Bamboo, viscose, modal and lyocell: are "eco" fabrics plastic?

The tag says “bamboo”. The marketing shows a green stalk and maybe a panda. The fabric feels like silk that went to yoga. Surely this one isn’t plastic?

Correct, it isn’t. But it isn’t bamboo either, in the way you’re picturing, and “not plastic” is a lower bar than “clean”. This piece covers the family of fabrics made by dissolving plant pulp and spinning it back into fibre: what they are, how they’re made, what the US regulator has done about the word “bamboo”, and what happens to the fibres when they shed. For shedding in general and what helps in the wash, see our article on synthetic clothes and microplastics.

Not plastic: what regenerated cellulose is

Cotton and linen are cellulose fibres that grow as fibres. Viscose, modal and lyocell start as cellulose that doesn’t: wood (eucalyptus, beech, pine) or bamboo, pulped, dissolved into a thick liquid, then pushed through tiny holes and set back into solid fibre. The polymer at the end is still cellulose, the same molecule as cotton. That’s why it’s called regenerated.

US textile law puts all of these under one generic name. The FTC’s rules define rayon as “a manufactured fiber composed of regenerated cellulose”, and allow the name lyocell for the version made by dissolving cellulose in an organic solvent with “no chemical intermediates”. Viscose is the everyday name for the most common kind of rayon, and modal is a subtype of rayon designed to be stronger.

Plastic, by contrast, is a synthetic polymer: polyester, nylon, acrylic, elastane. Nobody grows those. So on the question in the title, the answer is a clean no.

One relative is different: acetate. The FTC lists it separately, as a fibre made of cellulose acetate. That’s cellulose that has been chemically changed, not just regenerated. We cover it under common questions below.

How viscose and modal are made

The viscose process is well over a century old. Pulp is soaked in sodium hydroxide, then reacted with carbon disulfide to make a compound called cellulose xanthate, which dissolves into an orange-yellow syrup. That syrup is spun into an acid bath, where the cellulose comes back out as fibre.

Modal uses the same xanthate route, typically from beech pulp, tuned for a stronger fibre. Chemically, the step that matters most for the people making it is the same.

The review we drew on says viscose’s chemicals “can pose environmental and health risks” and that better recovery systems aim to reduce them. How well a given factory recovers them is the big variable, and it isn’t printed on any label. A life-cycle study of fibres made by the Austrian producer Lenzing, which assessed that company’s own production (we couldn’t confirm who funded it), found its modal and Austrian viscose had among the lowest impacts of the fibres compared, but viscose made in Asia “has a higher overall impact”, comparable to polyester. That study only went as far as the factory gate, and its subject was one company’s fibres.

Carbon disulfide and the people who make viscose

Carbon disulfide is a solvent with a long, grim occupational record, and much of that record comes from viscose plants. A 2009 review of the viscose industry lists its main health effects as coronary heart disease, changes to the retina, damage to peripheral nerves, effects on the brain, and effects on fertility.

The studies, roughly from strongest to most contested:

• Nerve damage at high exposure. In a Taiwanese viscose factory, nine workers in the fibre-cutting department (53%) had overt polyneuropathy, where air levels at fixed points reached 150 to 300 ppm. The authors warned that subclinical nerve damage “cannot be overlooked” at lower levels too.
• Heart deaths, and what happened when exposure fell. A Finnish cohort of 343 viscose workers had a 4.7-fold excess of heart disease deaths in the first five years of follow-up, compared with paper mill workers. After the plant cut exposure to its 10 ppm standard and moved workers with heart risk factors away from it, the relative risk fell to 1.0. That before-and-after is consistent with the exposure itself, not something else about the job, driving the excess, though the intervention changed who was exposed as well as how much.
• Subtler effects at lower exposures. In 11 Japanese rayon factories with average exposure around 5 ppm, exposed workers had higher odds of an increase in small bright spots on brain scans over six years (adjusted odds ratio 2.27). The authors found no dose-response and said the results should be read with caution. In a German rayon plant, workers with the highest long-term exposure had thicker carotid artery walls, a marker of atherosclerosis.

