America's got a butt problem. A big one.

We're talking about cigarette butts — the shriveled little bits of flicked cigs that are creating a not-so-little problem for our environment. "World No Tobacco" day, which is on May 31, prompted us to examine smoking's environmental impact.

What's that? You just saw a cigarette butt sail from a car window? Lodged in a sidewalk crack? Chances are you're not alone; cigarette butts are far and away the most littered item in the world, with roughly 4.5 trillion being tossed each year. The lobbying group American for Nonsmokers' Rights (ANR) reported that 1.69 billion pounds of butts ended up as toxic waste last year. That's like the weight of 177,895 endangered African elephants, or 555,555 Toyota Prius automobiles, or...well, you get the idea. That's a lot of junk in our collective trunk.

But cigarette butts aren't just a punch line for bad puns — they present a serious hazard to our natural world.

The butt itself is comprised of two parts: A plastic filter and the remnants of the used tobacco. While the leftover tobacco is by definition biodegradable, the filters are made from a plastic called cellulose acetate, a compound that eventually breaks down but never disappears. Ever. Combine that with the roughly 4,000 chemicals found in cigarettes, and you've got the recipe for a pretty awful eco-aftertaste.

This doesn't stop our wildlife from sampling the local cuisine. Birds and dogs often pick at the bite-sized waste, and marine animals like fish can ingest cigarette butts that wash into nearby lakes, rivers, and oceans. If the poisons don't claim their lives first, a predator or a commercial fishery might, setting into motion a complexly destructive cycle in our food chain.

Toxins: They're what's for dinner.

This waste tears at the people-planet relationship in other ways, too; fires caused by cigarettes take the lives of more than 900 people in the U.S. every year. These fires amount to nearly $6 billion in annual human and property costs. Needless to say, it's costly to have large (numbers of) butts.

So what's a concerned derrière dissenter to do? Fortunately, there are many nonprofit organizations designed to raise public awareness of cigarette butt waste. You can find a local Sierra Club volunteer chapter that's committed to keeping our streets, beaches, and oceans clean.

The easiest way to make a difference? Don't litter in the first place — find a designated waste bin for your cigarette. Even better, don a pair of work gloves and organize a trash pick-up day with your friends. Discarded cigarettes might be small, but only our individual efforts will keep the issue from getting any bigger.

And, trust us: That's a big but.