A Detailed Review of Nylon Toxicity

In terms of toxicity, nylon/polyamide textiles can be made with bisphenols, toxic dyes as well as contain potential toxic additives like PFAS, flame retardants, and more described in the article.

I will look at the toxicity of nylon in other applications as well.

Conventional nylon/polyamide is a plastic that is fairly hard on the environment in a number of ways.

Though recycled nylon, biodegradable nylon, and bio-based nylon all contribute to more environmentally friendly outcomes.

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Overview: Potential Chemicals of Concern in Nylon

• BPA or other Bisphenols – BPS may be used as an ingredient in dye-fixing agents for polyamide textiles (source). Also, there is a small chance that epoxide cross-linking agents are used and those could contain bisphenols.
• PFAS – Nylon textiles certainly can be treated with PFAS to be stain-resistant or, water-resistant and wicking.
• Dyes, treatments, and additives – Including the toxic azo dyes or dyes containing Chromium.
• Metals and nanometals – A number of treatments in nylon fabric can contain metals or nanometals like Chromium, Antimony, Aluminum, Copper, Zinc, Titanium Dioxide, and more.
• Flame retardants – Toxic flame retardants can be used on nylon but only in specific applications like tents (though the trend now is moving away from flame retardant use, see this article for safer tents), curtains, car seats, and flame-resistant clothing.
• Antimicrobials – Nanometals or toxic halogenated antimicrobials can be used.
• Caprolactam – Can be released from nylon cooking utensils, due to high heat and acidity.
• Microplastics – Nylon breaks down into microplastics if it’s not one of the biodegradable types talked about in a later section.

Phthalates are not found in nylon – none of the specified phthalates or elements were reportedly used in the manufacture of any of the undyed polyamide fiber or fabric. (source)

Action Steps:

• Look for PFAS-free and flame-retardant-free textiles
• Avoid nylon marketed as antimicrobial (unless they use a natural non-toxic antimicrobial)
• Avoid toxic azo dyes and dyes that use Chromium
• Consider recycled nylon if environmental concerns are primary
• Consider biodegradable nylon to reduce its post-consumer impact
• Consider bio-based nylon to reduce reliance on fossil fuels
• Use a Guppyfriend to catch microplastics in the wash and prevent them from entering the water

Phthalates are not found in nylon – none of the specified phthalates or elements were reportedly used in the manufacture of any of the undyed polyamide fiber or fabric. (source)

Is Nylon Toxic?

Nylon Itself Can be Non-Toxic

Pure nylon fabric or molded nylon products (like kitchen utensils) are considered low-VOC materials under regular conditions. Once polymerized, nylon is relatively inert and does not off-gas significant amounts of VOCs. However, residual monomers or additives (like dyes and treatments) can contribute to higher toxicity, and it can contain bisphenols.

One of the primary VOCs associated with nylon, especially Nylon 6, is caprolactam. It is a monomer used in the production of Nylon 6 and can be released during both manufacturing and further processing. Caprolactam is considered a volatile organic compound, and although its levels in finished products like textiles and cooking utensils are typically low, it can still off-gas to some extent, says Dr. Mudgal, toxicologist.

Potential Toxic Additives in Nylon Textiles

Potential toxic additives to nylon textiles include azo dyes, dyes with Chromium, Aluminum additives, Antimony, nanoparticles, ethoxylated chemicals (which can be contaminated with 1,4 dioxane), bisphenols, halogenated antimicrobials, and potential treatments like PFAS and flame retardants. None of these surface treatments are unique to nylon textiles specifically, and they are not added to all nylon.

Recycled nylon made from carpet and industrial waste could contain additional flame retardants (potentially more toxic ones), PFAS, and antimicrobials.

Nylon in Cooking

From nylon cooking utensils, caprolactam can be released.

Caprolactam leaching from these products is considered minimal and safe by regulatory agencies like the FDA and Health Canada.

IARC also determined that caprolactam is probably not carcinogenic to humans (Group 4), says Dr. Mudgal, toxicologist.

I certainly would not use recycled plastic cooking utensils, as the potential for contamination with chemicals of concern could be high (depending on the source of the nylon).

Nylon in Cosmetics

Nylon polymers are used in cosmetics primarily as bulking and opacifying agents.

