Siloxanes

How am I exposed to siloxanes?

Exposure to siloxanes is common because of their widespread use in industry and across sectors, resulting in their presence in consumer and professional products including cosmetics, personal care products, dry cleaning processes, cookware, waxes, cleaners, and more.^{1, 4}

People are exposed to siloxanes from multiple sources, due in part to their volatility. Major exposure pathways include cosmetics and personal care products as well as contaminated indoor air and dust.^{4, 7, 8} Major exposure scenarios involve:

• Beauty and personal care products: Siloxanes are found in cosmetics including primer, lipstick, mascara, and foundation, and in personal care products like moisturizers, antiperspirants, sunscreen, shampoos, conditioners, and body wash.⁹ Applications include use as emollients and spreading agents.⁸ People are primarily exposed via inhalation and skin absorption during application and use of these products.^{8, 10} Furthermore, siloxanes are known to be used in haircare products marketed towards women of color, which may lead to disproportionate exposure.¹¹
• Indoor air and dust: Siloxanes are contaminants of indoor air and dust because of their presence in consumer products and other materials and substances, leading to inhalation, ingestion, and dermal exposure.^{5, 7}

Why should I be concerned?

Siloxanes are associated with multiple adverse health effects.¹ The cyclic volatile methyl siloxanes (cVMS) commonly referred to as D4, D5, and D6 are linked to cancer, developmental and reproductive toxicity, endocrine disruption, and liver toxicity.^{1, 2} cVMS may be present in products containing PDMS or dimethicone.^{3, 6}

Due to concerns around their persistence, tendency to bioaccumulate, and toxicity, the European Union has adopted a broad restriction on certain cyclic siloxanes, including restricting their use in personal care products and cosmetics.^{12, 13} However, in the U.S., siloxanes continue to be produced at high volumes, and global production is estimated to be over 10 million tons annually.^{3, 14} The U.S. Environmental Protection Agency (EPA) reported 2019 domestic production volume for D4, D5, and D6 as between 250 to 500 million pounds, 100 to 250 million pounds, and 1 to 10 million pounds, respectively.

Concerns over siloxanes are not limited to human health hazards. When cosmetics and personal care products containing siloxanes are washed off, they contribute to environmental contamination.¹⁵ A primary concern is related to the chemical stability and persistence of these chemicals in the environment and their ability to bioaccumulate.¹³ The European Union’s chemical regulatory agency, ECHA, has designated multiple siloxanes as substances of very high concern, including VMS compounds L3 and L4 due to their designations as very persistent and very bioaccumulative substances.^{16, 17}

As restrictions grow on the use of hazardous per- and polyfluoroalkyl substances (PFAS), siloxanes have been used as replacements in applications like textile treatments and in non-stick cookware.^{18, 19} This results in regrettable substitutions where one class of hazardous chemicals is replaced with another, rather than with safer alternatives.²⁰

Which companies manufacture siloxanes?

According to U.S. EPA Chemical Reporting Data from 2020, manufacturers of common siloxanes included, but may not be limited to (listed alphabetically): Avantor Inc, K&M Holdings Group LLC, Momentive Performance Materials, The Dow Chemical Co, and Troy Corporation.

How can I reduce my exposure?

• Push for safer products and policies: The most effective way to reduce exposure for everyone is to support policies and market actions that phase out harmful siloxanes and replace them with safer alternatives. Tell your favorite brands, retailers, and policymakers that you want products free of siloxanes — and that substitutes must be proven safer.
• Choose products without siloxanes or silicones: Look for “silicone-free” labels on cosmetics, personal care items, and household products. For household products like cookware, consider safer alternatives such as stainless steel. For cosmetics, avoid products listing these ingredients^{21, 22}:
  • Dimethicone
  • Polydimethylsiloxane (PDMS)
  • Cyclomethicone
  • Any other uses of the terms “siloxane,” “silicone,” or “methicone”
• Improve indoor air quality: Use ventilation, exhaust/intake fans, and air filters to potentially reduce indoor air pollution, especially if using siloxane- or silicone-containing cosmetics or cookware products.²³

What’s the solution?

It is impossible for us to shop our way out of this problem. And we shouldn’t have to. When you walk into a store, you should be able to trust that the products on store shelves are safe.

Companies shouldn’t sell products with dangerous chemicals or plastics — especially as scientists continue to learn more about the “silent epidemic” caused by the cumulative impact of all the toxic chemicals to which we are regularly exposed. And our state and federal governments shouldn’t allow chemicals on the market until they’re proven safe.

The only way to protect everyone from toxic chemicals like siloxanes is to change policies at government and corporate levels to make sure that safer solutions are the norm. 

We’re fighting every day to protect you and your loved ones from toxic chemicals. To join our fight, please consider making a donation, taking action with us, or signing up for our email list.