RALEIGH, N.C. — Millions of families use baby diapers that end up in landfills.

In fact, more than 1,800 tons are used daily in the U.S., and about 20% of total waste in landfills is discarded diapers.

Because diaper materials aren’t biodegradable — with plastic in the lining and a filling made with petrochemical-based polymer (sodium polyacrylate) — throwaway diapers are toxic to the environment if left untreated.

To cut down on environmental waste, Scott Bolin — co-founder of Raleigh, N.C.-based startup Tethis — has developed a green alternative: a biodegradable material made from corn starch, rather than petrochemical polymer.

Corn starch may sound like an unusual ingredient to include in a diaper, but it’s safe to use, available in large quantities and cheap to buy.

“The diaper industry has struggled to move to greener products,” Bolin said. “Right now, most diapers in the world use a petrochemical that comes out of an oil refinery. But what consumers want is a renewable diaper.”

The process, which Tethis has been working on since 2012, includes a few steps. A corn starch-based mixture is put through an extruder, a machine that changes material as it’s compressed.

A noodle-like material comes out the other end and is eventually turned into a powder. It’s then mixed with other substances to enhance its absorbency.

Following a round of successful customer trials, Bolin said diaper manufacturers have already taken note of the innovation both in the U.S. and Europe.

He declined to name the companies that have already reached out to him but said the interest is serious enough for Tethis to move ahead with production off the biopolymer.

To meet potential demand, the company is opening a production plant in Zebulon, N.C. this summer. The new 15,000-square-foot facility will employ between 15 to 20 people and produce about 700 tons of the biorenewable polymer each year. The goal is to ramp up production to 10,000 tons by mid 2018.

In the meantime, Bolin aims to form partnerships with some of the diaper manufacturers that make up a $40 billion global market.

Although brands such as The Honest Company, cofounded by actress Jessica Alba, tout eco-friendly disposable diapers, they include a bio-based absorbent core. This means they are made of a wheat and corn blend that still features sodium polyacrylate. Tethis’ material would eliminate the chemical polymer from those diapers as well, said Bolin.

However, companies would still have to figure out ways to eliminate the plastic in a diaper’s lining.

“If we can even make today’s diapers 10% better for the environment, this incremental change can have an immense impact,” said Bolin.