Some count long stretches of powdery white sand, others are fringed by dramatic cliffs. But no matter the beach or its location, there’s little escape from the blight that plagues many of them: cigarette butts. Spain’s nearly 5,000 miles of coastline are no exception. “On beaches where smoking is allowed, unfortunately cigarette butts continue to rank as the most found waste product and the one with the most significant impact,” says Inés Sabanés a Spanish lawmaker with the Más País–Equo governing coalition. The coalition was the driving force behind a new legal framework that came into effect in April, which allows local councils to ban smoking on their beaches and impose fines of up to €2,000 (£1,700). The move has catapulted Spain to the forefront of countries seeking to crack down on what the UN describes as “the most discarded waste item worldwide”: the estimated 4.5tn cigarette butts littered each year. Whether flicked on to beaches, tossed in parks or dropped on to streets, many of the tiny, lightweight butts end up in bodies of water, swept there by rainfall and storm water systems. Few are aware of their persistent and potentially harmful effects on marine environments, says Kari Martin of New Jersey-based Clean Ocean Action. “It is part of the plastic problem,” said Martin. “Many people don’t know that the cigarette filters themselves are made out of plastic fibres.” These plastic filters – estimated to be a component in more than 90% of commercial cigarettes – are made of cellulose acetate. “Plastics don’t break down over time, they photodegrade, which means that the light breaks them into smaller pieces but they don’t eventually go away,” says Martin. As these bits of plastic and microplastic are carried along coastlines and waterways, there is little to prevent them from becoming food for animals. “The cigarette butts themselves look like little fish,” said Martin, citing a photo snapped on a Florida beach in 2019 that showed a Black Skimmer gingerly feeding a cigarette butt to its chick. In an ocean brimming with plastic litter, cigarette butts stand out as a particularly potent form of waste, said Mitch Silverstein, the policy coordinator for the San Diego chapter of the ocean conservation organisation Surfrider. “They’re the No 1 most littered item in the world,” said Silverstein. “They’re made of non-biodegradable plastic and full of hazardous waste that harms both the Earth and the ocean.” Tobacco smoke contains more than 7,000 identified chemicals, including at least 70 that are known to cause cancer in humans and animals. Among those who have long warned of the impact these chemicals could have on marine life is the World Health Organization. “This toxic waste ends up on our streets, in our drains and in our water,” the organisation noted in a 2017 report. “Research has shown that harmful chemicals leached from discarded butts, which include nicotine, arsenic and heavy metals, can be acutely toxic to aquatic organisms.” A 2011 study by San Diego State University suggested that the chemicals leached from one smoked cigarette butt were capable of killing half of the fish present in a one-litre bucket of water, while researchers at the UK’s Anglia Ruskin University found cigarette butts significantly hindered the growth of terrestrial plants. Others have delved into the longer-term effects of the chemicals in cigarette butts, finding that after 28 days of exposure freshwater rainbow trout ended up weighing less while Mediterranean mussels absorbed 22 compounds, including some classified as potentially toxic to humans or wildlife. The results hint at the broad consequences that this often-overlooked waste product could pose for those who rely on fishing for their livelihood as well as anyone who consumes seafood products. “Humans are the top of the food chain – we pollute the ocean and then use it as a source of sustenance,” said Silverstein. “We’re just eating our trash, we’re eating our own toxins.” After years of nudging smokers to responsibly dispose of cigarette butts, Silverstein has shifted his focus in recent years. “We were trying to mop up the floor rather than turn off the taps,” he said. “We need to point the finger at the real source of the problem. Tobacco companies need to stop putting single-use plastic filters on the trillions of cigarettes they produce.” A ban on cigarette filters is a logical next step after reviews, carried out by bodies that include the US surgeon general and the National Cancer Institute, suggested cigarette filters are little more than a marketing tool, said Tom Novotny a professor emeritus of public health at San Diego State University. “One might say, well, doesn’t the filter do some good?” Novotny said. “No it doesn’t.” Studies have instead linked filters to the deeper inhalation of smoke, potentially increasing the risk of an aggressive form of cancer known as lung adenocarcinoma, he adds. Novotny’s view is backed by the WHO, who recently said that the plastic filters – added to the cigarettes in the 1950s to assuage fears over the emerging links between cancer and smoking – have done little to protect smokers. “As we now know, claims that filtered cigarettes were ‘healthier’ were fraudulent,” the organization noted in 2017. “The only thing filters may have done is make smoking easier and less harsh, increasing both the risk of addiction for smokers and the overall burden of the non-biodegradable and toxic cellulose acetate filters in our environment.” The years of mounting evidence against cigarette filters have propelled Novotny to become one of the leading voices in the push to ban single-use cigarette filters in the state of California. “There’s so much more concern about plastics these days,” he said. “And this one particular kind of plastic has no function except to sell cigarettes which kill people and cost our health care system a lot of money. So why do we want to even tolerate it?” When contacted by the Guardian, tobacco companies Philip Morris International and Imperial Brands said they were exploring alternatives to plastic filters. “We also intend to tackle the issue at the source, continuously working to replace the plastic in filters with better, more sustainable alternatives,” a spokesperson for Philip Morris said in a statement. Imperial Brands, previously known as Imperial Tobacco Group, said it was testing paper filter alternatives in Germany and Finland. “Consumer acceptance and emissions regulation have meant that we are yet to find an adequate alternative substitute for the traditional cigarette filter,” it added. British American Tobacco said it was working on “a number of initiatives in different parts of the world, including public-awareness raising initiatives, that have been shown to be effective in reducing cigarette butt littering”. The statements did not address the Guardian’s question on the health impacts of cigarette filters. Despite years of campaigning, three attempts in California to ban the butt have made little progress. Instead, inroads have been carved out at the local level; San Francisco began adding a “litter abatement fee” on packs of cigarettes in 2010 while last year Beverly Hills and Manhattan Beach banned the sale of all tobacco products within their city limits. Others have followed suit. France’s environment minister said last year the country was set to charge tobacco manufacturers €80m annually to clean up the estimated 23bn cigarette butts littered each year across the country while governments in the Gambia, Chad and Benin have imposed environmental taxes of up to 4% on packs of cigarettes. Some companies have been more creative; earlier this year a Swedish firm said it was recruiting crows for a pilot project aimed at picking up cigarette butts. The efforts to address plastic cigarette filters, while crucial, is only part of the vast environmental impact of smoking, say environmentalists. As the use of e-cigarettes swells in the US, so has the presence of discarded vape pens and plastic cartridges along seashores. “People discard them just as easily as cigarette butts,” said Martin of Clean Ocean Action. The experience in Spain – where in recent years 550 of the country’s more than 3,000 beaches have moved to ban smoking – suggesting that progress in addressing the issue is unlikely to be linear. In July, after nearly two years of prohibiting smoking on all of its beaches as part of its measures to contain Covid-19, the northern region of Cantabria said smokers would once again be allowed to light up along its coastlines. “It’s a pity,” said Sabanés, the Spanish lawmaker. “It’s always like that. You take a step forward, but of course you always have to keep on fighting.”