The question of whether polyester fabric causes cancer centers not on the material itself but on the auxiliary chemicals used to manufacture and treat it. Polyester (polyethylene terephthalate or PET) is a synthetic polymer derived from petroleum. Scientific and regulatory bodies conclude that the finished polyester polymer, as found in clothing and textiles, does not directly cause cancer. However, the manufacturing process introduces chemical substances that may remain as trace residues, which is the source of public concern.
The Chemical Structure of Polyester
Polyester fibers are composed of long, repeating molecular chains of polyethylene terephthalate, created through a process called polycondensation. This reaction links monomers into large, stable polymers with a high molecular weight. The process is designed to create a chemically inert substance.
The final PET polymer is semi-crystalline and resistant to moisture, solvents, and biological degradation. This stability means the polymer does not easily break down under normal conditions of use or wear to release toxic components.
Specific Additives Used in Synthetic Fabrics
While the core polymer is stable, textile manufacturing requires auxiliary chemicals that can remain as residual substances. These compounds, used for polymerization, coloring, and performance finishing, are the focus of health investigations related to synthetic fabrics. The most common concern involves antimony, a heavy metal used as a catalyst to speed up the PET polymerization reaction.
Antimony
Antimony trioxide is the standard catalyst, classified by the International Agency for Research on Cancer (IARC) as “possibly carcinogenic to humans” (Group 2B). This classification is based on sufficient evidence from animal studies where high concentrations caused lung tumors in rats. Residual antimony remains embedded within the fiber structure of consumer textiles, and the risk is related to its potential to leach out.
Dyes and Finishing Agents
Another area of concern is the use of certain dyes that can break down into carcinogenic aromatic amines. Certain azo dyes are restricted globally because they can cleave under reductive conditions, such as prolonged contact with sweat, releasing known or suspected carcinogens. Regulatory bodies enforce strict limits on these specific amines in textiles that come into direct and prolonged contact with the skin.
Finishing agents applied for wrinkle and stain resistance also introduce chemicals, notably formaldehyde-releasing resins. Formaldehyde is classified by IARC as a “known human carcinogen” (Group 1), though its use in textiles is primarily associated with contact dermatitis. The resins slowly release small amounts of the chemical.
Exposure Routes and Scientific Consensus
Human exposure to these residual chemicals occurs primarily through dermal absorption and inhalation. Dermal absorption involves the migration of chemical residues from the fabric surface into the skin, a process that is generally minimal for stable fabrics. This leaching is exacerbated by factors such as heat, sweating, and friction.
Research assessing the health risk from trace elements on clothing has found high concentrations of antimony in some polyester garments. While the overall carcinogenic risk calculated for consumer exposure is consistently below acceptable limits, the non-carcinogenic risk (hazard quotient) for antimony leaching has been found to approach or exceed safety thresholds in some studies, highlighting the need for continued monitoring.
The second route is the inhalation of microfibers, tiny plastic fragments shed during wear and washing. These microplastics become airborne, raising concerns about potential long-term respiratory effects. High occupational exposure to synthetic fiber dust in textile factories has been linked to chronic lung conditions, but this exposure level is not comparable to that of the general public.
Global regulatory bodies, including the U.S. Environmental Protection Agency (EPA) and IARC, have not classified the finished polyester fiber itself as a carcinogen. The scientific consensus maintains that wearing polyester clothing poses a negligible cancer risk for the average person under normal conditions. The potential risk is confined to trace residual chemicals, which are subject to stringent regulatory limits.
Non-Carcinogenic Health Concerns
The most prevalent health issues linked to synthetic fabrics relate to immediate skin reactions and comfort issues. Allergic contact dermatitis is common, often triggered by residual disperse dyes or the formaldehyde-releasing resins used for wrinkle resistance. These reactions cause redness, itching, and rashes.
Polyester’s lack of breathability traps moisture and heat close to the skin. This humid microclimate encourages bacteria and fungi growth, which can lead to body odor and exacerbate existing skin conditions. Furthermore, certain chemicals, such as bisphenol A (BPA) found in recycled polyester, and phthalates, are known endocrine disruptors. These substances are a health concern due to their potential to interfere with hormonal signaling, representing a systemic risk distinct from carcinogenicity.