Superwash vs Alpaca wool: environmental & health impacts

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].

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 natural 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 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.

Feature	Superwash Wool (e.g., Merino)	Untreated Alpaca Wool	Consequences
Common Fibers Treated	Merino wool, sheep wool blends	Not applicable	Primarily targets high-scale fibers
Chemical Treatment	Chlorine oxidation, resin coating	None	Toxic by-products, microplastics
Water Use	Very high	Low	Contributes to wastewater load
Environmental Impact	Very high	Low	AOX, microplastic pollution
Biodegradability	Low (due to resin coating)	100%	Resin persists in soil/ocean
Natural Odor Control	Diminished	Strong	Resin disrupts natural properties

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.

Jordy Munarriz

Environmental Engineer with a master’s degree in renewable energy and a specialization in sustainability. A passionate traveler and advocate for responsible tourism, he captures the essence of exploration through storytelling, inspiring others to connect with nature in a conscious and meaningful way.