It was determined that the polymers are not likely to penetrate the skin. The residual monomers that can be present were not present at a sufficient level to cause any reactions in test subjects. (Source)

The nylon ingredients (nylon-6, nylon-11, nylon-12, nylon 6/12, nylon-66, nylon-611, nylon-10/10, and nylon-12/6/66 copolymers) are not restricted from use in any way under the rules governing cosmetic products in the European Union, says Dr. Mudgal.

Nylon in Food Packaging & Medical Uses

Nylon-6, nylon-11, nylon-12, nylon 6/12, and nylon-66 have been approved by the FDA as indirect food additives used for food contact surfaces and are identified as GRAS (Generally Recognized as Safe) under sections 21 CFR 177.1500 and 21 CFR 177.1200 of the FDA.

Nylon-6 and nylon-66 are used in non-absorbable surgical sutures, which are FDA-approved medical devices under 21 CFR 878.5020 of the FDA.

Environmental Impact

• Nylon manufacturing creates nitrous oxide, a greenhouse gas 310 times more potent than carbon dioxide. (source)
• The creation of nylon is energy-intensive. (source)
• Conventional nylon is not biodegradable (more on that in a below section). (source)
• Nylon does create microplastic pollution if not a biodegradable type. (source)
• Most nylon is made from petrochemicals. (source)
• The manufacturing process generally requires significant water usage. (source)
• Effluents from the production of nylon textiles can contain chemicals that, if not treated properly, may harm the environment. (source)

Allergic and Chemical Sensitivity Reactions

Some people experience allergic reactions or skin irritation from nylon clothing (source). 

It has a CLP classification Category 2 eye irritant (Nylon 6) and skin irritant (Nylon 6 and Nylon 66) meaning that although it is capable of causing skin and eye irritation, the effects will be reversible and this will be a non-corrosive effect, says Dr. Mudgal, Toxicologist.

Also, some chemically sensitive people are reactive to some or all nylon fabrics. This can be a reaction to the dyes and additives or to the nylon itself.

In a survey of highly chemically sensitive people, around one-third reacted to all nylon, one-third to only some nylon, and around one-third did not react to nylon.

Which Chemicals are Used in Treatments and Dyes of Nylon Fabric

1. Scouring:
   • Sodium carbonate (soda ash)
   • Detergents or surfactants
   • Trisodium phosphate (TSP)
   • Ammonia
   • Enzymes
2. Bleaching:
   • Sodium chlorite and dechlorinate
3. Dyeing:
   • Acid dyes (common), usually contain metals like Chromium
   • Disperse dyes with decamethylcyclopentasiloxane
   • Azo dyes (toxic)
   • Anthraquinone dyes (potentially toxic)
   • Reactive dyes like Stanalan and Eriofast
   • Carriers or accelerants (to help dye penetration), common carriers include: Phenolic substance: o & p – phenylphenol, Primary amines, Hydrocarbons: Diphenyl, Esters: Di-methyl ester of terephthalic acid, Acids: Benzoic acid and salicylic acid, Amides: N-Alkyl phthalamide derivatives, Alcohols, ketones, Etheres, Nitriles, Carbamates: o-octyl carbamate, pH adjusters (acetic acid, formic acid).
4. Soaping (after dyeing):
   • Mild detergents
   • Maleic-acrylic co-polymer
5. Fixing:
   • Tannic acid with a form of antimony
   • Cationic fixing agents
   • Resin-based fixatives
6. Finishing:
   • Softeners (silicone-based, cationic, can contain ethoxylated chemicals)
   • Water repellents (fluorocarbons, silicones)
   • Flame retardants added to camping gear, curtains, or specialty flame-resistant clothing
   • Anti-static agents like quaternary ammonium or amphoteric surfactants
   • Anti-microbials, including zinc, copper, titanium dioxide, and silver-based formulas (including nanosilver), and halogenated chemicals (toxic)

Additional chemicals potentially used in nylon:

• Optical brighteners containing sulphonate groups.
• Stabilizers like acetic acid early in the process.
• UV stabilizers like HALS (hindered amine light stabilizers), benzophenone, or triazines can prevent UV degradation and discoloration.
• Fiber-strengthening additives like carbon nanotubes, graphene, or nano silica can improve the mechanical properties of nylon fibers.
• Hygroscopic materials like silica, calcium chloride, or alumina.
• Nucleating agents like talc, calcium carbonate, or kaolin.
• Thermal stabilizers like check Antioxidants: Hindered phenolic compounds (e.g., Irganox 1010) that prevent thermal degradation and discoloration. Phosphites: Compounds like tris(2,4-di-tert-butylphenyl) phosphite that inhibit thermal degradation and oxidation. Lactones: Compounds like 2-hydroxy-4-n-octoxybenzophenone that absorb UV light and prevent thermal degradation.
• Lubricants like silicones or fatty acid amides can reduce fiber friction, preventing breakage and improving spinning efficiency.
• Cross-linking agents like isocyanates or epoxides can improve the mechanical properties of nylon, reducing the likelihood of breakage and defects. Epoxides could potentially introduce bisphenols.

