Ihave been hesitating for months. The wetsuit I swim in every week to keep me toasty warm in the winter and safe from jellyfish stings in the summer is riddled with holes. Yet I can’t bring myself to buy a new one because I’ve learned that comfortable, flexible and insulating neoprene is manufactured using some of the most toxic chemicals on the planet. Neoprene, a synthetic foamed rubber, is made from the petrochemical compound chloroprene. Exposure to chloroprene emissions, produced during the manufacturing process, may increase the risk of cancer, according to the US Environmental Protection Agency (EPA). For the past three years, the film-makers Chris Nelson and Lewis Arnold have been investigating surfing’s links to the human health impacts of chloroprene manufacturing. Their documentary about the world’s toxic addiction to neoprene, The Big Sea, is due to be screened at film festivals worldwide from June. “As surfers, we’ve been consuming neoprene for five decades, but Lewis and I both felt that we hadn’t been told the truth about where [our wetsuits] came from and what they were made of,” Nelson says. As part of the film they travelled to the heavily polluted US region known as Cancer Alley, an area of Louisiana along the Mississippi River where smoke stacks fill the skyline. The air is so toxic here that the cancer risk is 50 times higher than the national average, according to the EPA. The nearby plant run by the Japanese chemical company Denka makes multiple forms of chloroprene, but is not breaking any state laws. While editing the film, Nelson says he received “a spectrum of responses” from wetsuit companies. A few are actively phasing out neoprene, he says, but some have not engaged with the issue at all. The Surf Industry Members Association (SIMA), which represents the surf industry, did not respond to the Guardian’s request for comment but Vipe Desai, its director , disputed the film’s claims in an interview with Wavelength magazine last year. Desai said no brands that the SIMA knew of sourced neoprene from the Louisiana factory. “Some limestone chloroprene rubber chips are indeed sourced via a Denka-owned facility, but in Japan,” he said. “These Japanese chips are not petroleum-based and research shows those facilities are not associated with elevated health risks.” He also said the surf industry had “played a major role in moving away from materials causing harm and will continue to do so”. Denka did not respond to the Guardian’s request for comment but in March it told the publication Chemistry World that it strongly disagreed with the EPA’s assessment of the risks that chloroprene emissions posed to the local community and that this was based on “outdated and erroneous science that the agency released over 12 years ago”. So what alternatives are there? Surf wetsuit companies are increasingly pushing back against neoprene and offering plant-based alternatives. In 2016, Patagonia went neoprene-free and Finisterre followed suit in 2021. The Dutch brand Wallien is using Yulex, a plant-based rubber, or other natural variants for all future production, and Buell in California is doing the same. Last September, Xcel committed to using 100% natural rubber by 2026, the first of the traditional big brands to do so. Meanwhile, Billabong and Decathlon have added single lines of plant-based neoprene wetsuits. Xcel does not label its current neoprene wetsuits – which are made using calcium carbonate mined from limestone rocks, rather than from petrochemicals – as “eco” because the process is still energy-intensive. “That’s a stop on the bridge between neoprene and natural materials,” says Ian Stewart, of Xcel. “We’re moving off limestone as fast as we can.” Meanwhile, surfers are fast becoming more conscious of the environmental and health impacts of their sport. Giles Bristow, chief executive of the ocean charity Surfers Against Sewage, says: “With increasing awareness about where our materials come from, everything from our wetsuits to our boards, I think there will be a market transformation.” Reuse and recycle Last summer, Finisterre launched the world’s first rental service for natural-rubber wetsuits. For £30, customers can rent a £300 Yulex wetsuit for four days. As the company founder, Tom Kay, says, “not owning a product is a better form of consumption”. Of course, there’s still no such thing as a biodegradable wetsuit – even natural-rubber wetsuits often have synthetic outer and inner linings – so Kay’s biggest challenge is working out how to prevent wetsuits ending up in landfills. Thermo-set neoprene, which has been irreversibly hardened by heat, is difficult to recycle as it cannot be melted easily. At its factory in Bulgaria, a wetsuit recycling initiative, Circular Flow, breaks down neoprene waste from thousands of old wetsuits and factory offcuts into a crumb that is remoulded into yoga mats and bags. Currently, wetsuits that Finisterre collects are transformed into changing mats, but Kay’s team are experimenting to see if microbes could break down natural rubber. “We’d like to make more wetsuits from wetsuits – that’s the dream,” he says. Rip Curl has a “recycle your wetsuit” scheme, in association with the US-based recycling company TerraCycle, which has collected more than 20,000 old wetsuits from across the US, Australia, France, Portugal and Spain. Once zips, elastic and metal tags have been removed, the neoprene is processed to make construction materials such as flooring or soft-fall matting used in playgrounds. Paul McCutchion, manager of the Centre for Alternative Materials and Remanufacturing at Exeter University, and his team are testing different wetsuit rubber materials for tensile strength, durability, stretch and thermal insulation. When purchasing his next wetsuit, he says he will opt for brands that take back old wetsuits for some form of recycling, and choose natural rubber or limestone neoprene made from crushed oyster shells. That is because these are a waste product from the food industry, rather than from mined limestone. “With no material having the perfect end-of-life solution,” he says, “the option with the least environmental impact is one that is derived from bio-based materials.” He expects brands to be using water-based glues, instead of solvents, and recycled liner materials at the very least. So, back to my own dilemma. Faced with numerous not-quite-there-yet wetsuit possibilities, I consulted Sophie Hellyer, surfer, cold-water swimmer and environmental activist. “The reality is that most surfers buy a new wetsuit at least every other winter,” she says. But she encourages everyone to look after their current wetsuit instead of rushing to buy a new one. “Rinse it well, dry it out of direct sunlight, get it repaired or stitch it up with Black Witch neoprene adhesive when necessary, and then send to a recycle scheme when it’s no longer fit for purpose.” Perhaps, after all, the most sustainable wetsuit is the one I already own. So for now I’m going to make do, mend and just keep swimming.