If gas stove discourse has exposed you to the wonderful world of everyday exposures to environmental pollution, might I suggest another culprit that is guaranteed to get your knickers in a twist? Flame retardants are chemicals that are used to treat every manner of household item, from mattresses to electronics to building insulation to the clothes on your back. They slow the spread of fire, but at a cost: In recent years, scientists have tied these chemicals (of which there are hundreds) to immune disruption; reproductive harm; cancer; fetal development issues; and neurologic dysfunction.
And that’s all before a fire actually starts. Firefighting foam used to extinguish blazes may contain perfluoroalkyl and polyfluoroalkyl substances (PFAS), so-called forever chemicals that can be toxic to humans.
In a surprising development within the field of materials science, researchers at the U.S. Department of Agriculture have created a kind of cotton that naturally self-extinguishes when set on fire. And they did it by interbreeding existing lines of cotton, meaning that farmers can grow this cotton without a lengthy approval process. A study describing this new line of cotton was published on Jan. 18 in the journal PLoS ONE.
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“This is the unexpected cherry on top of a long, fruitful and still ongoing USDA project involving many scientists, years and locations,” Gregory Thyssen, a cotton chemistry researcher at the USDA Agricultural Research Service, told The Daily Beast in an email. While researchers have previously identified natural flame retardant properties in brown-colored cotton, “The new study is the first report of a white cotton line with the property,” he said.
Thyssen and his colleagues bred 11 cotton cultivars together that are naturally proven to be better than other lines at slowing down fire. The cultivars were bred with one another in different combinations and then were self-pollinated to produce hundreds of new cotton lines.
From there, researchers grew 257 lines and analyzed the flame-slowing capabilities of the fibers, choosing the 30 best and worst lines to grow the next year, and the five best and worst of those to grow the year after.
The results of the selective breeding spoke for themselves. According to the study, textiles woven from four of the five most flame-retardant lines self-extinguished when set on fire at a 45-degree angle. One of the most flame-retardant lines, and all of the least flame-retardant lines, “were rapidly and completely consumed by flame.”
Moreover, genetic sequencing of these new lines revealed that their superpower didn’t seem to arise from a random mutation or a single gene, but rather a complex interaction that compounded the flame-retardant effects of multiple genetic regions. Because the researchers still have to work out the particulars of this interaction, artificial selection ended up being a more successful approach than adding or removing genes via genetic engineering. “Genetic engineering of this trait is simply not an option at this point,” Thyssen said.
Moreover, in the U.S., multiple federal agencies play a role in evaluating genetically modified organisms, and GMOs have been met with public opposition despite the evidence that they are safe for consumers. Because it was created naturally by selective breeding, the self-extinguishing cotton avoids these issues entirely.
Thyssen said that the team plans to grow even larger fields of the new cotton varieties in the upcoming growing season, from May to September. As soon as they are able to increase the amount of seeds, the researchers will release them to growers for their own breeding programs. The cotton harvested from the season will also be used to make yarn and different types of textiles, which the researchers will then test for quality and flammability.
One question on everyone’s mind, Thyssen said, is the durability of the cotton’s flame retardant trait: Will textiles made from it self-extinguish after many washes, or must they eventually be treated with chemicals? There aren’t any answers yet. What’s clear, though, are the countless benefits reaped by phasing out toxic flame retardants from everyday life.