Many products in this list of chemical types do or can contain ethoxylated chemicals which can be contaminated with 1,4 dioxane.

The sources for all these chemicals used in the production of nylon textiles are at the bottom of the article.

What is Nylon?

Nylon or polyamide (PA) is a plastic that includes PA6, PA66, PA610, PA1010, PA11, and more.

• PA6 (Nylon 6) and PA66 (Nylon 6,6) are the most commonly used types, especially in textiles. (source)
• Nylon-6,12 and its copolymers are also used as engineering resins for specialty applications and in the manufacture of toothbrush bristles and fishing line (source).
• Nylon-4 is also a synthetic plastic that is petroleum-based, though it is considered technically biodegradable.
• Most nylon is made from crude oil or gas. However bio-based nylon can be made from entirely renewable sources.

Better Nylons/Polyamides

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1. Recycled Nylon

Brands

Clothing brands such as, Swedish Stockings, Berlook, Outerknown, and Aquafil use recycled nylon in their products.

Carpet brands Sedna (UK) and Dura Contract (EU) use recycled nylon.

You can find more brands on the Sensil and ECONYL websites.

Sources for Recycled Nylon

Recycled nylon comes from a variety of sources, including fiber left over from fishing nets (including abandoned fishing nets in the ocean), fabric scraps, carpet flooring, and industrial waste plastic.

Recycled or “regenerated” nylon uses nylon that already exists as pre-consumer and/or post-consumer waste products.

Companies Making Recycled Nylon

Recycled nylon fabric brands include Sensil EcoCare and ECONYL, and they are better for the planet. 

ECONYL claims:

• For every 10,000 tons of raw material used to produce ECONYL nylon, we save 70,000 barrels of crude oil.
• Reduce the global warming impact of nylon by up to 90% when compared with traditional nylon.

Sensil EcoCare claims:

• Reduction of up to 98%, or 6.2 tons of CO2 equivalent emissions per 1 ton of yarn.
• Energy savings of up to 45 MWh/Ton in the upstream yarn manufacturing process.
• Water savings – up to 2.7 m3 /kg of yarn in the upstream yarn manufacturing process.

Concerns with Recycled Nylon

It is recyclable, but not biodegradable, and it still needs to be dyed in the same way as virgin nylon.

I would also expect that flame retardants and PFAS (and potentially antimicrobials) from the recycled carpet remain in the final product.

Pre-consumer fabric scraps and industrial waste plastic could also contain various chemicals of concern (like those outlined in the section on toxins in nylon textiles above, or those from e-waste – if that’s what they mean by industrial waste – explained here).

Sensil EcoCare is OEKO-Tex 100.

Recycled nylon fabric still produces microplastics. By using a Guppyfriend you can catch microplastics in the wash and prevent them from entering the water.

2. Biodegradable Nylon

Nylon-4

Nylon-4 is also a synthetic polyamide that is petroleum-based, though it is considered biodegradable.

The biodegradability of Nylon-4 film in seawater was approximately 80% within 25 days (source).

Straw Wheat Floss Picks are made with Nylon-4. (Most floss is made of conventional nylon).

CiCLO Nylon

There are also CiCLO-enhanced fibers that biodegrade if they end up in environments where biodegradation can occur naturally.

Microbes are attracted to the fibers and can mineralize them at rates comparable to natural fibers, such as wool.

It has OEKO-TEX ECO PASSPORT, certifying its ecologically responsible textile manufacturing and non-toxicity to marine life.

It’s also undergone biodegradation tests by The American Society for Testing and Materials (ASTM) to demonstrate the exact percentage and timeline in which the fiber breaks down in water, soil, landfill, and sewer sludge.

Definite Articles is a clothing brand that uses biodegradable nylon.

3. Biobased Nylon

There are ten different brands of bio-based nylon, most of them are partially bio-based and a few are 100% biobased.

