Among its many other qualities, wool is remarkably resistant to flame. International Wool Textile Organisation (IWTO) explains how and why the natural fibre is able to withstand fire.

The Facts Behind Wool’s Flame Resistance

Wool has long been recognised as a fibre with the ability to protect wearers against extreme heat, cold and open flame. Military authorities have often chosen it as the fibre of choice for outer garments for their soldiers to wear in combat conditions. Even today, both the military and emergency workers continue to use base-layer wool garments due to their health and safety benefits.

IWTO Member Australian Wool Innovation (AWI) recently funded a scientific study to investigate the fire resistance of various fabrics, in order to measure wool’s flame resistance relative to that of other fabrics. The study found that wool outperformed other fabrics in this area by quite a sizeable margin. It was found that entirely synthetic fibres, on the other hand, such as polyester and polypropylene performed the worst.

How Merino Wool Protects The Skin

Wool fibres have a natural resistance to burning, even when exposed to an ignition source for long periods.  In the study, wool was put through a variety of tests alongside polypropylene, polyester, nylon, rayon and spandex. In one test, the fabrics were exposed to open flames over a simulated skin, to see how well they protected the skin. The results were compared against an undamaged control to assess the extent of the damage.

The findings: the skin that had been protected by Merino wool blend showed minimal damage – in fact, it was similar to the undamaged control. The skins  that was under polyester and polypropylene, however, displayed significant damage. Both the polyester and polypropylene test skins displayed breaks  in the epidermis, loss of voids, and discoloration of  tissue.

In a tougher test using accelerant-fuelled flame, the polyester and polypropylene-covered skin was even more severely damaged, while the Merino-covered skin remained very close to the undamaged control.

“This new test method demonstrated that while synthetic fabrics might be the most cost effective with regard to procurement, they offer very little protection to the wearer under the applied test conditions,” says AWI’s Angus Ireland.

Burned: Protecting the Protectors

The AWI experiment is not the only recent effort to understand the ways in which different fabrics protect/fail to protect against the damage that can come from fire. A recent documentary film,  Burned, tells the true story of Diane Cotter, wife of lifetime firefighter Paul Cotter, whose quest to understand her husband’s cancer revealed the vast exposure to forever chemicals across the entire U.S. fire community.

Her efforts led to the discovery of huge amounts of PFAS in firefighter turnout gear – some of the highest levels of fluorine seen in any kind of textile.

The actor Mark Ruffalo, a named producer, became involved with the project during the film’s development, when director Elijah Yetter-Bowman was working closely with Rob Bilott, the lawyer who had taken on DuPont’s long history of chenical pollution. That story was the subject of the 2019 film Dark Waters, starring Mark Ruffalo as Rob Bilott.

Burned: Protecting the Protectors is available for fire departments, non-profits and other organisations via

Watch the trailer here.

Learn All You Need to Know About the International Wool Industry

For more information on the wool industry around the world, take a look at our fact sheets, statistics and guidelines. To find out more about wool’s flame resistance qualities in particular, take a look at our page dedicated to the topic.