These items don’t always compost. “Not all ‘certified’ compostable items will actually compost (break down) as fully or quickly as we need them to. This is because certification standards test compostability based on laboratory conditions,” not always in  “real world” environments. Thus, bits of plastics remain in the compost—something people do not want.

Contamination happens. People don’t always sort “compostable” plastics from non-compostable plastics—yes, it’s tough to tell the difference. But the composters say that these materials must be removed, “either at the start (when we receive them) or at the end (as pieces of garbage are mixed in with finished compost),” which increases the composters’ operating costs and degrades their product.

They hurt resale quality. “We don’t want to produce finished compost that is contaminated with fragments of packaging and serviceware, and our consumers won’t purchase contaminated material,” the composters explained. “Contamination lowers the value of our product, making it difficult and sometimes impossible to sell.”

We can’t sell to organic farmers. “Farmers often use compost in the production of certified organic foods,” said the composters. “National standards prohibit the use of many different packaging materials when making compost used to grow crops certified as USDA Organic.”

They may threaten human and environmental health. Chemicals in paper packaging, such as perfluorinated alkyl substances (PFAS) to provide water and grease resistance “can transfer from compost to ground and surface waters, can be taken up by plants from compost and may have negative health impacts,” noted the message. (Here I would like to add that this is perhaps one of the best cases for using plastics for take-out food containers rather than the less eco-friendly paper.) PFAS is being phased out by some makers of paper containers, but it has not been regulated out of existence.

It increases our costs and makes our job harder. “Some of us have accepted compostable packaging in the past and found that loads of compostable packaging require us to change our processes, adding water, using more energy and spending additional resources to produce finished compost,” said the composters. “Some types of compostable packaging mostly degrade into carbon dioxide and water and leave behind little of value for all of the extra effort required.”

Just because something is compostable doesn’t mean it’s better for the environment. “Oregon DEQ has found that compostable serviceware often has a larger (life-time) environmental footprint than non-compostable items. For example, compostable materials may require more fossil energy use, release more greenhouse gases or result in more ecological toxins than their non-compostable counterparts, mostly due to how they’re made,” explained the composters in the message. “The research confirms what scientists already know: What materials are made of, and how they’re made, may be more significant than whether they’re composted vs. landfilled. ‘Composting’ and ‘compostable’ are not the same idea. Composting is a beneficial treatment option for organic wastes, but ‘compostable’ is not a guarantee of low impact.” (I would advise that the next time you are at a large conference or function where you are served appetizers on paper cocktail plates and given “compostable sporks” with which to eat, explain to the servers—or, better yet, the food manager—that these items are really not compostable and they would be doing more for the environment to use “recyclable” plastic plates and serviceware.)

In some cases, the benefits of recycling surpass those of composting. The composters suggest that there are some cases where if an item, like paper bags, can be either recycled or composted, the better option just might be recycling, which “can provide greater overall environmental benefits than composting does.”

Good intentions aren’t being realized. “Compostable items often cost more, sometimes up to five times as much as non-compostable alternatives. That’s a lot of money spent on products that might not actually help the environment—money that could be spent in more productive and beneficial ways.”