Corn plastic is becoming more common in New Hampshire. Used as food packaging, it shows up in grocery stores, take out containers, and even in water bottles.

Manufacturers tout say because it’s made from corn, these items can be composted. But New Hampshire Public Radio’s Environment reporter Amy Quinton has found, the story is a lot more complicated.

Manufacturers call corn-based cups "100% compostable," but the story is usually more complicated. (Courtesy sdbrown)

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It’s the lunch hour inside the Boloco restaurant in Concord.
The burrito take-out chain is a certified green restaurant- so customers won’t find Styrofoam cups and containers.
Boloco uses a product called Greenware, which is a plastic made from corn, not oil.
380 1:17 “Basically you pick it up, you wouldn’t know the difference that it’s not plastic, but it’s something that’s much better for the environment”
That’s Brian Wilpert, General Manager of Boloco in Concord.
Their Greenware cups –like other corn plastics - are 100-percent compostable.
Customer Scott Hayden says he likes the idea.
“383 :15 I think it’s pretty neat, its compostable, this will disappear, it will naturally degrade over time, that’s pretty cool.”
Nebraska-based NatureWorks is the largest manufacturer of corn plastic.
Spokeswoman Mary Rosenthal says the compostable plastic can be made from many plants, including cane sugar, cassava, and tapioca.
But since NatureWorks, which is owned by Cargill, is located in corn country, corn is the cheapest source for the plastic.
And Rosenthal says using the renewable resource is much better than making plastic from petroleum.
Mary1 “the other key advantage is the significantly reduced carbon footprint, this material not only emits less greenhouse gases, up to 50-percent less greenhouse gases, it also uses 80 to 90 percent less fossil fuel in order to produce”
Corn plastic also produces fewer toxic substances when burned.
But some of the environmental benefits are misleading, especially when it comes to disposing of the product.
Since it’s made from organic material, it’s technically compostable.
And it will degrade in commercial compost facilities.
But it’s not likely to disappear in your backyard bin.
Don Maurer, with New Hampshire’s Department of Environmental Services Solid Waste Division, says that’s a problem.
389 Maurer “1:01 there’s only one real large one in the state and that’s EarthTenders in the Farmington area, New Hampshire does not have a lot of compost facilities.”
Eva Christensen is the owner of EarthTenders.
She says composting sites like hers operate differently than backyard bins.
Eva1a “the biggest difference probably is exposure and the temperatures they generate. In a backyard pile, you don’t build up as much mass so you wouldn’t expect as high a temperature”
And temperature here is crucial.
Manufacturers say the compost piles need to reach well over 140 degrees, with 80-percent humidity, for at least 10 consecutive days.
Then, it will take less than 90 days for corn plastic to disappear.
It’s a pretty specific requirement.
But Natureworks spokeswoman Mary Rosenthal says the plant-based products can be recycled.
However, there’s another caveat.
Mary2 “theoretically you can take the material and either chemically or mechanically recycle it, but the current collection systems today don’t typically recycle things like Greenware or plastic clamshells or things of that sort.”
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A huge machine called a baler is sorting materials at the Waste Management recycling center in Rochester.
Here – and in similar facilities across the country – they recycle only those plastics with a one or two on the bottom.
That’s typically items like soda bottles, milk jugs, and laundry detergent containers.
Senior District Manager Alan Davis says there’s not enough of a market for anything else –including corn plastic.
37 3:48 if the corn plastic gets thrown into people’s recycling bins with their other plastics and aluminum and co-mingled, it’s going to end up in our landfill 3:55
And manufacturers of this green alternative admit that for now, most of their corn plastic will likely end up in landfills.
There it’s not likely to degrade any faster than conventional plastic.
For NHPR news, I’m Amy Quinton.