On heart disease overall, the literature genuinely disagrees. A 2002 meta-analysis of 11 cohort studies found a pooled relative risk of 1.56, which the authors called a “feeble correlation”. A critical review the same year found “remarkably little consistency” across studies, while accepting a heart effect is plausible. And the 2009 review that supports a 10 ppm workplace limit adds that female workers’ reproductive capacity “may not be adequately protected at exposures around 10 ppm”.

What none of this tells you is anything about wearing viscose. These are studies of people breathing the solvent for years at work. We found no evidence that the finished fabric exposes the wearer to carbon disulfide. The cost of viscose falls on the people who make it and the places they live, which is exactly why it’s worth knowing how your fabric was made.

Lyocell: a different solvent, recycled in a loop

Lyocell skips the xanthate step. The pulp dissolves directly in an organic solvent called NMMO (N-methylmorpholine N-oxide), and the fibre is spun out of that. That’s the “no chemical intermediates” in the FTC’s definition. Tencel, the best-known name, is a brand: the first commercial lyocell was sold under it by Courtaulds in the early 1990s.

The selling point is the solvent loop. A 2024 review, citing earlier work rather than its own measurements, says more than 99% of the NMMO is typically recovered and reused. In the Lenzing life-cycle study, its lyocell was among the lowest-impact fibres compared, with the same caveats as above.

It isn’t chemistry-free. Researchers have documented side reactions that make cellulose solutions in NMMO frequently unstable, which producers have to manage. And lyocell fibres fibrillate during wet abrasion: the surface splits into fine hairs, which is why it often gets extra finishing. Still, if you’re choosing between the common regenerated fibres, lyocell is the one whose main solvent isn’t carbon disulfide.

“Bamboo” fabric, rayon and the FTC

Fabric can be made from actual bamboo fibre, or from bamboo pulp run through the viscose process. In every FTC case below, the FTC said the “bamboo” sheets, towels and clothes were the second kind. The US regulator has been blunt about this since 2009: “Rayon is rayon, even if bamboo has been used somewhere along the line”. Any plant can be the cellulose source, “but the fiber that is created is rayon.”

The FTC’s position, as of November 2026: textiles can only be called bamboo “if they are made directly from actual bamboo fiber”. Rayon from bamboo can be labelled “rayon (or viscose) made from bamboo.”

It has enforced that repeatedly:

• 2009. The FTC charged four sellers with labelling rayon as bamboo fibre and with claiming it kept bamboo’s antimicrobial properties.
• 2010. Warning letters went to 78 retailers.
• 2013. Sears, Amazon, Macy’s and Leon Max agreed to pay penalties totalling $1.26 million over textiles the FTC alleged were labelled bamboo but were rayon.
• 2015. Bed Bath & Beyond, Nordstrom, J.C. Penney and Backcountry.com agreed to penalties totalling $1.3 million, settling FTC complaints that alleged they marketed rayon products as bamboo.
• 2022. Under proposed consent orders filed for the FTC, Kohl’s and Walmart were to pay $2.5 million and $3 million in civil penalties, which the FTC called by far the largest in this area, over what it alleged were dozens of rayon products marketed as bamboo. The orders also bar unsupported green claims.

These were settlements of FTC allegations, and the FTC’s announcements don’t say any company admitted wrongdoing.

The environmental point runs through every one of these. The FTC says turning bamboo into rayon “requires the use of toxic chemicals and results in hazardous pollutants”. The bamboo may grow fast, but by the time it’s a T-shirt, the process that made it is viscose. We made a similar point about bamboo dinnerware, where “bamboo” turns out to mean plastic with plant powder in it. Bamboo fabric is a much better deal than that: the fibre really is plant cellulose. It’s just not what the label suggests.

Do these fabrics shed, and do they break down?

They shed. Any fabric does, and regenerated cellulose is no exception. Our synthetic clothes article covers how much fabrics shed in the wash, including lab work showing cotton and rayon can release more fibre by weight than polyester.

