Rayon as a finished fabric poses little direct chemical threat to the person wearing it, but the story gets considerably darker when you look at how it is made. The viscose process, which accounts for most of the world’s rayon, relies on carbon disulfide, a volatile solvent with a long and grim track record of harming factory workers’ nervous systems and hearts. For consumers, the risks are subtler and mostly shared with other textiles: trace chemical residues, dye-related irritants, and formaldehyde finishes. Separating the factory floor from the clothing rack is the key to understanding whether rayon deserves its growing reputation as a “toxic” fabric.
Carbon Disulfide and the Workers Who Make Viscose
Turning wood pulp into silky rayon fiber requires dissolving cellulose in carbon disulfide (CS2), a colorless liquid that evaporates easily and is readily inhaled. Workers in viscose rayon plants, particularly those in fiber cutting and spinning departments, have historically been exposed to concentrations far above what the body can handle safely. In one study of a viscose plant, air concentrations of CS2 reached 150 to 300 parts per million in the cutting areas and 15 to 100 ppm in spinning zones, with estimated eight-hour averages of 40 to 67 ppm in the worst spots.1PubMed Central. Polyneuropathy induced by carbon disulphide in viscose rayon workers For perspective, occupational exposure limits for CS2 vary between just 1 and 10 ppm depending on the country.2PubMed. A review of health effects of carbon disulfide in viscose industry and a proposal for an occupational exposure limit
The nervous system takes the first and hardest hit. In that same plant study, over half of workers in the fiber cutting department had overt polyneuropathy, a condition in which peripheral nerves lose their ability to transmit signals properly, causing numbness, tingling, weakness, and pain in the hands and feet.1PubMed Central. Polyneuropathy induced by carbon disulphide in viscose rayon workers Even at exposure levels lower than those old industrial settings, researchers have found small but measurable drops in nerve conduction speed among CS2-exposed workers, and the damage worsened in a dose-response pattern as cumulative exposure climbed.3PubMed. Effects on the peripheral nervous system of workers’ exposure to carbon disulfide These findings have been replicated across studies in Finland, Sweden, Italy, and beyond, making this one of the more consistent occupational toxicology findings of the twentieth century.
The damage is not limited to peripheral nerves. A cross-sectional study of 134 male workers at a viscose rayon plant found that those with heavy CS2 exposure were dramatically more likely to develop what clinicians call psychoorganic syndrome, a cluster of symptoms including memory problems, difficulty concentrating, mood changes, and fatigue. Heavily exposed workers had roughly eighteen times the odds of being diagnosed with the condition compared to unexposed colleagues.4PubMed. Neuropsychiatric effects in workers with occupational exposure to carbon disulfide Intermediate exposure raised the risk too, though not as steeply.
Heart Disease Among Viscose Workers
If the nerve damage is alarming, the cardiovascular data is worse. A Finnish study followed 343 viscose rayon workers and an equal number of unexposed men over ten years, tracking deaths from coronary heart disease. By the end, 29 exposed workers had died of coronary heart disease compared to 11 in the control group. The estimated lifetime risk of dying from coronary disease across a thirty-year age span was about 32% for the exposed workers, against roughly 13% for the unexposed group.5PubMed. Ten-year coronary mortality of workers exposed to carbon disulfide
An earlier five-year follow-up of a related cohort had already flagged the pattern, showing a relative risk of nearly five for fatal heart attacks and close to four for all heart attacks combined among CS2-exposed workers. About a quarter of exposed men reported angina symptoms, roughly double the rate in controls.6PubMed Central. A follow-up study of coronary heart disease in viscose rayon workers exposed to carbon disulphide The researchers noted something striking: the more severe and specific the cardiac outcome measured, the stronger the link to CS2 exposure. Mild ECG changes showed only a small difference between groups, but fatal heart attacks showed a massive one. CS2 appeared not just to increase the incidence of heart disease but to worsen its prognosis once it developed.
Together, these studies paint a picture of a chemical that attacks the body on multiple fronts: peripheral nerves, the central nervous system, and the cardiovascular system. The evidence is strongest for workers who spent years in poorly ventilated factories, but it explains why occupational health agencies worldwide treat CS2 as a serious hazard and why tightening exposure limits has been a recurring regulatory priority.
Reproductive Health Risks for Factory Workers
The occupational concerns extend to reproduction. Reviews of the available evidence on workers in viscose rayon plants suggest that women with prolonged CS2 exposure may experience disruptions to menstrual patterns, while men may see declines in semen quality.7Journal of Infertility and Reproductive Biology. Carbon Disulfide (CS2) Exposure and Human Reproductive Health- A Narrative Overview The research base here is thinner than for nerve and heart effects, and much of it comes from older factory settings where exposure levels were higher than modern standards typically allow. Still, reproductive toxicity is one more reason the viscose industry’s occupational record looks so poor.
