Technological breakthroughs

An international research team spanning four institutions across four countries has published scientific evidence that a specially formulated liquid detergent can substantially cut the release of synthetic textile fiber fragments into wastewater and the atmosphere during machine laundering — a globally significant but underappreciated source of microplastic pollution.

Synthetic Fiber Fragments — A Global Problem Without a Clear Solution

Every time a polyester sweater or sports garment is washed, millions of microscopic plastic fibers — thinner than a human hair — silently escape with the wastewater, percolate through soil, flow into waterways, and ultimately enter the human food chain. Synthetic fiber fragment (sFF) pollution is becoming one of the most serious environmental issues of the 21st century, yet source-reduction options remain scarce. A new study published in Cleaner Materials points to a surprising avenue: reformulating liquid laundry detergent.

The study was conducted at four independent institutions in the United States, Spain, Italy, and Germany, using four different washing machines, four types of polyester fabric, and across two phases: machine washing and machine drying. The single common variable was the pair of detergents under comparison: a widely available conventional liquid detergent (detergent A) and a novel 'low-shed' liquid detergent (detergent B), co-developed by BASF and Inditex.

According to the International Textile Exchange, over 60% of global fiber production is now synthetic — predominantly polyester and polyamide (nylon). Each wash cycle dislodges tiny fibers from fabric surfaces; these travel through drainage systems, pass through wastewater filters, and enter aquatic environments. In the world's oceans, they are the most prevalent form of microplastic. Meanwhile, the dryer exhaust pathway — where fiber fragments are released directly into the atmosphere — has received far less scientific attention, despite evidence that this pathway may be equally or more significant than wastewater.

How the 'Low-Shed' Detergent Works

Detergent B — commercialized as 'The Laundry' and distributed through Zara Home — is not a conventional detergent with minor improvements. It was designed from the ground up with one specific objective: to protect fabrics from mechanical abrasion inside the washing drum, which is the direct cause of fiber fragmentation.

"The detergent generates a thick, long-lasting creamy foam that acts as a cushion between fabric surfaces inside the drum, reducing friction and limiting fiber fragment release at the point of origin."— Holden et al., Cleaner Materials 2025

The formulation contains 25% active matter, combining two surfactants: a non-ionic surfactant for creamy foam formation, and a second non-ionic surfactant with a cationic component (ethoxylated amine) that directly assists in reducing fiber shedding. Supporting ingredients include: a chelating agent to sustain foam stability; a bioderived, ecologically certified polymer for color care; and a low-temperature cleaning enzyme. Together, these components create a durable foam layer that envelops garments throughout the wash cycle, minimizing direct fabric-on-fabric contact.

Study Design — Two Phases, Four Countries

Study 1 Results — Consistent Across Four Independent Facilities

The first study is particularly valuable precisely because the four institutions used entirely different washing machines (GIRBAU, Bosch, LG, Miele), different water temperatures (20–43°C), different water volumes (27–45 litres), and different wash cycle durations (32–119 minutes). Despite this, the conclusion was uniform across all four sites: detergent B produced significantly lower sFF masses than detergent A.

Mean sFF mass per kg of textile using detergent B was 0.08 / 0.07 / 0.05 / 0.08 g/kg across the four institutions respectively, versus 0.23 / 0.16 / 0.14 / 0.11 g/kg for detergent A — a reduction ranging from 30% to over 90% depending on specific conditions. A linear mixed-effects model applied to all 196 data points confirmed that detergent type was the single most statistically significant factor influencing sFF emissions, outweighing even water temperature and wash duration.

KEY FINDINGS FROM STATISTICAL MODELING

→  Detergent type and detergent mass were the two most significant drivers of sFF emissions (both p < 0.0001)
→  Water temperature and cycle duration showed no statistically significant effect on sFF emissions (both p > 0.05)
→  Full loads (1 kg fabric, 50 g detergent) produced lower sFFs per textile than single loads (130 g fabric, 15 g detergent) — suggesting full-load washing is itself a mitigation strategy
→  Jersey fabrics (staple carded yarn) shed more fibers than taffeta and mikado (continuous filament yarn) under full-load conditions

Study 2 Results — The Role of the Tumble Dryer

The second study added machine drying to the workflow, reflecting real-world consumer laundering practice. Whole garments made from polyester-cotton blends (four garment types, ranging from 20% to 80% polyester) were washed and then dried, while fiber fragments were collected from three sources: washing machine effluent, the dryer lint trap, and a secondary filter on the dryer exhaust duct.

For washing: detergent B produced approximately 39% fewer fiber fragments captured on the nylon filter versus detergent A (0.27 vs. 0.45 g/kg). When including mass from the coarse sieve, the reduction was 25% (0.37 vs. 0.50 g/kg; Wilcoxon test, p = 0.02).

For drying: this produced the study's most striking finding. Fiber fragment masses recovered from the dryer did not differ significantly between the two detergents (0.50 vs. 0.49 g/kg). This means detergent B reduces emissions during washing, but has no influence on fiber loss during drying — a purely thermo-mechanical process independent of any antecedent detergent chemistry. Nevertheless, because washing and drying are sequential, the savings from the wash phase propagated through to yield an overall 12% reduction (0.87 vs. 0.99 g/kg; p = 0.02) across the full laundry cycle.

"The mass of fiber fragments released from the dryer averaged 137% of that released from the washing machine — meaning tumble drying is an even greater pathway for microplastic fiber pollution than washing." — Calculated from Study 2 results, Li et al. 2025

Limitations and Future Research Directions

The authors are transparent about the study's limitations: only a single conventional detergent was used for comparison — the results have not yet been extended to other brands or formulations. Furthermore, all textiles and garments used were new. Prior research has demonstrated that the majority of sFF release occurs in the first few wash cycles as fibers loosened during manufacturing are flushed out, with emission rates stabilizing after 8–10 cycles. The effectiveness of detergent B across repeated successive washing cycles therefore remains to be established.

There is also no universally accepted standardized methodology for quantifying sFF release from domestic laundering. The Microfiber Consortium and ISO have issued test protocols (ISO 4484–1:2023; AATCC TM212), but these do not fully replicate real-world domestic washing conditions.

Policy Implications and Opportunities for Vietnam's Chemical Industry

Editorial Note: Detergent B in this study was developed by BASF and Inditex and is commercialized as 'The Laundry' through Zara Home. The entire study was funded by Inditex. The authors declare no financial conflicts of interest. The research underwent independent peer review and was published in Cleaner Materials (Elsevier; CiteScore 2024: 7.4).

Original article: Dong Li et al., 'Detergent-mediated reduction of fiber fragment emissions during conventional machine laundering of textiles and garments,' Cleaner Materials, Vol. 15 (2025), 100303. DOI: 10.1016/j.clema.2025.100303. Received: 12 Sep 2024 · Accepted: 1 Mar 2025 · Published online: 4 Mar 2025.