An activewear brand came to us recently with a question we hope to see more activewear founders asking: can you help me trace the chemistry in my supply chain?

We love this question: Most "clean" activewear stops at fibre choice. Swap synthetics for wool, tell the plastic story, done. But the fibre is only where a garment starts.

The chemistry that ends up against your skin for a two-hour run lives in the washes, the dyes and the finishes, and wool goes through plenty of them.

They asked our team to help them uncover:

1. What are the most common chemicals in a wool supply chain?
2. What should they be avoiding?
3. What claims should they be aspiring to make, if they want to ensure they're delivering a healthier experience for runners, beyond a simple certification or "low toxicity" label?

To start, let's talk about what wool on its own.

Wool regulates temperature by absorbing moisture vapour and releasing heat. It binds odour molecules rather than just holding sweat. Untreated, it offers meaningful UV protection. It doesn't melt onto skin. At the end of its life it breaks down in soil in months rather than shedding microplastics. No chemicals required.

But between the sheep and the finished garment, wool passes through six stages, and chemistry can hide in almost every one.

• On the farm. Sheep might be treated for lice and scab with dips and pour-ons, often organophosphates or pyrethroids.

• Grading and sale. Baled wool can be treated with storage preservatives, and certified wool can be mixed with uncertified wool if nobody is tracking it.

• Scouring and carbonising. Raw wool is washed in hot water and detergent to strip lanolin and dirt, historically with alkylphenol ethoxylates (APEOs). Wool with lots of plant matter is then often treated with sulfuric acid to burn out burrs and seeds.

• Yarn and fabric. Fibre can be chlorinated to strip its natural scales, then coated in a synthetic polyamide resin so it can be machine-washed without felting. Mothproofing insecticides are sometimes added here too.

• Dyeing and finishing. The most chemically intense stage. Dyes and their auxiliaries, bleaches, softeners, easy-care resins, water repellents and antimicrobial treatments can all enter here.

• Cut and sew. Usually the least chemically intensive phase. However, Thread, elastic, printed labels, logos, zips and snaps may each bring their own chemistry.

Steal our framework: we recommended chemicals for avoidance based on exposure, hazard, residue and necessity.

1. Does it reach the body? (exposure)
A chemical that never leaves the factory poses little risk to the wearer. Activewear raises the stakes because it creates the conditions that move chemicals out of fabric and onto skin: sweat, heat, friction, a close fit and hours of wear. A running cap sits against the forehead for an entire run.

2. What can it do? (hazard)
Chemicals in textiles tend to fall into a few types of harm:

• Skin irritation and allergy: reactions on contact, which can become lifelong sensitivities (formaldehyde, nickel)

• Cancer risk: compounds classified as carcinogens (the amines released by certain azo dyes)

• Hormone disruption: substances that interfere with the body's hormone signals (PFAS, APEOs, some phthalates)

• Persistence: chemicals that don't break down and build up in bodies and ecosystems (PFAS, chlorine by-products, some chelants)

• Harm to water and wildlife: toxic to fish and aquatic life, eventually reaching people through water and food (APEOs, antimicrobials, insecticides)
  
  

3. Does it stay in the garment? (residue)
Some chemicals are mostly washed out during production; their impact lands on waterways and factory workers. Others are designed to stay on the fabric for its whole life. Finishes, coatings, dyes and trims are made to last, which makes them the main risk to the wearer.

4. Does wool need it? (necessity)
Many finishes do a job merino already does: repelling light moisture, resisting odour, regulating temperature. If a chemical adds risk without adding performance, removing it costs nothing.

The result: a chemical that reaches the skin, has a serious hazard, stays in the garment and does a job wool already does is the clearest case for removal.

Curious about what's in your supply chain? We'd love to talk! hello@ableecosystems.com.