Compostable Mailers: Finding The Best Option

If you are looking for the most eco-friendly mailer possible, you might be struggling to decide between recycled, recyclable, biodegradable, or compostable.

Here's a chart to help.

Bottom line? eCommerce packaging - and the vast majority of packaging - should be designed for recyclability first. Brands should avoid compostable packaging because it is a significant headache for composters focused on taking in as much food and yard waste as possible. However, if 100% compostable is critical to your brand, we strongly recommend that you choose a paper-based mailer such as our 100% Recycled EcoX Mailer, 100% Recycled Kraft Mailer, or 100% Recycled Apparel Mailer.

If the lowest carbon footprint is critical or you need plastic's functional benefits, choose a 100% Recycled Poly Mailer. Compostable poly mailers - even those made with bioplastic - do not address marine plastic pollution and carry many adverse side effects to the planet.

Why isn't a 100% compostable poly mailer made with 100% renewable resources?   Many people think 100% compostable mailers are made with 100% renewable resources. This is not true. While they are largely made with PLA (corn-based, renewable plastic), they also contain PBAT, a petroleum-based plastic, as a binder. This PBAT is critical. PLA is extremely slow to biodegrade outside of a tightly controlled environment, but PBAT biodegrades rapidly and allows the mailer to be home compostable. While most sellers of 100% compostable mailers are clear about what it is made of, it is common to find smaller sellers of the product that make misleading claims that the bags are made with 100% renewable content.

Why did you give corn a "Yellow" rating as source material for a poly mailer?  Corn is a terrible way to make plastic. Growing any crop, but especially GMO corn, for non-human consumption is a driver of so much environmental damage and many human rights issues worldwide.

• Genetically engineered corn (the kind used to make PLA) utilizes heavy doses of synthetic fertilizers, pesticides and herbicides to grow. These chemicals destroy soils, rivers and oceans. We believe soil health is one of the most important levers available in reversing climate change. We must not further destroy one of the planet's most incredible assets in our quest to solve another environmental challenge.
• It has been suggested that the use of "PLA for poly mailers makes up barely 0.05% of annual global corn crop" as a statement in defense of PLA as an eco-friendly resource. This way of thinking is immensely misleading. Compostable mailers' low impact today is driven by the fact that PLA/PBAT mailers are still such a tiny fraction of the global mailer supply. To be truly thoughtful about this question, we need to consider - what happens if PLA mailers becomes commonplace? It takes about 2.65 lbs of corn to make a pound of PLA (a broader range of 2.5-2.8 lbs corn to 1 lb plastic was shared via a phone call to Kansas State University Extension). If we converted all of our plastic to PLA, we would need to double the world's corn production - assuming 420 million tons of plastic are produced annually. Obviously that will not be our future, but this perspective helps highlight the fact that corn as plastic is a not a remotely viable long-term solution to our plastic problem.  
• Genetically engineered corn allows chemical companies such as ConAgra and Monsanto to further control our land, our public policy, our soil, and our agricultural economy.
• Only corn kernels are used to make PLA, the rest becomes agricultural waste, making it a pretty inefficient way to make plastic.

Why did you give 100% compostable poly mailers a "Yellow" rating for being compostable?   For two main reasons.

First, we believe compost should not be viewed as a way to "get rid of things" so that we can feel better about the waste we are generating. The primary goal of turning organic waste into compost should be creating an end product - humus - that can be laid on top of lands to create richer, healthier, more biodiverse soil. That means ideally, composters would accept largely food and yard waste. Unfortunately, as we push our municipalities to start accepting more and more for composting, we are generating a final compost product that we really wouldn't want to lay onto soils to enrich it. Compostable poly mailers are just the type of item we don't really want in our compost. They offer no value to the soil once biodegraded, and their inks and adhesives bring trace contamination (which, in high volumes, would add up). Some composters are starting to ban different types of bioplastic because they struggle to process it and the materials are degrading the value of their output (which they need to sell in order to keep their operation afloat). We think compostable packaging should be saved for packaging of food and yard waste. Ecommerce packaging should be designed for recyclability.

Second, the majority of Americans still do not have access to compost, so they end up landfilling their mailer instead. Which brings us to our next question.

Why do items that biodegrade in the landfill bad get a "Red" rating?   Landfills are designed to keep anything from biodegrading but inevitably, things do break down, emitting methane gas. While some landfills capture this gas, many do not, causing it to be emitted into the atmosphere. This is why we should avoid sending biodegradable items to the landfill.

