Rayon, often called viscose, is a semi-synthetic fiber derived from cellulose, the main structural component of plants. The raw material, typically wood pulp from trees, is sourced from nature, but its transformation into a textile fiber is a highly industrialized and chemical-intensive process. This manufacturing method, particularly the common Viscose process, creates significant environmental damage and poses serious health risks for workers. Although rayon is sometimes marketed as a sustainable alternative, the chemical processing required results in substantial costs to both ecosystems and human well-being.
Unsustainable Cellulose Sourcing
The initial negative impact of rayon production begins with the acquisition of the raw material: wood pulp. An estimated 200 million trees are logged annually for all cellulose-based fabrics, including rayon and viscose. Approximately 30% of this pulp is sourced from ancient and endangered forests (AFs) rather than sustainably managed plantations.
Deforestation of these high-conservation-value forests leads to severe habitat destruction and a loss of global biodiversity. Clearing biodiverse forests to establish monoculture tree farms also reduces the area’s carbon storage capacity. This unsustainable sourcing threatens species like Sumatran tigers and orangutans.
Toxic Air Emissions from Chemical Processing
The standard Viscose process requires a series of harsh chemical reactions that result in the release of volatile compounds into the atmosphere. A primary chemical agent used is carbon disulfide (CS2), which converts the cellulose into a soluble intermediate called cellulose xanthate. This compound is highly volatile and readily evaporates, making it the most notorious airborne pollutant from rayon manufacturing.
Global rayon production is the source of the majority of industrial carbon disulfide emissions worldwide, with factories releasing around 250 grams of CS2 per kilogram of rayon fiber produced. Once released, carbon disulfide contributes to localized air pollution, acting as a potent neurotoxin that impacts the health of nearby communities and livestock, alongside other pollutants like sulfur, hydrogen sulfide, and various volatile organic compounds (VOCs).
Water Contamination from Effluent Waste
The chemical process generates a substantial volume of liquid waste, known as effluent, which is a major source of water contamination. After the cellulose xanthate is formed, it is extruded into a coagulation bath composed primarily of sulfuric acid, sodium sulfate, and zinc sulfate. This bath regenerates the cellulose into solid rayon fibers.
The spent bath water and wash waters contain high concentrations of residual chemicals, including highly acidic sulfuric acid, caustic soda (sodium hydroxide), and heavy metals like zinc. If this effluent is not treated effectively, its discharge into local waterways dramatically increases the water’s acidity and introduces toxic contaminants. Zinc is a regulated heavy metal that can bio-accumulate and damage aquatic ecosystems, even at low concentrations.
Occupational Health Risks
Factory workers face the most direct and severe health consequences due to exposure to the chemicals used in the Viscose process. Inhalation of carbon disulfide vapor is the primary internal factory hazard, causing both acute and chronic poisoning. Workers exposed to CS2 over time show an increased risk of developing cardiovascular disease and severe neurological damage.
Chronic exposure has been linked to peripheral neuropathy (numbness and weakness in the limbs) and encephalopathy, a brain disorder. Symptoms can range from memory impairment and psychosis to severe cardiovascular issues and signs resembling Parkinsonism. Even at current, lower exposure limits, subclinical effects on the nervous system and glucose metabolism have been observed in workers.
Cleaner Manufacturing Alternatives
To mitigate the environmental and health hazards of conventional Viscose rayon, cleaner manufacturing alternatives have been developed. The Lyocell process is the most advanced of these methods, known commercially by the brand name Tencel. Lyocell avoids the use of carbon disulfide and other highly toxic chemicals by dissolving the wood pulp directly in a non-toxic organic solvent, N-methyl morpholine N-oxide (NMMO).
This process operates as a “closed-loop” system, meaning the solvent is recovered and recycled at a high efficiency, often exceeding 99%. This recycling minimizes the release of contaminated wastewater and gaseous emissions into the environment. Another alternative is Modal, a variation of Viscose that is considered cleaner because it often uses sustainably sourced beech wood and incorporates improved chemical recovery systems.