One in three Americans owns a home brewing machine that uses the single serve pod-like K-cup or a similar brand. Keurig Green Mountain made $4.7 billion in revenue last year, much of that coming from the sale of the pods of coffee that can only be used once. John Sylvan, the inventor of the iconic K-cups, contributes to neither of these statistics as he does not own a Keurig machine or use the K-cups. “I don’t have one. They’re kind of expensive to use,” he admits frankly, “plus it’s not like drip coffee is tough to make.”

Sylvan sold his share of the company in 1997 for $50,000, but that is not why he regrets his invention of the brewing system that has fundamentally changed the way many Americans experience coffee.  As with plenty of environmental activists, he’s concerned with the plastic pods ending up in landfills. With enough K-Cups sold in 2014 to encircle the globe at least 10.5 times, Sylvan “feels bad sometimes” that he ever invented the cups.

The K-cups re manufactured using #7 plastic. Plastic materials are classified using a resin identification code that allows the objects made using the plastics able to be easily sorted and subsequently recycled. Numbers 1 through 6 are defined by their plastic type, but number 7 plastic is defined as “other”. Comprised of a multilayer combination of plastics, this material is not traditionally recycled. The #7 plastic K-cups are also not biodegradable.

“No matter what they say about recycling, those things will never be recyclable,” said Sylvan. “The plastic is a specialized plastic made of four different layers.”

Keurig Green Mountain’s sustainability report indicates that it’s working to make the single-use containers fully recyclable by 2020, but Sylvan argues this is not possible with the way the pods are designed.

“I gotta be honest with you,” Monique Oxender says, “we’re not happy with where we are either. We have to get a solution, and we have to get it in place quickly.” Oxender is Keurig Green Mountain’s Chief Sustainability Officer. She was onboarded in 2012 to assist in damage control after the #KillTheKCup exploded on the internet, complete with a video.