It is worth emphasizing that these reproductive findings apply to workers breathing CS2 fumes during manufacturing, not to consumers wearing a rayon blouse. The chemical is volatile, meaning it evaporates long before a garment reaches a store shelf. The risk sits firmly on the production side of the supply chain.
What About the Fabric You Actually Wear?
Once rayon leaves the factory and arrives in your closet, the CS2 is gone. The chemical risks that remain are the same ones shared by most textiles regardless of fiber type: residual finishing chemicals, dyes, and the physical properties of the fabric against your skin.
Formaldehyde is the most commonly flagged residue. It is used as a finishing agent across the textile industry to reduce wrinkling and improve fabric stability. A study that tested clothing intended for babies, toddlers, and pregnant women found formaldehyde in about 20% of samples, with a mean level of roughly 9 milligrams per kilogram. Interestingly, garments marketed as eco-friendly had slightly higher formaldehyde levels than regular ones, a counterintuitive result the authors attributed to variability in how “eco-friendly” is defined and regulated.8PubMed Central. Early-Life Exposure to Formaldehyde through Clothing The levels found were generally low, but the research highlights that labeling alone is not a reliable proxy for chemical safety.
Textile dyes and pigments introduce another category of residue. An analysis of infant clothing found that copper, zinc, and iron were the most abundant metals, consistent with their use in dyes. More concerning were trace levels of arsenic, cadmium, chromium, lead, and nickel, all of which exceeded the strictest safety limits for baby wear in some samples.9MDPI (Toxics). Heavy Metals in Infant Clothing: Assessing Dermal Exposure Risks and Pathways for Sustainable Textile Policies These metals can be present in any dyed fabric, not just rayon, but the finding underscores that chemical risk from clothing tends to come from finishing and dyeing rather than from the fiber itself.
Contact dermatitis is the most common skin reaction to clothing in general. Formaldehyde and thiazolinone-based preservatives are among the known triggers, and the reaction is allergic in nature, meaning it depends on individual sensitivity rather than a universal toxic threshold.10PubMed Central. Allergies caused by textiles: control, research and future perspective in the medical field If you have ever gotten an itchy rash from a new garment that went away after a few washes, chemical residue is a plausible explanation. Washing new clothes before wearing them is one of the simplest ways to reduce your exposure to these finishing chemicals, regardless of fiber type.
Rayon in Tampons and the Toxic Shock Scare
Rayon is widely used in tampons, and periodic alarm about this shows up in health forums and social media. The concern traces back to the toxic shock syndrome (TSS) crisis of the early 1980s, which was linked to high-absorbency tampons. Because rayon is highly absorbent, it sometimes gets blamed for the TSS risk.
The research does not support singling out rayon. A laboratory study directly comparing all-cotton tampons to cotton-and-rayon blends found that cotton tampons produced the same amount of, or more, toxic shock syndrome toxin than the blended versions, under both oversaturated and half-saturated conditions.11PubMed. Comparison of cotton and cotton/rayon tampons for effect on production of toxic shock syndrome toxin TSS risk has more to do with absorbency level and how long a tampon is left in place than with whether the fibers are cotton or rayon. The “rayon tampons are dangerous” narrative persists online, but it does not hold up against the comparative evidence.
That said, some consumers prefer organic cotton tampons for reasons unrelated to TSS, such as avoiding the bleaching agents and synthetic fragrances that can be present in conventional products. Those are reasonable preferences, but they are about general chemical avoidance rather than a specific danger unique to rayon fibers.
