Wool

Wool is the fleece of sheep, spun into yarn and fabric. Chemically it's keratin — the same protein family as your own hair — with a natural crimp that traps air for insulation and a surface that manages moisture unusually well. Merino is simply wool from merino sheep, whose finer fibres feel soft enough to wear directly on skin.

Warmth, moisture management, and odour resistance — wool keeps you warm even when damp and needs washing far less often than synthetics. But the property this app cares most about is fire behaviour: wool is naturally slow to ignite, tends to self-extinguish, and chars rather than melting onto skin. That's why it has always been valued for blankets, bedding, and sleepwear, and why it can meet flammability expectations without chemical treatment.

Wool, 100% wool, merino, superfine or extrafine merino, lambswool, virgin wool, and the Woolmark logo (a certification mark for wool content and quality). "Superwash" or "machine-washable" wool has been treated so it won't felt in the wash — sometimes with a thin polymer coating, a processing detail rather than a known health concern. Cashmere, mohair, and alpaca are related animal fibres with similar properties.

Sweaters, coats, suits, socks, and base layers in the wardrobe; blankets, duvets, mattress toppers, and rugs around the home; merino sleepwear and sleep sacks for babies; and wool dryer balls in the laundry. It tends to cluster in exactly the places — beds and sleepwear — where flame-retardant chemistry would otherwise come up.

Mostly it doesn't — the fibre itself raises no chemical exposure concern. Three small contact routes exist: residual lanolin (the natural wool grease) can irritate a small number of sensitive people; coarse fibres can mechanically prickle skin, which is often mistaken for allergy; and wool carpets or stored woollens are sometimes treated with mothproofing insecticides, which is a treatment question, not a wool question.

No concerns from the fibre. Wool bedding and nursing-friendly merino layers are comfortable, temperature-regulating choices during pregnancy and postpartum. If you're preparing a nursery, wool blankets and sleep sacks are a calm way to get warmth without the added-flame-retardant question that hangs over some foam and synthetic products.

No documented concerns.

This is where wool earns its place. Children's sleepwear and bedding are the products where flame-retardant chemistry historically appeared — and wool's natural fire behaviour means wool versions don't need it. Merino sleep sacks and sleepwear are widely used for babies. Two notes: choose superfine merino for next-to-skin items, since coarse wool genuinely bothers some children, and follow normal safe-sleep guidance on bedding for infants regardless of material.

No specific signal. Wool bedding's temperature regulation is often appreciated by people whose sleep runs hot or cold, and lighter wool duvets can be easier to handle than heavy synthetic-filled ones. Purely practical considerations.

Wool's fire behaviour is settled materials science: high nitrogen and moisture content make it hard to ignite, and it chars and self-extinguishes rather than melting — which is why untreated wool meets flammability standards that some other fabrics need chemical help to pass. On skin, research suggests most "wool allergy" is mechanical irritation from coarse fibres; some studies have found superfine merino is tolerated well, even by many people with eczema. True lanolin allergy exists but appears uncommon.

Very low — wool sits firmly on the reassuring side of the ledger. The realistic issues are comfort-level: prickle from coarse fibres, and lanolin sensitivity in a small group. If wool reliably makes your skin itchy or flares eczema, that's worth respecting — choose superfine merino or switch to cotton, and mention persistent reactions to a health professional.

Wool usually is the alternative — to flame-retardant-treated sleepwear and bedding, to fragranced dryer sheets, and to synthetic fleece for warmth. If wool itself doesn't suit your skin, snug-fitting cotton sleepwear achieves the same no-added-flame-retardant outcome for children, and cotton or linen bedding covers the rest. For carpets, untreated wool or asking about mothproofing keeps that one treatment question in view.

The relevant question is how easy it is to choose, and the answer is easy — wool is clearly labelled, widely available, and a one-time purchase that lasts years. The trade-offs are price (merino costs more than synthetics) and care (some wool needs gentle or hand washing, though superwash versions are machine-washable).

If you use dryer sheets or liquid fabric softener, replace them with two or three wool dryer balls. It's a one-time purchase that softens laundry mechanically, removes a recurring source of added fragrance from every load, and pays for itself within months.

Wool is a buy-with-confidence material, and for sleepwear and bedding it quietly solves a problem: warmth and fire safety without added chemistry. Reach for merino next to skin, wool or snug cotton for children's sleepwear, dryer balls in the laundry — and if your skin protests, that's a comfort signal, not a safety one.

CPSC explains the children's sleepwear flammability rules, NIEHS covers flame retardants (the chemistry wool helps you skip), and the National Eczema Association discusses fabrics and sensitive skin. See References below.