Just a few short years ago, extreme heat caused by climate change was a futuristic projection. Now, it has arrived as a grave threat to workers up and down fashion supply chains, hampering the industry’s ability to function.

A rising number of dangerously hot days are hitting fashion factories, especially those concentrated in South and Southeast Asia, where extreme heat is most acute. Sweltering temperatures are affecting everything from the number of workers out sick or fainting on the factory floor. It is overwhelming power grids and diminishing workers’ capacities to think clearly or sew with precision.

As outlined in a report by New York University’s Stern Business School this week, it’s heat stress — and not just climate change at large — that’s emerging as one of the biggest threats to fashion’s workforce and to the resilience of the entire industry. The findings show that heat waves in India are already disrupting production, driving up absenteeism, and reducing product quality. In 2024, when temperatures in the garment-producing country rose above 104°F for days on end, workers experienced fainting spells, urinary tract infections, rashes, and worsening period cramps.

The report offers a clear playbook for brands: establish mandatory heat-risk data collection and reporting, develop standalone policies on extreme heat adaptation, and support deeper investments in cooling and ventilation in factories.

But manufacturers cannot afford to wait for brands to take action. Faced with the reality of hot temperatures, many forward-thinking manufacturers have, over the last few years, begun to rethink their factory designs and puzzle through how to keep their workforce cool, says Gauri Sharma, director of strategy and engagement at the Fashion Producer Collective (FPC), a manufacturer-led sustainability think tank. “Everyone’s trying to figure out what works for them, preparing guidance, making changes on the shop floor, and upgrading existing infrastructure installation,” says Sharma.

Now, manufacturer-led efforts are becoming more organized and vocal. FPC members have met regularly over the past six weeks to share challenges and solutions behind closed doors. Vogue Business was granted special access to some of these conversations, the findings from which are shared below. Further case studies, gathered by researchers in India, Vietnam, and Cambodia, point to examples of factories adapting on a budget (they say industry financing has not caught up to this problem yet, instead focusing its attention on reducing greenhouse gas emissions).

Some of the solutions proposed by manufacturers offer a glimpse into a climate-adapted future for fashion. But these solutions will only go so far. Tackling heat stress will require the whole industry coming together to take action.

The model factory

Garment factories weren’t designed with 120-degree heat in mind. Most are simple corrugated or concrete warehouses. Some are shed-style buildings that are open on the sides. Many are packed with humans and heat-generating machines like boilers, steam irons, and dryers, which can push indoor temperatures even higher than those outside. Air conditioning is a rarity.

Major Hong Kong-based garment manufacturer Epic Group put the comfort of its workforce first in dreaming up its new 33-acre campus, Trimetro, a net-zero model factory in Odisha, India, which employs 10,000 workers and is capable of churning out 20 million garments per year, according to VP of sustainability Vidhura Ralapanawe. It’s capable of operating smoothly in temperatures of 120°F or more. “We are really focusing on conditions of the people inside and outside the factory, and making it central to design,” he says.

To keep the factory cool as outdoor temperatures soar, even in one of the world’s most heat-stressed countries, Trimetro’s buildings and windows are oriented away from direct sunlight, roofs, and walls are wrapped in high-performance insulation that reduces the demand for cooling, and the surrounding grounds are shaded with native plants and trees that reduce outdoor temperatures by nearly 18°F in what Ralapanawe calls “microclimate management”.

Ralapanawe is clear-eyed that Trimetro is setting a standard that most manufacturers can’t meet, at least not without huge investment. The company received a low-cost $100 million loan from the International Finance Corporation for the build-out.

Still, Trimetro is inspiring the industry and the rest of its company to imagine how fashion supply chains may look in the future. “There have been so many learnings on how we design air conditioning, how we design buildings, how we design the surroundings, how we design systems that are interconnected,” he says, noting that Epic has already adopted Trimetro’s high-grade insulation in its other facilities.

Starting with the basics

While Epic shows what a purpose-built factory of the future can look like, there are more basic and affordable steps that can be taken today. Within the FPC working group, recent conversations have turned to how manufacturers can effectively log temperatures and develop internal protocols, says Sharma. “People are trying to adjust to these temperatures, and to make protocols and make guidelines.”

Jimmy Summers, VP of environment, health, safety and sustainability at Elevate, a large Tier 2 company, is setting the example. His company first developed a standalone internal heat-stress protocol in 2018, as operating dye houses in hot countries like Sri Lanka and Cambodia made indoor temperatures an unavoidable issue. “We operate dye houses in some very hot locations, and dye houses are the hottest places, I would say, in textile manufacturing,” says Summers.

Elevate set a company temperature threshold of 88°F, past which its managers launch into a heat-stress action plan, which includes rescheduling heat-generating processes for the coolest parts of the day, switching to power tools for high-exertion work, and reminding its workforce to hydrate more and take more breaks. The company also regularly measures indoor temperatures, which, as the NYU Stern report states, is the foundation of any industry approach to heat stress.