Bio-based means instead of being made with petroleum products they use materials like castor oil, bio-gas, sugarcane from waste, and more.

• Enka Nylon BIO is 70% bio-based.
• SENSIL ByNature is made with biogas from waste, not clear what percentage is bio-based.
• Stanyl B-MB is available as a 100% bio-based.
• Bio Amni from Solvay is partially bio-based.
• EVO by Fulgar is 85% bio-based.
• Rilsan Polyamide 11 from Arkema is the original biobased polyamide made from 100% renewable castor oil.
• The Nymax BIO series from Avient uses up to 47% natural fillers derived from renewable sources like corn, straw, and wheat.
• VESTAMID Terra from Evonik PA 610 grade, with 62% bio-renewable content, the PA 1010 grade is entirely bio-renewable.
• EcoPaXX PA 410 contains 72% bio-based content derived from castor plants.
• TERRYL, a bio-based polyamide fiber brand by Cathay Biotech. Its bio-based content ranges from 45% to 100% renewable carbon content.
• Source https://www.bio-sourced.com/biobased-polyamides

Brands

Pangaia uses bio-based nylon in their activewear.

Nylon Uses:

• Clothing: From lingerie to outerwear, nylon is used in many types of clothing most notably sportswear.
• Hosiery: “Nylons” are indeed made of nylon.
• Outdoor Gear: Tents, backpacks, and other camping equipment are commonly made from nylon and treated with silicone or polyurethane (and in some cases PFAS and flame retardants as well). Umbrellas are also usually nylon.
• Home Textiles: Nylon fibers are the most common fiber used in carpeting, often treated with a number of chemicals from PFAS, to flame retardants and antimicrobials. When it comes to carpets, nylon fibers have higher off-gassing than other carpet fibers, generally speaking. It can be used for upholstery fabric as well.
• Commercial Textiles: Car seats, public seating, office chairs, and office furniture are often made from nylon.
• Industrial Uses: Ropes, and sometimes seatbelts are made of nylon. It can also form hard plastics to make screws, nuts, and bolts.
• Toothbrushes bristles and most floss. I review safer flosses here.
• Cooking utensils: Most of those black plastic cooking utensils you commonly see are nylon.
• Medical Devices: Due to its non-reactivity, nylon is sometimes used in medical equipment such as some surgical sutures, and parts of catheters, bandages, and hospital beds.
• Electronics: The coating on dishwasher racks is usually nylon (which is preferable to PVC), it’s also used in power tool housing, and parts of circuit boards.
• Packaging: Including food packaging.
• 3D printing

Corinne Segura is an InterNACHI-certified Healthy Homes Inspector with certifications in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes. You can book a consult here.

Sources

https://nctexchem.com/product/material/nylon/

https://crimsonpublishers.com/tteft/pdf/TTEFT.000655.pdf

http://www.koreafinechem.com/en/news/2021/06/09/scouring-and-bleaching-synthetic-fibres

https://www.shreechem.in/treatment-process-for-nylon

https://www.sciencedirect.com/science/article/abs/pii/S014139100900127X

https://www.sciencedirect.com/science/article/abs/pii/S0143720805000677#:~:text=Acid%20dyes%20are%20commonly%20used,fastness%20%5B1%5D%20are%20required.

https://www.sciencedirect.com/science/article/abs/pii/S0959652620333035

https://www.sciencedirect.com/science/article/abs/pii/S004565352302444X

https://www.sciencedirect.com/science/article/abs/pii/S0143720805000677#:~:text=Of%20the%20reactive%20dyes%20which,achieve%20outstanding%20wet%20fastness%20properties.

https://www.textiletoday.com.bd/carrier-dyeing-pros-and-cons

https://www.researchgate.net/figure/Dyeing-method-for-nylon-fabrics-with-Cr-complex-acid-dyes_fig2_283859036

Problems of nylon production and its solutions

https://www.sciencedirect.com/science/article/abs/pii/S0143720808000090#:~:text=In%20the%20latter%20context%2C%20as,1%5D%20in%20which%20the%20gallotannin

A Comprehensive Guide to different types of Dye Fixing Agents

https://www.yongjinbiotech.com/news/what-is-the-dye-fixing-agent-for-nylon-76868881.html

https://www.rossari.com/wp-content/uploads/2020/01/Nylon-1.pdf

Antimicrobial Textile & Fabric Additives

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8275915/