Superwash vs Alpaca Wool:
 Environmental & Health Impacts

Reading time: 6 minutes
By Jordy Munarriz

Superwash wool refers to wool fibers that have undergone chemical treatments or coatings to make them machine-washable and shrink-resistant. This process, widely used in mass-market merino wool products, aims to eliminate the felting and shrinkage that naturally occur when untreated wool is exposed to agitation and heat.

Marketed as “easy care”, superwash merino wool is popular in athletic wear, children’s garments, and socks due to its low-maintenance appeal. But behind that convenience is a multi-step industrial process that transforms a natural fiber into something far from its original form.

How Superwash Wool Is Made

The superwash process typically involves two main steps, which may be used separately or combined:

Chlorination (Chemical Etching)

This step involves treating the wool with chlorine-based compounds such as sodium hypochlorite or gaseous chlorine. This chemical bath oxidizes and removes the natural outer layer of wool—the cuticle scales—which are responsible for felting.

• Chlorination produces adsorbable organic halides (AOX), a class of toxic by-products that are persistent in aquatic ecosystems and potentially carcinogenic to humans [1,2,3].
• Chlorine gas is a hazardous chemical with significant occupational and environmental risks [3,4].

Polymer Coating (Resin Layer)

After chlorination, the fiber is coated with a synthetic polymer—commonly Hercosett 125 (a polyamide-epichlorohydrin resin) [3]. This layer prevents the fibers from interlocking, making the wool smoother and resistant to felting during washing.

• Environmental and health concerns: Hercosett resin contains epichlorohydrin, a known mutagen and probable human carcinogen. Numerous studies have shown that epichlorohydrin is a potent mutagen, capable of inducing chromosomal aberrations and DNA mutations in exposed animal and human cells, as well as DNA damage in bacteria and yeast [5,6].
• Toxicological evidence: Epichlorohydrin induces tumors in animal models and has shown carcinogenic effects in experimentally exposed tissues. In humans, occupational exposure is associated with increased chromosomal abnormalities and possible cancer risks, though epidemiological evidence remains limited [5,6,7].

Moreover, the resin coating is not biodegradable, contributing to microplastic pollution when garments shed fibers during washing and wear [8].

6. Upgrade Your Hygiene and Cleaning Habits

Small changes to your personal care and cleaning routines can have a big impact:

• Switch to bamboo* toothbrushes: Look for ones with compostable bristles and packaging.
• Choose steel razors: A durable, waste-free alternative to disposable razors.
• Use natural options: Biodegradable shampoos, soaps, and detergents are better for the planet.
• Use menstrual cups and fabric sanitary towels: They take a little getting used to, but you won’t go back when you do!
• Clean with vinegar and baking soda: These simple ingredients work wonders around the house and are free of harmful chemicals [8].

* When choosing products made from bamboo, try to ensure the bamboo comes from sustainable sources.

7. Embrace Nature and DIY Solutions 

Spending time outdoors and trying DIY solutions are both fun and sustainable:

• Grow your own vegetables: Even a small herb garden on a windowsill can make a difference.
• Start composting: Turn food scraps into nutrient-rich compost for your garden. No garden? Check if your city collects food waste.
• Connect with nature: Spending time outside reduces stress and reminds us why protecting the planet matters.
• Join community initiatives: Participate in clean-ups or tree-planting events.

At Arms of Andes we make our gear from 100% Royal Alpaca Wool of 18-18.5 microns.

MIDWEIGHT HOODIEWomen's Alpaca Wool Joggers 300 Lightweight

Environmental and Structural Impacts of Superwash Wool

While Superwash wool offers convenience, the process fundamentally alters both the performance and environmental profile of the fiber.

Environmental Impact

• Chlorinated wastewater: Superwash treatments often involve chlorine, generating AOX (adsorbable organic halides)—toxic, persistent pollutants harmful to aquatic life and capable of bioaccumulating in food chains [2,3,9].
• Plastic resin coatings: The commonly used Hercosett resin, derived from petrochemicals, is non-biodegradable. With wear and washing, it sheds microplastics into water and soil [3].
• High resource consumption: The process requires significant water, energy, and chemicals—not only for chlorination but also for repeated rinsing and polymer application [9].

