The Strait of Hormuz, a Texas lawsuit, a European advertising directive, and a secondhand market growing faster than anyone planned: fast fashion’s structural inputs are on the brink of collapse.
Polyester — the synthetic fiber that makes up the majority of fast fashion’s inventory — is a petroleum derivative. Seventy-six percent of Shein’s total fabric is polyester, per Yale Climate Connections. H&M and Zara’s numbers aren’t far behind. The material’s dominance in the sector was, for decades, a straightforward business decision: polyester is cheap, durable enough for a few wears, and easy to produce at scale. It was also always entirely dependent on the price and availability of oil.
Since February, when the United States and Israel launched military strikes on Iran and commercial shipping through the Strait of Hormuz — the narrow passage through which approximately 20 percent of the world’s oil moves — was largely blocked, that dependency has stopped being invisible. Cargo ships rerouted around the Cape of Good Hope are adding 20 to 25 days to every transit. A surge in fossil fuel prices is now squeezing polyester suppliers and garment manufacturers across India and Bangladesh, according to WWD. In Surat, India’s western textile manufacturing hub, a shortage of cooking gas has driven migrant garment workers out of the city entirely. In Bangladesh, where 90 percent of garment sector energy comes from on-site gas generation, manufacturers facing already razor-thin margins face pressure to cut wherever possible — which, in the garment industry, historically means labor.
The Business and Human Rights Resource Centre has flagged that garment exporters globally are now at risk of increased freight costs, order cancellations, and pressure from buyers to sell goods at discounted prices — all consequences of a disruption that had nothing to do with fashion, and everything to do with the fact that the industry built its business model, at its foundation, on cheap oil.
Fast fashion’s supply chain was built on assumptions that no longer hold
Polyester may be fast fashion’s most visible dependency, but it’s not the only one. The architecture of fast fashion — the $8 dress, the hundreds of new items per week, the disposable season — was built on a set of inputs the industry treated as permanently stable: cheap petroleum, cheap labor, slow-moving regulation, and a consumer base that didn’t ask what was in the fabric.
All of those assumptions are becoming unreliable at once, and not because of any single coordinated effort to challenge them. The Texas Attorney General’s lawsuit against Shein, filed in February and still generating substantial coverage, found shoes with 428 times the permitted level of phthalates, handbags at 153 times the legal threshold for the same chemicals, and jackets with PFAS concentrations up to 3,300 times above allowable limits. The lawsuit wasn’t filed by an environmental organization; it was filed by a state attorney general investigating data privacy violations — the toxic product allegations were essentially a second front that opened in the process.
In Europe, the Empowering Consumers Directive — already transposed into national law across member states and enforceable by September 27 later this year — bans generic environmental claims like “eco-friendly,” “sustainable,” “green,” and “carbon-friendly” unless backed by independently verifiable evidence. Carbon offsetting can no longer be used to claim product neutrality. The directive applies to fashion brands, beauty companies, hotels, and travel platforms equally, and was not written with fast fashion specifically in mind. It simply makes untenable exactly the category of language the sector has most relied on to perform improvement without demonstrating it.
New York’s fashion environmental accountability bill (A4631B) — still alive in the Assembly Consumer Affairs and Protection Committee after equivalent bills stalled in California, Washington, and Massachusetts — would require fashion companies above a revenue threshold to map supply chains from raw material to finished product, conduct environmental due diligence, and set science-aligned climate targets, with fines up to $15,000 per day for non-compliance. The bill’s survival through the 2026 session, according to the National Law Review, positions it for a stronger push in 2027, particularly if EU due diligence requirements create a global standard that U.S. brands are already adapting to.
Why the secondhand market is growing even among shoppers who aren’t trying to be sustainable
While fast fashion’s costs are rising, the alternative is becoming more normalized — and for reasons that have nothing to do with sustainability messaging. ThredUp’s 14th Annual Resale Report, published earlier this month, found the global secondhand market on track to reach $393 billion by 2030, growing twice as fast as the overall apparel market. Fortune reported that luxury resale spending jumped fivefold between Q4 2025 and Q1 2026, while discount secondhand apparel rose more than 4 percent quarter-over-quarter, driven largely by tariff-related price increases on new goods — the same trade dynamics that are compounding Hormuz-related cost pressure on fast fashion manufacturers.
A peer-reviewed study published in ScienceDirect this spring on Gen Z’s secondhand purchase intentions found that value for money, quality, and uniqueness ranked above sustainability as motivations for secondhand shopping. The sector’s growth, in other words, is not contingent on consumers caring about the environment. Demand for secondhand styling services — professionals hired to build wardrobes from pre-owned pieces for clients who don’t have time to source them — is growing alongside purchase numbers.
Fast fashion’s response to all of this — the designer archive collaborations, the sustainability language, the annual ESG reports — addresses the perception problem. It doesn’t address the supply chain’s oil dependency, the chemical load in the garments, or the regulatory environment tightening across three continents. Fast fashion’s competitive advantage was always that it was cheaper than everything else. The model worked for as long as cheap was reliable. It is becoming less reliable as the margins are narrowing from both directions: its own costs are going up, and the cost of opting out is going down.
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