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  • Writer's pictureThe Pink Elephant Lady

LANDFILLED! Even When Clean and in Your Curbside Bin. Here's Why.

Berries, salad, cold takeout foods - look around the grocery store and you'll see that clamshell packaging is EVERYWHERE. But even if it has a recycling symbol on it, even if you clean it, dry it, and dutifully put it into your curbside bin, the overwhelming odds are it's getting landfilled. "But whyyyyyyy?" you ask. "I did everything right!"

What I just said might make some people involved in sustainability and recycling programs angry - they'll argue that because that container your organic berries came in has a #1 on it just like plastic water bottles, it's just as recyclable, and that I'm encouraging people to throw away valuable, recoverable materials. Unfortunately, they're misinformed.


A clamshell (pictured above) is a one-piece plastic container made of two halves joined by a hinge. Clamshells are a bit different than blister packs (pictured below), although the two terms are often used interchangeably.

Clamshells and blister packs are made of thermoformed plastic. Plastic water bottles, on the other hand, are blow molded plastic. And this distinction is what makes a water bottle highly recyclable and a clamshell garbage, even though they both have a #1 recycling symbol on them.

Note: Feel free to skip this paragraph if you're really not in the mood for a short less on plastics manufacturing! Blow molding, the way water bottles are made, is a manufacturing process for forming and joining together hollow plastic parts, like glass or plastic bottles (see the illustration below). A hot tube of plastic material, called a parison, is dropped from an extruder and captured in a water cooled mold. Once the molds are closed, air is injected through the top or the neck of the container. When the hot plastic material is blown up and touches the walls of the mold the material "freezes" and the container now maintains its rigid shape. Think of it as sort of like blowing up a balloon.

Thermoforming, on the other hand, consists of heating a plastic sheet to a pliable forming temperature. The sheet is then moved over or into a mold, and as it cools, it is trimmed to the proper size for the end product (see image below). This is the way clamshells are made. Think of it like wrapping a present or pouring jello into a jello mold.


Thermoforms and blow molded plastics don’t melt down at the same temperature. Clamshells would have to be recycled separately. The recycling number system has its limitations: crystalline C-PET (crystalizable PET - think opaque frozen diiner trays), amorphous APET (amorphous PET - think clear water bottles), and PETG (glycol modified PET - (think brittle clamshells) all have the same recycling symbol #1. Clamshells create significant contamination problems if they make it in with other plastics - this can ruin an entire batch of recyclable materials!

Unlike bottles, which are easy to identify in both manual and automatic sorting systems, thermoforms come in all shapes and sizes, which makes sorting them difficult - this drives up the cost of recycling them. Different MRFs have different sorting technologies. The high cost of automatic sorting technologies means these technologies are not available at most MRFs. If the investment has not been made in optical sorters or more sophisticated sorting technologies, the MRFs ability to sort thermoforms out may be time-intensive, resulting in higher costs. And if it costs more to recycle a material than what can be earned from selling that material to a manufacturer, that material will be landfilled.

At the end of the day, recycling is about economics, not 'saving the earth' - especially when virgin plastics are so cheap due to declining oil prices and there are no regulations requiring brands and manufacturers to use recycled materials.


Ideally, you'd be able to ask your municipality or hauler if it's okay to put clamshells in your curbside bin. However, you may not get an accurate answer. As you've read in this article, it's a bit more complicated than just looking for a recycling symbol on a bottle or container. There are multiple stakeholders in the recycling process, and they aren't all acting from the same set of assumptions.

Can you guess which state is investing in separately recycling thermoforms (clamshells)? Yep - California. California has estimated that around 250 million pounds of thermoforms are sent to disposal in the state annually. And now, a Mexican company that developed a system to process post-consumer PET thermoforms is opening a $7 million plant in the Los Angeles area.

I don't know that it's realistic to suggest avoiding clamshell packaging entirely since it's so ubiquitous not only in food packaging but in so many consumer products. I like Planted Detroit's salad packaging - it's made of 99% plant-based material and is certified compostable in an industrial composting facility. It's certainly the case that Michigan doesn't have much composting infrastructure in place yet, but you can bring your compostable foodware back to us. We are able to accept compostable containers, cups, and utensils. And you can also get the whole salad here, too!

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