Aesthetic & Structural Changes

• Loss of insulation and thermoregulation: The smooth resin surface reduces the fiber’s ability to trap air, undermining wool’s natural thermal regulation [9].
• Reduced moisture-wicking: The polymer coating impairs breathability, limiting the fiber’s ability to manage humidity and skin comfort [10,11].
• Artificial, glossy appearance: Superwashed wool loses its natural matte finish and develops a plastic-like sheen, distancing it from its organic origin [12,13].
• Reduced elasticity: With repeated laundering, Superwash wool may stretch out or lose shape, especially in fine knits [12].
• Altered tactile experience: The coating creates a slick surface that resembles synthetic fabrics, reducing wool’s softness and friction-based warmth [13,14].
• Lower biodegradability: The synthetic resin prevents natural decomposition, disqualifying the fiber from compostability certifications [14,15].
• Altered tactile and skin interaction: The coated fiber behaves less like natural wool, affecting how it feels on the skin and its ability to regulate microclimate and odor [16].

Why the Industry Relies on It

The commercial success of Superwash wool stems from its ability to meet modern consumer expectations—ease of care, machine-washability, and durability. Traditionally, wool required special handling due to its tendency to shrink and felt when agitated in water. This discouraged buyers and limited its use in mass-market apparel. The Superwash process addressed these limitations through chemical and polymer treatments that alter the fiber surface.

Key industry advantages include:

• Shrink-Resistant Wool: The removal or smoothing of surface scales and subsequent polymer coating prevent felting, making garments safe for machine washing and drying [16].
• Color-Fast Fabrics: Treated wool absorbs dyes more uniformly and intensely, increasing color saturation and reducing fading in industrial laundering [17].
• High Volume Output: The process aligns with large-scale industrial systems, allowing manufacturers to integrate wool into fast fashion pipelines without sacrificing efficiency [18].

These transformations highlight the trade-offs involved: a natural, regenerative fiber is chemically altered to fit industrial systems—at the cost of its unique, sustainable qualities.

The Arms of Andes Commitment to Plastic-free Alpaca Wool

At Arms of Andes, we use 100% Alpaca Wool sourced directly from the Andes of Peru. Unlike sheep wool, alpaca fibers are naturally lanolin-free, have fewer surface scales, and are less prone to felting. This means we don’t need chemical treatments to achieve durability or softness.

Natural Structure Reduces Felting

Alpaca wool has a smooth surface with lower scale height, which reduces friction and prevents fibers from locking during washing. Unlike sheep wool, it doesn’t require chlorine treatment or plastic coatings to remain usable.

Natural Performance Intact

Alpaca wool retains: High thermal insulation, breathability. antibacterial and odor resistance, and hypoallergenic softness.

When left untreated, alpaca wool performs as nature intended—without sacrificing function.

100% Biodegradable: No Plastic, No Superwash

All Arms of Andes garments are fully biodegradable. By avoiding Hercosett resins, we ensure our products can return to the earth after their lifecycle, aligning with circular economy goals.

How to Care for Natural Alpaca Wool

No Superwash? No problem. Here’s how to care for your natural alpaca wool garments:

• Air Out: Between wears, hang in a dry, shaded area to refresh.
• Cold Wash: Hand wash or machine wash in cold water on wool cycle.
• Mild Detergent: Use neutral pH detergent free of enzymes and bleach.
• Dry Flat: Reshape while damp and dry flat away from heat.
• Avoid Agitation: Never tumble dry, wring, or expose to hot water.

With these simple steps, your alpaca clothing will last for years—even with frequent use outdoors.

FAQ

• Is Superwash Wool Toxic?
  Residues of chlorine and plastic resin may cause irritation or long-term harm, especially for those with sensitive skin or allergies.
  
• Does Superwash Shed Microplastics?
  Yes. Polymer coatings degrade with use and laundering, releasing particles into the environment.
• Is Alpaca Wool Harder to Care For?
  No. When treated gently, it resists odor and wear better than many other fibers. Cold washing and air drying are usually sufficient.
• Does Superwash Make Wool Better for Outdoor Use?
  Not necessarily. Untreated alpaca outperforms chemically altered fibers in insulation, breathability, and environmental safety.

