Fleece is a synthetic textile known for its soft, warm texture, but its composition and manufacturing raise questions about safety and sustainability. The base material is not acutely poisonous, but chemical additives and the long-term environmental impact of the fabric present recognized health and ecological concerns. These concerns stem primarily from chemical treatments applied to enhance performance and the physical breakdown of the plastic fibers over time. Understanding the material’s origin clarifies the specific risks associated with its use.
What is Fleece Made Of
Standard fleece fabric is a plastic textile, most commonly made from polyethylene terephthalate (PET). PET is the same polymer used for plastic water bottles, making fleece essentially a form of polyester. The manufacturing process often utilizes recycled PET (rPET), where plastic bottles are cleaned, shredded, and melted into pellets. These pellets are extruded through fine nozzles called spinnerets to form continuous polyester filaments, which are then spun into yarn.
The signature fluffy texture of fleece is created in the final step, where the fabric is brushed to raise the fibers, a process called napping. This creates a dense, insulating layer that traps air and provides warmth without significant weight. This structure makes fleece popular, but it also contributes to its tendency to shed tiny fibers.
Chemical Exposure Concerns
The primary health concerns relate to chemical substances added during or after manufacturing to give the fabric specific performance features. These finishing chemicals are not chemically bonded to the fibers, allowing them to leach out over time with wear, washing, or direct contact.
Flame retardants are often applied to synthetic fabrics like fleece, particularly in children’s sleepwear or blankets. These chemicals, such as organohalogens or phosphorus-based compounds, inhibit burning but have been linked to health issues like endocrine disruption and neurotoxicity. Studies show that these chemicals can be rapidly absorbed through the skin.
Water-repellent coatings and dyes also contribute to the chemical load. Outdoor gear is often treated with per- and polyfluoroalkyl substances (PFAS), known as “forever chemicals” for their persistence in the environment and the human body. Azo dyes, used for bright colors in fleece, can break down into carcinogenic aromatic amines upon contact with skin, potentially causing allergic reactions or dermatitis.
The Environmental Toxicity of Microfibers
Beyond chemical exposure, the physical structure of fleece creates a widespread environmental problem through microfiber shedding. Fleece textiles are a significant source of these microscopic plastic threads, released every time the garment is washed or worn. A single wash cycle can cause a garment to shed tens of thousands of fibers.
These microfibers, fragments of the base polyester plastic, travel through wastewater systems. Although treatment plants filter out a large percentage of fibers, the remaining small fraction can still escape into rivers and oceans due to the sheer volume of daily laundry. Captured fibers often end up in sewage sludge, which is used as fertilizer on agricultural land, transferring the microplastics to terrestrial environments.
Once in the environment, these plastic fibers do not biodegrade and persist, contaminating the food chain. Aquatic organisms can ingest the fibers, which accumulate up the food chain, potentially reaching humans through diet. Microfibers can also act as carriers for other pollutants, absorbing surrounding chemicals and transporting them into the bodies of ingesting organisms.
Reducing Risk and Choosing Safer Fabrics
Consumers can take actions to minimize risks associated with existing fleece products. To reduce the environmental impact of microfiber shedding, washing fleece garments less frequently is effective.
Reducing Microfiber Shedding
Use a cold water cycle and shorter wash times to decrease the friction that causes fiber loss.
Utilize specialized laundry bags or ball devices designed to catch microfibers before they enter the drain.
Install a dedicated filter on the washing machine’s discharge hose to prevent the majority of microplastics from reaching the wastewater system.
Choose garments that are undyed or free of stain and water-repellent finishes to lower the risk of exposure to chemical additives.
For new purchases, prioritizing natural fiber alternatives eliminates the plastic base material and the associated microfiber problem. Fabric options like organic cotton fleece, hemp-cotton blends, and merino wool provide warmth and softness without shedding synthetic microfibers. Some manufacturers are developing innovative biodegradable synthetic options, such as polylactic acid (PLA) fleece made from fermented plant starch, which offers performance similar to polyester but with reduced environmental persistence.