This story is adapted from one5c‘s complete guide to plastic pollution. Check out the whole thing here, or read more about bioplastics here.
The plastic products that we can hardly live without have a dirty secret: More than 99% are made from fossil fuel sources. One increasingly common salve to our petroleum-fueled pollution problem? Using less harmful ingredients to make our mountains of stuff.
Enter bioplastics, also known as biobased polymers. On the surface, these materials seem like a fabulous deal. They’re from plants like corn, sugarcane, wheat, and potatoes or even recycled food waste like banana peels and coffee grounds; they break down relatively easily; and can also handle many of the same jobs as their petroleum-derived counterparts. Manufacturing them also generates fewer emissions.
But (and it’s a big “but) just because a company throws a little green leaf or image of the planet on your disposable fork or coffee cup or plastic bag, it doesn’t necessarily mean it’s benign. The simple truth is that plant-based plastics don’t always meet their high expectations, and are ripe for greenwashing. Amid consumer appetites for greener wares, the market for these alternative polymers is growing. Here’s what you need to know to avoid falling into a marketing trap.
1. Bioplastic is plastic
Bioplastics can be great 1:1 swaps for conventional plastics because, chemically speaking, they’re pretty close. To make petroleum-based plastics, factories force monomers to bond together into polymers by applying heat, pressure, and chemical reaction-spurring compounds called catalysts.
The process works somewhat similarly for nature-based monomers. For example, polylactic acid (street name PLA, which makes up around 20% of bioplastics) starts as lactic acid derived from fermenting sugar from plants like corn. There are also “bio” versions of other widely used polymers like polyethylene and polypropylene, which you commonly see in packaging, and polyethylene terephthalate, which is the ubiquitous PET that’s in your water bottles. Bio-polyethylene in particular is the product of dehydrating ethanol derived from sugarcane, sugar beets, and wheat grain.
2. Which means it still has the same problems
Because they are so similar, bioplastics face a lot of similar environmental stumbling blocks as petrol-derived versions: namely microplastics, toxicity, and recyclability. In some cases, they can be worse than their counterparts. One 2023 study in the Chemical Engineering Journal, for instance, found that a PLA-lined cup released 3.6 times higher levels of microplastic than a similar product made with regular polyethylene. Also, a 2020 analysis found that starch-based bioplastics have especially high contents of chemical additives linked to hormone disruption.
And, just like conventional plastics, not every type of bioplastic can safely go into the blue recycling bin. BioPET and BioPE can mingle with other recyclables, as long as your local facility is set up to accept them; most recyclers accept plastic with a #1 or #2 symbol. Bioplastic or not, “wishcycling”—that is, putting items that you hope are recyclable but may not be in the bin—can contaminate the recycling batch and mess up the overall process.
3. ‘Biodegradable’ isn’t what it seems
Bioplastics are marketed as biodegradable and sometimes compostable, which is a gray area. “Biodegradable” is really an umbrella term that means that microorganisms can break an item down into smaller and smaller parts, like carbon dioxide, water, methane, and even compost. So, yes, just about everything on Earth fits that definition—the question is by what means and into what.
In the case of bioplastics, labeling something as “compostable” can be misleading. Most products made from compostable bioplastics, like cups or bottles, require extremely high temperatures to break down, which means not a lot’s gonna happen in a backyard compost pile. Instead, they need to go to an industrial facility, which only a few cities have right now.
If a piece of bioplastic winds up in the landfill, it will also biodegrade. But in these dense, oxygen-free environments, that’s not a good thing. Tiny organisms break down the material, a process that releases methane, a greenhouse gas that is at least 28 times more effective at trapping heat in the atmosphere than carbon dioxide. And don’t forget all those chemicals and microplastics.
4. Many ‘bioplastics’ still contain fossil fuels
Seeing a “bioplastic” label on a product or website isn’t a guarantee that there are no fossil fuel sources in the bottle or cup. There’s no official federal regulation or definition of the term, which means some companies slap the label “bioplastic” onto materials that don’t come entirely from plant-based sources. For instance, some companies market polybutylene adipate terephthalate (PBAT), which is often used to make packaging and cutlery, as bioplastic or biodegradable plastic because it breaks down more easily than other types of plastic. By some accounts, packaging and materials made from bioplastic may still contain as much as 80% fossil fuel plastic, and the popular NaturALL bottle used by Pepsi and Nestle is only 30% biobased.
5. The best thing you can do is avoid plastic. Period.
The other big catch with bioplastics is that they’re not that great. They can’t compete with their fossil fuel–derived cousins in terms of price and accessibility, and they’re expensive to manufacture, says Rafael Auras, a professor specializing in packaging sustainability at Michigan State University. Bioplastic production can cost five to 10 times more than fossil fuel–derived processes. The materials also aren’t typically as strong, and some of the most sustainable bioplastics, like those made from starch or plant protein, have a limited shelf life, Atanu Biswas, a chemist at the National Center for Agricultural Utilization Research, points out, because they’re a little too good at breaking down.
To make a real impact on plastic pollution, trading fossil fuel plastics for biobased ones is at best a half-measure—as long as you know and accept the caveats. The absolute best thing to do is avoid single-use products in our day-to-day lives as much as possible, before they make their way to landfills, oceans, and our bodies. Luckily, we rounded up a list of 15 ways to dial your plastic use back.