"It's a good thing that they are buying compostable product, as long as people put it in the right containers," said Brian Rosa with the State Division of Pollution Prevention.
The cafeteria sells about 1500 corn cups a week. Roughly half stay in the restaurant and are properly tossed out with compostable food waste, but the other half are taken to go and end up where no one expects.
The plastic cups with the green stripes don't fit into the plastic recycle bins at the General Assembly because the cups are not supposed to be recycled. People often throw them in the bins anyway. That means they end up in a dump.
"If they take it out for take-outs, chances are it's going to the landfill and it's not going to do any good," Rosa said.
What's the difference between a landfill and a compost pile? The cups need water to break down into biodegradable material and landfills are kept dry to prevent chemicals from leaching out into groundwater.
"Landfills are designed for things not to degrade. They squeeze out the air, moisture and sunlight, all necessary for biodegration to happen," Rosa explained. "Those things will be entombed in these things for many, many years."
Senator Ellie Kinnaird of Carborro says she recycles and composts at home and even she was surprised a cup wrapped in green cannot be recycled.
"It says recyclable. I guess I would just put it in the trash thinking it would just decompose," she offered.
The general assembly spends about a thousand dollars a month on corn-cups - about $18,000 so far. They're twice as expensive as paper cups.
Senator Kinnaird says lawmakers will improve.
"We really need to get better information. Our heart's in the right place. We tried to do the right thing. And we'll do better," she said.