References:
[1] Rodie, J. B. (2016). Quality fabric of the month: Sustainable machine-washable wool. Textile World. https://www.textileworld.com/textile-world/quality-fabric-of-the-month/2016/02/quality-fabric-of-the-month-sustainable-machine-washable-wool/
[2] Browne, M. A., Crump, P., Niven, S. J., Teuten, E., Tonkin, A., Galloway, T., & Thompson, R. (2011). Accumulation of microplastic on shorelines worldwide: Sources and sinks. Environmental Science & Technology, 45(21), 9175–9179. https://doi.org/10.1021/es201811s
[3] Hassan, M. M., & Carr, C. M. (2019). A review of the sustainable methods in imparting shrink resistance to wool fabrics. Journal of Advanced Research, 18, 39–60. https://doi.org/10.1016/j.jare.2019.01.014
[4] Agency for Toxic Substances and Disease Registry. (2010). Toxicological profile for chlorine. U.S. Department of Health and Human Services, Public Health Service.
[5] National Institute for Occupational Safety and Health. (1978). Current Intelligence Bulletin 30: Epichlorohydrin (DHHS Publication No. 79-105). U.S. Department of Health and Human Services.
[6] Cherrie, J. W., Gorman Ng, M., Lamb, J., Shafrir, A., van Tongeren, M., Mistry, R., Sobey, M., Corden, C., Rushton, L., Hutchings, S., Searl, A., Warwick, O., Bouhier, M.-H., Kaupinnen, T., Heikkila, P., Kromhout, H., & Levy, L. (2011). Health, socio-economic and environmental aspects of possible amendments to the EU Directive on the protection of workers from the risks related to exposure to carcinogens and mutagens at work: 1-Chloro-2,3-epoxypropane (epichlorohydrin) (IOM Research Project: P937/25). Institute of Occupational Medicine (IOM).
[7] World Health Organization. (1984). Environmental health criteria 33: Epichlorohydrin. International Programme on Chemical Safety.
[8] Napper, I. E., & Thompson, R. C. (2016). Release of synthetic microplastic fibres from domestic washing machines: Effects of fabric type and washing conditions. Marine Pollution Bulletin, 112(1–2), 39–45. https://doi.org/10.1016/j.marpolbul.2016.09.025
[9] Savant DV, Abdul-Rahman R, Ranade DR. Anaerobic degradation of adsorbable organic halides (AOX) from pulp and paper industry wastewater. Bioresour Technol. 2006 Jun;97(9):1092-104. doi: 10.1016/j.biortech.2004.12.013. Epub 2005 Mar 19. PMID: 16551531.
[10] Napper, I. E., & Thompson, R. C. (2016). Release of synthetic microplastic plastic fibres from domestic washing machines: Effects of fabric type and washing conditions. Marine Pollution Bulletin, 112(1-2), 39-45.
[11] De la Maza, A., García Dominguez, J. J., & Parra, J. L. (1981). Interacción de resinas-agentes de superficie y su aplicación en el antiencojimiento de la lana. Instituto de Tecnología Química y Textil, C.S.I.C.
[12] Hao, Y., Wang, H., Tian, D., Zhang, W., & Shi, B. (2025). Scalable production of robust, moisture-wicking, and breathable superfine mycelium fiber/waterborne polyurethane leather-like textile via direct casting and oven-drying. Industrial Crops and Products, 226, 120632. https://doi.org/10.1016/j.indcrop.2025.120632
[13] Holt, R. R. D. (1975). Introduction to superwash wool. Journal of the Society of Dyers and Colourists, 91(2), 38–44.
[14] European Commission. (2020). Full recyclable food package with enhanced gas barrier properties and new functionalities by the use of high-performance coatings (Periodic Reporting for period 2 - REFUCOAT). https://doi.org/10.3030/745791
[15] Farm Fiber Knits. (2024). What is the superwash process and what does it do to wool? Farm Fiber Knits. https://farmfiberknits.com/what-is-the-superwash-process-and-what-does-it-do-to-wool/
[16] Ellen MacArthur Foundation. (2017). A new textiles economy: Redesigning fashion’s future. Ellen MacArthur Foundation. Retrieved July 9, 2025, from https://www.ellenmacarthurfoundation.org/a-new-textiles-economy
[17] Buratti, C., Barbanera, M., Testarmata, F., & Fantozzi, F. (2015). Life cycle assessment of organic waste management strategies: An Italian case study. Journal of Cleaner Production, 89, 125–136. https://doi.org/10.1016/j.jclepro.2014.11.012
[18] Shen, L. (2014). Life cycle assessment of wool textile products. International Wool Textile Organisation (IWTO).