Synthetic fleece is great—until you consider the fact that every time it's washed, it releases thousands of microfibers into the environment. Microscopic plastic fibers may now be one of the most common types of plastic debris found in samples from the environment, including animals, ecologist and evolutionary biologist Chelsea Rochman tells NPR, and that means we humans are likely eating the synthetic fibers without realizing it. Previous studies have found microfibers in table salt and fish; last year, Alternet explained that marine life is particularly prone to ingesting microfibers because they go from the washing machine through the sewage system and into various waterways. Microfibers are, it turns out, more pervasive in the environment than even microbeads—which were banned in the US in 2015 over similar problems.
In 2011, one ecologist found that 85% of human debris on shorelines around the world is synthetic microfiber. Now, outdoor outfitting company Patagonia—which often uses microfiber in its products—is also looking into the problem, and has found that a polyester fleece jacket shed as many as 2 grams of microfibers (that's an amount weighing more than a paperclip) each time it's washed, and even more when washed in a top-loader. The next question: Are these microfibers harmful to wildlife and humans? The answer is not yet clear, but one conservationist says he's not waiting to find out; he recommends washing your microfleece as little as possible. The Guardian reported last year that there are also a few ideas floating around for products that would trap microfibers in the washing machine rather than allowing them down the drain. (This microfiber fabric generates its own electricity.)