Watch: Scientists breed flame-resistant cotton, without added chemicals

A research team at the USDA has developed new lines of cotton that are naturally flame-resistant — even putting themselves out when lit.

The ability could help cut back on the use of flame retardants, chemicals applied to a vast array of commercial products, like clothing, carpets, upholstery, and mattresses, to prevent cotton’s flammable fibers from burning people if there’s a fire — but which come with a variety of negative health and environmental impacts.

Chemicals and fire: While flame retardants are effective and have improved fire safety, many of them come with environmental and health costs. 

According to the NIH, a growing body of research associates them with, among other things, higher risks of cancer, immune system disruption, and adverse effects on fetal development.

Despite many of them being phased out of production, their hardiness means they can build up in the environment, causing damage to places, people, and animals. 

Natural flame retardants: The self-extinguishing cotton lines, published in PLOS One, were bred by using existing lines of cotton, with no recombinant genetic modification — or the extra rules and regulations that come with it. 

That means, as the Daily Beast’s Maddie Bender pointed out, that it can be grown without the arduous approval process for GMOs.

“Use of these lines to develop commercial cultivars creates an opportunity to improve the safety of cotton products while reducing the economic and environmental impacts of chemical flame retardants,” said study senior author Brian Condon, the retired research leader at the USDA’s Agricultural Research Service (ARS) Cotton Chemistry and Utilization Research Unit.

Scientists have known that brown-colored cotton can be flame resistant, but the team’s new lines are “the first report of a white cotton line with the property,” USDA cotton chemistry researcher Gregory Thyssen told the Daily Beast.

The self-extinguishing cotton lines were bred by using existing lines of cotton, with no recombinant genetic modification.

ARS researchers Johnie Jenkins and Jack McCarty began with 11 parent cultivars, none of which possessed flame resistance traits. Breeding these 11 different cultivars together in a variety of combinations, the team developed 257 new lines.

They winnowed these down to the best 30 candidates for the next year’s breeding season, per the Daily Beast, then made cuts again, selecting the best ten to work with the year after that.

They then wove five textiles using the most flame-resistant varieties.

“Of the textiles fabricated from the five superior [lines], four exhibited the novel characteristic of inherent flame resistance,” the authors wrote in their study. (The others were “rapidly and completely consumed by flame.”) 

When put through a standard 45° incline flammability test, the four fabrics self-extinguished — actually putting themselves out. 

The natural flame retardants the team bred did not derive their resistance from one simple trait; instead it was “obviously due to an uncommon combination of alleles” — a bunch of genetic mixing and matching across sundry regions of the genome. 

The complex formula for flame resistance meant old-school breeding was actually a better choice than more targeted genetic engineering. 

Looking ahead: The flame-resistant cotton lines don’t sacrifice the quality traits that growers already look for in cotton, making them appropriate for commercial growing. 

After growing an even larger field of the cotton this summer, the ARS will begin making seeds available to growers, Thyssen told the Beast. 

They will also make new fibers like yarn to continue to put to the test, Thyssen said, including trying to figure out the durability of the natural flame retardants — for example if multiple washings may erode the effect. 

We’d love to hear from you! If you have a comment about this article or if you have a tip for a future Freethink story, please email us at [email protected].