group simply does not grasp the fact that cosmetics are among the safest consumer products, that they are tested for safety, and that if all the ingredients the group recommends prohibiting were removed from products, consumers’ lives would look less attractive, smell worse and be less comfortable—and yet be no safer—than they are currently.

References

Send e-mail to [email protected].

1. ‘Dirty Dozen’ Cosmetic Chemicals to Avoid, David Suzuki Foundation, www.davidsuzuki.org/issues/health/science/toxics/dirty-dozen-cosmetic-chemicals/index.php  
2. 182.3169 BHA, FDA Code of Federal Regulations (CFR) Title 21: Food and Drugs, www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm
3. 172.115 BHT, FDA Code of Federal Regulations (CFR) Title 21: Food and Drugs, www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm  
4. CIR Report 21/11/2007, www.cir-safety.org/staff_files/PublicationsListDec2009.pdf
5. CIR Report 1/28/2009, www.cir-safety.org/staff_files/PublicationsListDec2009.pdf
6. JACT 2(7) 183-235 (1983), www.cir-safety.org/staff_files/PublicationsListDec2009.pdf  
7. JACT 4(3) 267-303 (1985), available at www.cir-safety.org/staff_files/PublicationsListDec2009.pdf
8. EM Jackson, Subungual penetration of dibutyl phthalate in human finger nails, Skin Pharmacol Physiol 21 10–14 (2008)
9. JGM Winkelman et al, Kinetics and chemical equilibrium of the hydration of formaldehyde, Chemical Engineering Science 57 4067–4076 (2002)
10. CIR website, www.cir-safety.org/staff_files/PublicationsListDec2009.pdf  
11. Ingredients, International Fragrance Association website, www.ifraorg.org/public/index_ps/parentid/1/childid/15/leafid/111  
12. JACT 4(3) 267–303 (1985), CIR website, www.cir-safety.org/staff_files/PublicationsListDec2009.pdf  
13. Scientific Committee on Consumer Products (SCCP) Opinion on Phthalates in Cosmetic Products, https://ec.europa.eu/health/ph_risk/committees/04_sccp/docs/sccp_o_106.pdf
14. RIFM news release, RIFM human health scientist publishes article on vehicle effects on allyl ester irritation in the international journal of toxicology, www.rifm.org/press/press_detail.asp?id=16  
15. IJT 27 suppl. 4, 1–82 (2008), CIR website, available at www.cir-safety.org/staff_files/PublicationsListDec2009.pdf  
16. Parabens, FDA website, www.fda.gov/Cosmetics/ProductandIngredientSafety/ SelectedCosmeticIngredients/ucm128042.htm 
17. 1,4-Dioxane, FDA website, www.fda.gov/Cosmetics/ProductandIngredientSafety/ PotentialContaminants/ucm101566.htm 
18. Annex II number 904, p 46, EU website, http://eurlex.europa.eu/LexUriServ/LexUriServ.douri=CONSLEG:1976L0768:20080424:en:PDF 
19. https://www.ec.gc.ca/substance/ese/challenge/batch2/batch2_siloxanes_rms_en.pdf 
20. Color Additives Permitted for Use in Cosmetics, FDA website, www.fda.gov/Cosmetics/GuidanceComplianceRegulatoryInformation/VoluntaryCosmeticsRegistrationProgramVCRP/OnlineRegistration/ucm109084.htm (All websites accessed on Aug 24, 2010)