Fleece is a favored fabric for its warmth and soft texture, widely used in clothing, blankets, and outdoor gear. However, questions often arise regarding its potential toxicity and environmental footprint. This article explores fleece’s chemical makeup, manufacturing processes, and environmental implications.
Understanding Fleece Composition
Most fleece fabric is primarily composed of polyester, a synthetic fiber derived from polyethylene terephthalate (PET) plastic. This material is the same type of plastic used in many beverage bottles. Polyester fleece is known for its ability to trap heat, offering warmth without excessive weight, and it also possesses moisture-wicking properties that draw sweat away from the skin.
The manufacturing process involves melting petroleum-derived plastic into a thick liquid, which is then hardened and woven into thin filament threads. These threads are then knitted into a dense material. The fabric’s characteristic soft, fuzzy surface is created by brushing out the dense material, a process that creates a napped or brushed texture. While polyester is the most common base, some fleece varieties may incorporate blends with cotton, rayon, or hemp to alter texture and properties.
Chemicals and Additives in Fleece
Beyond the base polyester, fleece fabrics often undergo various treatments that involve additional chemicals. Dyes, such as azo dyes, are frequently used to achieve a wide range of colors. These dyes are favored by manufacturers for their low cost and ability to adhere well to fabrics, making up a significant portion of fabric colorants.
Fleece can also be treated with flame retardants to reduce flammability. These can include organophosphate flame retardants (OPFRs) or brominated compounds like tetrabromobisphenol A (TBBPA). Water-repellent and stain-resistant coatings, often containing per- and polyfluoroalkyl substances (PFAS), are sometimes applied to enhance performance, particularly in outdoor gear. Anti-pilling agents are also added to maintain the fabric’s appearance by preventing the formation of small fiber balls on the surface.
Health Considerations of Fleece Exposure
The chemicals present in fleece can raise health concerns through various exposure pathways, including skin contact and inhalation. Azo dyes, for example, can break down upon contact with skin, releasing aromatic amines that may cause skin irritation, allergic reactions, and dermatitis. Some aromatic amines have also been linked to cancer.
Flame retardants, like certain organophosphate compounds, have been associated with potential harm to the nervous, reproductive, and skeletal systems. Some flame retardants, such as TBBPA, have also been linked to cancer. PFAS chemicals, used for water and stain resistance, are persistent in the environment and the body, and while direct dermal exposure data is limited, exposure through other routes has been linked to increased cholesterol, metabolic disorders, and reproductive and developmental toxicity. Additionally, polyester manufacturing can release volatile organic compounds (VOCs) and by-products like 1,4-dioxane, a weak human carcinogen, into wastewater.
Microplastic Shedding and Environmental Concerns
A significant environmental concern with synthetic fleece is the shedding of microplastics, tiny plastic fibers released during washing and wear. A single fleece garment can shed hundreds of thousands of microfibers in one washing cycle, with some studies suggesting over 700,000 fibers can be released from an average laundry load. These microfibers are often too small for wastewater treatment plants to fully capture, with up to 40% entering waterways.
Once in aquatic environments, microplastics are consumed by marine life, potentially leading to physical and chemical imbalances, growth and reproduction issues, and gastrointestinal blockages. These microplastics have been found in oceans, rivers, tap water, and even in food sources like table salt, raising indirect human exposure concerns. The accumulation of these non-biodegradable fibers contributes significantly to global plastic pollution.
Choosing Safer Fleece and Alternatives
For consumers concerned about fleece’s impact, several strategies can mitigate potential risks. Reducing washing frequency and opting for spot cleaning can significantly decrease microfiber shedding. When washing, using cold water, liquid detergent instead of powder, and shorter cycles can also help.
Specialized laundry bags or washing machine filters designed to capture microplastics can prevent a large percentage of fibers from entering waterways. Choosing fleece made from recycled materials, such as recycled plastic bottles, can reduce the demand for new petroleum-based plastics, though it does not eliminate microplastic shedding. Exploring natural fiber alternatives like organic cotton, wool (including merino wool which can be processed into a fleece-like fabric), hemp, linen, and bamboo offers options that are generally more breathable, biodegradable, and free from many synthetic chemical treatments.