How Rayon Compares Environmentally
Beyond personal health, many people asking whether rayon is “bad” are also thinking about its environmental footprint. The picture here is mixed. On one hand, viscose production generates chemical waste including zinc compounds and sulfuric acid byproducts, and the sludge left behind contains a complex mixture of minerals and precipitates.12KnE Materials Science. Investigation of Viscose Rayon Manufacturing Sludges, Considered as a Raw Material for Zinc Production Hydrogen sulfide, a toxic gas with its own suite of health effects, is another emission from viscose plants. Even chronic low-level exposure below 10 ppm has been associated with respiratory, neurological, and eye-related symptoms in surrounding communities.13PubMed Central. Low level exposure to hydrogen sulfide: a review of emissions, community exposure, health effects, and exposure guidelines
On the other hand, once rayon becomes a garment and eventually enters the waste stream, its cellulose-based structure gives it a significant advantage over synthetic fibers. Controlled biodegradation experiments have shown that cotton and rayon microfibers break down in both freshwater and marine environments, while polyester microfibers essentially persist indefinitely.14PubMed. Microfibers generated from the laundering of cotton, rayon and polyester based fabrics and their aquatic biodegradation More detailed testing has confirmed that rayon reaches over 70% biodegradation in freshwater with activated sludge and about 50% in seawater, while polyester does not appreciably degrade at all.15PubMed. Aerobic biodegradation in freshwater and marine environments of textile microfibers generated in clothes laundering: Effects of cellulose and polyester-based microfibers on the microbiome So rayon contributes far less to the microplastic crisis than polyester, nylon, and acrylic do, even though every wash cycle sheds fibers from all fabric types.
The environmental tradeoff, then, is front-loaded: dirty production, relatively clean end-of-life. Whether that is a net positive or negative compared to polyester (clean-ish production, permanent microplastic pollution) depends on how you weigh each stage.
Closed-Loop Processes and Whether They Change the Equation
Not all rayon is made the same way. The viscose process, which uses carbon disulfide and generates hydrogen sulfide, is the oldest and most common method. But a newer category of regenerated cellulose fiber, often sold under brand names like Tencel, uses a different solvent system based on an organic compound called NMMO (N-methylmorpholine N-oxide). In this process, the solvent is captured and recycled at rates above 99%, rather than being released into the air or water.
Lyocell-type fibers produced this way avoid the CS2 exposure problem almost entirely. There is no carbon disulfide in the process and no hydrogen sulfide byproduct. This matters for factory workers most of all, but it also reduces the environmental emissions that can affect communities near production facilities. The finished fabric is still cellulose-based, so it retains the biodegradability advantage over synthetics.
The catch is cost. Lyocell fibers are more expensive to produce than conventional viscose, so they tend to show up in mid-range and premium garments rather than fast fashion. A garment labeled simply “rayon” or “viscose” on the care tag was almost certainly made using the conventional CS2 process. If avoiding that supply chain matters to you, look specifically for lyocell or Tencel on the label.
Practical Takeaways for Everyday Choices
If you are choosing clothes for yourself, wearing rayon is not going to poison you. The finished fabric does not contain meaningful CS2 residue, and the trace chemicals it may carry (formaldehyde, dye metals) are present at low levels and shared across the textile industry. A few common-sense habits reduce even that modest exposure:
- Wash before wearing: A cycle in the washing machine removes a large share of residual finishing chemicals and loose dye.
- Check labels on baby clothes: Infants have more permeable skin and are more vulnerable to trace metals and formaldehyde. Looking for certified labels (like OEKO-TEX Standard 100) provides somewhat more assurance than generic “eco-friendly” branding, which as noted earlier does not reliably correlate with lower chemical residues.
- Choose lyocell when possible: If you want to avoid supporting the CS2-dependent supply chain, lyocell is the most direct alternative that still gives you a cellulose-based fabric with similar drape and breathability.
For tampon users specifically, the fiber composition matters far less than absorbency level and changing frequency. Switching from rayon-blend to all-cotton tampons does not reduce TSS risk based on the available comparative data, so make that choice based on comfort and other preferences rather than fear of rayon.
Who Actually Bears the Risk
The uncomfortable reality of the rayon question is that the chemical risks are real but unevenly distributed. Workers in viscose rayon factories, particularly in countries with lax enforcement of occupational health standards, face a genuine and well-documented threat to their nervous systems, hearts, and reproductive health. Communities living near viscose plants face exposure to hydrogen sulfide and other emissions. Consumers in wealthy countries, meanwhile, face negligible risk from the finished product and rarely encounter the supply chain that produced it.
This gap between who produces and who consumes is not unique to rayon. It runs through much of the global textile industry. But rayon’s reliance on carbon disulfide makes the production-side hazard unusually severe and unusually well-studied. The occupational epidemiology on CS2 stretches back more than seventy years, and the findings have been consistent across countries and decades: high exposure damages nerves, brains, hearts, and reproductive systems. Modern exposure limits are far tighter than they once were, but enforcement varies enormously by region. Much of the world’s viscose production has shifted to countries where workplace monitoring and regulatory oversight are inconsistent.
When people ask whether rayon is bad for them, the honest answer depends on which “them” you mean. If you are wearing it, the answer is essentially no. If you are making it under poor working conditions, the answer is emphatically yes.