Why did you give 100% recyclable poly mailers a "Yellow" rating for being recyclable?   For two reasons.

First, currently, most recycled plastic film is converted into composite lumber (like TREX), which is a great step but not the ideal end outcome for recycling. We reserve "green" ratings for material that are recycled back into itself, such as paper being recycled back into paper or plastic bottles that are recycled back into plastic bottles. Technically, bags can be converted back into plastic bags; however, the current cost of doing so makes this infeasible. We hope that over time bag-to-bag recycling becomes the norm.  

Second, is the fact that recycling poly mailers is not as easy as we want it to be. Plastic film is not accepted in most curbside recycling programs because the flexible material can get caught in the sorting equipment at materials recovery facilities. While most Americans can easily access thin film recycling at a local grocery store, this is an inconvenient step, leading to low recycling rates.  

Is plant-based / bioplastic / compostable plastic non-recyclable? Why can't I recycle it along with my other plastic film?

Because the chemical makeup of PLA/PBAT are so different from petroleum-based plastics (such as PET, LDPE, HDPE), this type of bio-film cannot be recycled in the same stream as traditional plastic film. Please do not recycle compostable poly mailers as they can be difficult for workers to separate out, and they go on to contaminate and degrade the quality of the final products being created with recycled plastic film. Managing this type of contamination can increase costs for reclaimers and remanufacturers and decrease their revenues, putting our ability to recycle these materials at risk.    

As of this writing, no attempts have been made to try to recycle PLA/PBAT compostable film. Pure PLA (such as an EcoProducts beverage cup) can technically be recycled, but no dedicated streams and services exist for this material in the US.

It is interesting to note that some bioplastics are in fact recyclable. Coke's "Plant Bottle" is partially made with bio-based PET (derived from sugarcane). This bio PET looks (structurally) just like regular PET, making the bottle recyclable with all other Coke bottles. The bottle is not compostable.

What is oxo-biodegradable and why is it so bad?  “Oxo-degradable” or “oxo-biodegradable” plastics contain additives that expedite the plastic’s ability to fragment into smaller pieces, meaning that these materials rapidly break down into microplastics - which are the most worrying component of plastic pollution. The Sustainable Packaging Coalition has this informative position piece with their view on oxo-biodegradable and other enzymatic plastic additives.

Tell me more about the carbon footprint impact of these different mailers?  First, it is important to remember that scientists currently consider lowering carbon emissions to be the world's number one environmental priority and our only hope in reversing climate change. This can lead to difficult decisions as companies struggle to balance sustainability priorities (such as going plastic-free versus lowering carbon footprint). Calculating an exact carbon footprint (the greenhouse gas emissions created by the production, transportation and disposal of an item) is an in-depth and highly specific process that requires the use of a Life Cycle Analysis tool like Compass and asks for detailed information on where an item is produced, how it is produced, where it is shipped, how it is disposed, etc. Additionally, different LCA's account slightly differently. Because of this, it is not feasible to make blanket numeric statements comparing two broad categories of products. However, countless Life Cycle Analysis tools have shown a few things:

• Many studies have been conducted demonstrating that when comparing two equivalent packages - the plastic package typically has a lower carbon footprint than the paper package. This is partly because plastic is generally cleaner to produce than paper, but also largely because you need a lot less plastic (by weight) to do the same function as paper. Here are a few articles to learn more: NPR Article,  Boustead Consulting & Associates (BCAL) Study, University of Oregon (interview with professor with extensive research into this topic), Franklin Associates Study (funded by Plastics Industry Group).
• To date, no detailed research as been conducted comparing the carbon emissions of 100% recycled plastic film with PLA/PBAT blend. However, the most heavily referenced study on this topic is titled, "Carbon Footprint of Packaging Films Made from LDPE, PLA, and PLA/PBAT Blends in South Korea" and takes quite a thorough look at this question, analyzing multiple scenarios. This study shows that virgin LDPE has a lower carbon impact than PLA/PBAT blends. These conclusions do not even consider the impact of 100% recycled plastic (which tends to lower carbon footprint of plastic by 30-70%) nor the other environmental harms of corn production.

We know the landscape of packaging and bioplastics is ever evolving! If you have ideas on new compostable plastic materials or new research that runs counter to what we share here, we'd love to hear from you! Contact us at saloni@ecoenclose.com anytime.