Viscose

Viscose is a semi-synthetic fiber made by chemically dissolving wood pulp cellulose in sodium hydroxide and carbon disulfide (CS2), then regenerating it into filament.

The heaviest health burden falls on factory workers, where carbon disulfide exposure is linked to peripheral neuropathy, ischemic heart disease, and excess mortality among spinners. For you as the wearer, the concern is residual processing chemicals: carbon disulfide byproducts and dye and finishing agents can remain in the fabric and trigger allergic contact dermatitis or skin irritation in sensitive people, and some viscose gets the same formaldehyde-based wrinkle finishes used on cotton. On the comfort side, viscose is plastic-free and breathable, letting air circulate against your skin better than petroleum synthetics.

Favor closed-loop lyocell (such as TENCEL) as the cleaner regenerated-cellulose alternative, since it recovers its solvent and skips carbon disulfide, and look for OEKO-TEX STANDARD 100 on any viscose you buy. Wash new pieces before wearing.

Conventional viscose production releases hazardous air and water pollutants and is often tied to deforestation of ancient and endangered forests.