cigarette butt on a sandy beach Cigarette butts cause problems in any ecosystem they invade. (Photo: ucubestudio/Shutterstock)

Plastics straws have been public enemy No. 1 for a while now, as companies, cities and even a couple of states have made strides to ban them. But there's a bigger villain we've been ignoring.

Cigarette butts — those pesky and toxic leftover remnants — contain plastic in the filters that isn't biodegradable. These butts easily find their way in our waterways and our greenspace simply because they're cast aside so indiscriminately. Getting rid of cigarette butts may help the health of humans, our oceans and our planet all at the same time.

"It's ... a major contaminant, with all that plastic waste. It seems like a no-brainer to me that we can’t continue to allow this," Thomas Novotny, a professor of public health at San Diego State University and the CEO of Cigarette Butt Pollution Project, told NBC News.

Bad for us, bad for the planet

a cart full of cigarette butts at a global climate strike in Italy A sign at a global climate strike in Italy sums it up. (Photo: lara martone/Shutterstock)

Some 5.5 trillion cigarettes are produced each year around the world, and about 98% contain filters made of cellulose acetate, according to the Cigarette Butt Pollution Project. Cellulose acetate can take a decade or longer to break down under ultraviolet light, which in turn disperses the toxic plastic into smaller bits.

We know cigarettes aren't good for us. The filters ostensibly reduce the amount of tar a smoker inhales when taking a drag. But filters force smokers to inhale more deeply to get the same sensation from the tar and nicotine. The result is the illusion of a healthier version of a bad-for-you product. And Novotny agrees: "It's pretty clear there is no health benefit from filters. They are just a marketing tool. And they make it easier for people to smoke."

Filters also further increase the presence of plastics in our environment. For the last three decades, cigarette butts have been the most commonly found item during the Ocean Conservancy's annual international coastal cleanup project; during the 2018 cleanup campaign, volunteers found roughly 2.4 million of them on beaches. (By comparison, 643,000 plastic straws and stirrers were found.)

They're bad for plants, too

Cigarette butt lies by a purple flower in meadow A cigarette butt looks out of place near a flower in a meadow. New research out of England reveals they have a bigger environmental impact on plants than smokers think. (Photo: Egeris/Shutterstock)

Butts are problematic no matter where they end up, and not just because they're unsightly. Research led by Anglia Ruskin University in Cambridge, England, found that cigarette butts impede plants' development. The study, published in Exotoxicology and Environmental Safety, found that tossed butts reduced germination of ryegrass by 10 percent and white clover by 27 percent. The study went on to look at root-to-shoot ratio and discovered a negative influence there as well.

The numbers remained constant for regular and menthol cigarettes, and interestingly, for smoked, partially smoked and unsmoked cigarettes.

It's a cultural problem

Seemingly aware of the litter problem, cigarette companies have long attempted to help smokers dispose of the cigarettes butts, by sponsoring anti-litter campaigns and distributing permanent and disposable ashtrays. R.J. Reynolds Tobacco Co. once distributed disposable pouches for smokers to discard their butts in.

Smokers have a hard time ditching the butt-flicking behavior, however. NBC News cited industry focus groups that found smokers thought ashtrays were too disgusting to use, believed filters were biodegradable, and thought butts needed to be put on the ground. One group even said that flicking the butt into the environment was simply "a natural extension of the defiant/rebellious smoking ritual."

Various groups have been working to stem the cigarette butt tide. The Cigarette Butt Pollution Project has a list of policy positions, including putting the onus of butt cleanup on the tobacco companies, enacting a ban on disposable filters, litigating the environmental harm cigarettes do, and the overall elimination of smoking. The anti-cigarette campaign, The Truth, is also gunning for cigarette butts, as you can see in the video above.

Legislators have struggled to get filters banned, and littering laws have always been difficult to enforce. Novotny told NBC News that any serious movement against filters will likely require the American Cancer Society, the American Lung Association and the American Heart Association to get involved, just as they have regarding the dangers of cigarettes on human health.

Of course, environmental health is human health; it's just a matter of getting everyone to see it that way.

Editor's note: This story has been updated since it was first published in August 2018.

Cigarette butts are the most pervasive man-made pollutant
These plastic filters far surpass plastic straws in coastal cleanup tallies and they're toxic on land, too.