Compostable Dog Poop Bags Aren’t Really That Compostable

This story was produced in partnership with the Pulitzer Center’s Ocean Reporting Network.

In the United States, one of the best-selling dog waste bags on Amazon is compostable. So far, so green. Paying slightly more to clean up after fido in an earth-friendly way casts a double halo—you can be a responsible dog parent while making a point to avoid plastic’s myriad sins. And now that an increasing number of cities are implementing curbside composting programs, add a third halo: by diverting organic waste from landfill, we can also cut down on planet-warming methane emissions.

Hold on to those halos. In most cases, spending more on that compostable dog poop bag is a meaningless gesture. You might as well be throwing your green-premium cash in the garbage. Because, technically, you are. In the U.S., industrial composting facilities won’t accept dog waste. So those expensively swathed bundles end up in landfill anyway, where it could take anywhere from 75 to 400 years, or more, to decompose. Nor are they necessarily plastic-free: many compostable bags are made from fossil fuels treated with chemicals designed to help them biodegrade more quickly—and potentially break down into microplastics. They may not even be compostable: Biodegradable Products Institute (BPI), which sets and certifies composability standards for North America, no longer certifies dog waste bags for the U.S. market because it’s pointless to set standards for something that can’t be used as intended.

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Not every bag is worthless. U.S. readers who deposit their bagged dog waste in their back-yard compost can rest easy. So too can Canadians, in whose country many municipal composting facilities accept, even encourage, dropping off pet waste alongside household food scraps. Visitors to the handful of urban dog parks that have a dedicated composting program can also use their green-tinted bags with abandon.

But for everyone else, compostable poop bags are just another example of how corporations continue to shift the responsibility for effective climate action onto individuals, rather than adopting the kind of systemic change necessary to make a real impact. As long as consumers believe that only they can fight climate change—by flying less, recycling more, or buying greener products—the airlines, manufacturers, and fossil fuel companies whose business-as-usual activities are driving global warming the most won’t have to do anything at all.

The issue is bigger than dog waste, of course.

Consumer awareness of plastic’s outsize impact on our climate and environment is driving demand for more compostable materials, especially in food service, where compostable plates, bowls, forks, wrappers, and straws have become the mark of a socially responsible company. The problem is that there are more restaurants and shops providing compostable packaging than there are facilities that can accept it.

Read more: There’s Almost No Research on the Health Impact of Plastic Chemicals in the Global South

Of the approximately 200 industrial composting facilities in the U.S. that accept food waste, only 142 take compostable food-contact packaging, according to a new survey conducted by composting clearing house BioCycle and the Composting Consortium (schools, resorts, health care centers, correctional facilities, and corporate campuses that run their own composting programs were not part of the survey). The reasons vary. Some facilities say, with justification, that they can’t tell the difference between conventional and compostable plastics and they don’t want to risk contamination. Others sell their compost to USDA certified organic farms, which, for the moment at least, do not accept packaging as acceptable organic feedstock.

As a result, the U.S. is producing more compostable materials than it can actually compost, says BioCycle’s editor and publisher, Nora Goldstein. Your local coffee shop might be trying to do the right thing when lattes come in compostable cups, but if there isn’t a nearby facility that accepts them, chances are they will end up in the garbage anyway, where they could cause even more climate damage than conventional plastic. In a well-maintained composting facility, bacteria use oxygen to break organic materials down into carbon. In a landfill’s low oxygen environment, that material creates methane as it decomposes, a greenhouse gas 25 times more potent than carbon when it comes to trapping heat in the atmosphere.

New York City is now doing its part to minimize methane emissions from landfill by making food waste composting mandatory by 2025. In the meantime, voluntary curbside collection is rolling out on a borough-by-borough basis; Brooklyn started this month, with Manhattan scheduled for fall of 2024. At least nine states, including California and Washington, have passed similar laws, with Denver, Boston, Chicago, and Washington, D.C., offering voluntary curbside collection or running pilot programs. Compostable food packaging will be accepted in most of them. Pet waste, whether or not it’s in a compostable bag, will not. Nor will compostable diapers or compostable sanitary products, for that matter.

That’s a lost opportunity, says Goldstein. New York City alone has some 600,000 canine residents. At the Environmental Protection Agency’s estimated average of 0.75 pounds of waste per dog, per day, that comes to some 82,125 tons of poop heading to New York landfills every year. That would produce the equivalent of 112,018,500 pounds of CO2 emissions, about the same as 11,046 gasoline powered cars driving for a year. Technically speaking, dog poop (as well as compostable diapers and sanitary products) would break down just as well as food scraps at a well-managed composting facility.

More often than not it’s zoning regulations and concerns about worker exposure to potential biohazards that get in the way, says Goldstein. “Pet waste truly is compostable. If the bag it is packaged in is also compostable, you could really solve a landfill problem.” That said, she doesn’t buy compostable pet waste bags herself. Her town doesn’t offer municipal composting, so there is no point in spending more on a greener product, she says. “If it’s going to landfill, for all intents and purposes, it is a plastic bag.” Even composter-in-chief Rhodes Yepsen, BPI’s executive director, uses plastic poop bags.

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But not everyone is willing to give them up just yet. Marine ecologist Rachel Coppock buys them even though her research at the United Kingdom’s Plymouth Marine Laboratory indicates that they may not break down well in ocean environments. A work colleague in New Jersey, who has access to curbside composting services, uses them to pick up after her dog, flushes the waste down the toilet when she gets home, and then composts the bag with her food scraps. “Even non-composters have taken a positive step by not buying plastic bags,” she tells me. Kind of. One popular option on Amazon proclaims that its Doggy Do Good compostable pet waste bags are “38% vegetable-based,” which begs the question of what, exactly, is in the remaining 62%. (The company did not respond to an emailed query).

Many people probably buy them because the earth-friendly packaging carries an implicit promise to do better for the environment, at just a few cents more per roll. Despite the fact that the folks at BioCycle and BPI tell me not to waste my money, I buy them too. Not because I think my self-imposed green tax will prod producers to come up with more plastic-free, compostable solutions, though that would be nice. I buy them because they come wrapped around a small cardboard tube that my dog loves to chew. At least when she’s done, I can throw that in the compost.