Industry guidance may also require wet bulb measurement, where manufacturers measure humidity, radiant heat, and air movement and wind, as well as ambient temperature. In the meantime, industry experts say less sophisticated tools can be effective to get started. “You could start easily just by having cheap thermometers and logging to see what your indoor air temperatures and humidity levels are throughout a day and throughout a year,” says Sarah Krasley, a visiting fellow at Cornell’s ILR Global Labor Institute and author of a January report on heat stress. It’s important to measure different areas around the factory, Krasley adds, as a spot near a boiler will be much warmer than a sewing line.

The industry is currently working to standardize heat index thresholds in factories. In April, the American Apparel and Footwear Association (AAFA) published its first voluntary heat-stress guidance for members. VP Nate Herman says the group is working urgently to develop implementation guidance, as well as a standard survey for suppliers “to better understand the daily obstacles they’re facing and identify the key resources they need”.

Trial and error at a northern India knitwear factory

Nudged by oppressive heat and lost productivity, some manufacturers are already moving beyond workplace protocols to modifying factory walls, roofs, and systems. According to the NYU Stern report, structural upgrades and improved ventilation are some of the most effective strategies for reducing indoor temperatures in garment and textile factories. But retrofitting these measures is much more complicated than building climate-adapted factories from scratch.

Without clear industry guidance, factories are taking a phased approach, trying out cheaper solutions first to see what works and then layering up solutions. Researcher Lucy Siers, who authored the NYU report, offers Poppy’s Knitwear in India as a template for a layered approach.

The company, whose workforce was flagging after heat waves in 2022 and 2024, first installed evaporative coolers, which use water to cool the air in the factory walls. Hoping for better results, coolers were also added to the ceiling, helping to circulate the chilled air. From there, Poppy’s Knitwear installed heat-reflective roofing to prevent the sun’s rays from pulsing through the roof and false ceilings to create a gap between the hot air circulating and workers down below, while relocating high-heat equipment like pressing machines closer to windows to improve ventilation.

When Siers visited in September 2025, these heat-mitigation upgrades had been completed in five of the factor’'s eight production units. Even before the hottest part of the year, the changes had reduced indoor temperatures by roughly 2-3°C, worker absenteeism was down, and productivity was up.

Factories are taking on this work because it’s necessary. In some places, like India, outdoor temperatures during heat waves are lethal. And they’re discovering that even modest investments in cooling can help retain their workforce and avoid huge slowdowns in productivity. Considering many workers’ homes are sweltering, a cool workplace is becoming an edge.

At An Giang Samho, an 11,000-worker footwear factory about five hours from Ho Chi Minh City, Vietnam, longer summers and hotter nights forced the factory management to seek new ways to cool the building. But the facility’s open-sided shed design is very difficult to cool, and they can’t simply close up the sides, because shoemaking involves processes like gluing and printing, so they have to be mindful of chemicals and fumes circulating.

As a workaround, Samho installed large exhaust fans powered by renewable energy, and placed smaller fans at worker stations. It also started diligently measuring the temperatures in the factory to understand which areas needed the most attention. From there, the company worked with solar vendor SkyX Solar to add panels and insulation to the roof — interventions that brought the indoor temperature down by 5.4°F. Finally, ice machines were installed all around the factory for the workforce, which union representatives say was especially meaningful because it felt like it was purely done to increase their comfort, not just to be compliant with buyer demands. In her research, Krasley also visited Sabrina Garments, a 6,200-worker apparel factory in Cambodia, where management had invested under $250,000 to install evaporative “water curtains” and large exhaust fans to keep temperatures comfortable, even as outdoor temperatures climbed above 104°F.

Krasley said she was surprised to learn that factories felt like these modest investments came with a reliable return, as it helped keep workers from looking for other jobs and boosted productivity.

Aligning standards and incentives

Even the most innovative factory can only go so far on its own. Whether it’s installing insulation, experimenting with cooling technologies, or redesigning production floors, manufacturers ultimately operate within a supply chain shaped by brand requirements, delivery deadlines, and razor-thin margins. As heat waves become more frequent, many say the next phase of adaptation will require the rest of the industry to move with them.

“Many suppliers have sort of reached the limit, both financially, but also in terms of expertise and know-how of what they are able to do without buyer engagement,” says Siers.

Buyer support will be essential. That doesn’t necessarily mean funding expensive retrofits or new buildings, at least not yet. Immediate help could come through purchasing practices that acknowledge the realities of extreme heat. Siers says that brands should work with suppliers on production planning, allowing additional flexibility during predictable periods of extreme heat. “Responsible purchasing practices, such as fair delivery timelines and ensuring that planning is somewhat collaborative, so that suppliers do have the capacity to deliver,” can make it easier for factories to implement heat protections, she says.

Finally, while manufacturers welcome a coordinated approach across the industry to heat stress, they say solutions will need to differ from region to region and factory, based on what’s effective and feasible. “It is so contextual,” says FPC’s Sharma. “It depends on where you’re located, your heat risk, what sort of factory you are, and what sort of budget you have.”