The difference is what happens next. In a marine test, natural and regenerated cellulose fibres underwent complete biodegradation within about 35 days. One of its authors works for Lenzing, which makes viscose and lyocell. Polyester and polypropylene didn’t degrade over 428 days, and neither did the plastic portion of cellulose-plastic blends. In that test, at least, a viscose fibre in the sea was a short-lived problem; a polyester one wasn’t. Results vary: another lab study, co-authored by cotton-industry researchers, found cotton and rayon reached only about 50% biodegradation in seawater, though more than 70% in lake water and sludge, while polyester barely degraded.

Two caveats:

• Breaking down isn’t the same as harmless. In an earthworm study using additive-free fibres, viscose and lyocell had greater acute toxicity than polyester at high concentrations, and broadly similar effects at lower ones. The study drew a published critique and rebuttal. It’s one study in one species, but it’s a reason not to call these fibres “safe” just because they’re plant-based. Dyes matter too: viscose fibres eaten by invertebrates living in seagrass litter off Corsica carried Direct Red 28, a dye the authors note is carcinogenic for vertebrates.
• “Biodegradable” on a label is a different claim. In 2009 the FTC challenged unqualified “biodegradable” claims on bamboo rayon, saying the products “will not break down in a reasonably short time”. That’s about where most clothes end up, which is landfill or an incinerator, not seawater. Both things can be true: the fibre breaks down in water with microbes, and a T-shirt in a sealed landfill may not.

Why surveys sometimes count rayon as microplastic

Here’s a quirk that has bent the numbers. Early microplastic studies often lumped man-made cellulose in with plastic. In a much-cited 2013 study of fish from the English Channel, rayon was the most common “plastic”, at 57.8% of 351 pieces; the authors called it a “semi-synthetic cellulosic material”.

Telling rayon from cotton isn’t easy. Spectroscopists showed that with one common lab method, it was not possible to differentiate between man-made and natural fibres; other methods could. A Corsican study was titled, fairly, “When microplastic is not plastic”.

Better identification has changed the picture. When about 2,000 ocean fibres were chemically identified, only 8.2% were synthetic and 79.5% cellulosic; the authors stress fibres must be identified “before classifying them as microplastics”. So if you see a big microplastic figure dominated by fibres, it’s worth asking whether rayon was counted. Our explainer on how microplastics are measured goes into the methods.

Blends, thread and the bits that are still plastic

The fibre can be entirely plant-based and the garment still contain plastic. Viscose and modal are often blended with elastane for stretch or with polyester or nylon for strength, especially in socks and underwear. In the marine test above, the plastic part of a blend didn’t break down even when the cellulose did. Then there’s sewing thread, elastic waistbands, labels and prints, which care labels usually don’t cover. Our guides to where plastic hides in clothes and to recycled polyester go into those.

“Less plastic, not no plastic” is the honest version. A 100% lyocell shirt is about as close as manufactured fibre gets. A “bamboo” sock that’s half viscose and half polyester is still half plastic.

What LPP’s standard does with them

Under our standards, as of November 2026:

• Regenerated cellulose isn’t counted as synthetic. Viscose, modal, lyocell and “bamboo” fabric don’t count toward the 5% synthetic cap for textiles, because they aren’t plastic.
• We say which process. Where the maker discloses it, a listing names whether the fibre was made by the viscose route (carbon disulfide) or the lyocell route (NMMO). “Bamboo” fabric is recorded as regenerated cellulose, not as bamboo.
• We check the rest of the garment. A garment more than 5% synthetic on its fibre label is excluded. We also ask about thread, elastic, labels and prints, which that label can leave out. On a garment within the cap, synthetic thread, elastic or labels are allowed at plastic-minimal only if the listing names them, and a maker who won’t say what the thread is gets it recorded as synthetic.

Common questions

Does bamboo fabric have natural antibacterial properties?

Not if it’s bamboo rayon. The FTC has said rayon “does not retain any natural antimicrobial properties of the bamboo plant”, because, it charged, the manufacturing process eliminates them. If a garment claims antibacterial performance, ask what was added to make it so.

Is acetate plastic?

It’s a grey area, and a different case from viscose. Acetate is cellulose that has been chemically converted to cellulose acetate, rather than just dissolved and regenerated, and US rules give it its own fibre name. If you’re considering an acetate garment, ask the maker what it is and how it was made; our standard doesn’t yet set a specific rule for it.