The makers of a mycelium-based packing material want to make plastics obsolete. Photograph by Bartholomew Cooke

Gavin McIntyre, the co-inventor of a process that grows all-natural substitutes for plastic from the tissue of mushrooms, holds a pen or pencil in an unusual way. Gripping it between two fingers of his right hand, he moves his arm across the paper so that his wrist grazes the inscribed line; because of this, he uses pens with ink that doesn’t smear. When he draws an explanatory diagram of the chitin molecule—chitin is the principal component of mycelium, the white, rootlike vegetative structure of fungi—he bends over his work, then looks up earnestly to see if his hearer has understood. The gesture makes him appear younger than his age, which is twenty-eight. He wears glasses and has straight black hair, dark eyes, and several piercings, with studs in his lip and ears.

The other co-inventor, Eben Bayer, won’t be twenty-eight until June. Bayer is almost six-five, and often assumes the benign expression of a large and friendly older brother. His hair is brown, short, and spiky, his face is long, and his self-effacing manner hides the grand ambitions that people who come from small towns (Bayer grew up in South Royalton, in central Vermont) sometimes have. When he says, of the company that he and McIntyre founded, “We want to be the Dow or DuPont of this century,” he is serious. He is their company’s C.E.O., McIntyre its Chief Scientist. People with money and influence have bet that they will succeed.

Not long ago, McIntyre and Bayer and I sat and talked in the conference room of their thirty-two-thousand-square-foot factory, in Green Island, New York. They have been friends ever since they met in a design class at Rensselaer Polytechnic Institute, in nearby Troy, during the fall semester of their sophomore year, almost nine years ago. During our conversation, they leaned back and forth and sideways in the room’s flexible ergonomic chairs, meanwhile tapping their iPhones to send and receive texts and e-mails to and from many people, perhaps including each other. McIntyre was wearing running shoes, jeans, a plaid shirt, and a forest-green pullover, and Bayer approximately the same. As they talked about their invention, they mentioned Burt Swersey, the teacher at R.P.I. who became their mentor and adviser.

I said that when I had talked to Swersey a few days before, I had told him of an invention of my own—a device to remove plastic bags from trees, which my friend Tim McClelland and I patented in 1996. Swersey had reacted to my small boast with scorn, saying, in so many words, that it was ridiculous to focus on annoyances like plastic bags in trees when humanity had far worse problems. McIntyre and Bayer both laughed. “Burt was always telling me my inventions sucked!” Bayer said. “And when I came up with an invention he liked he would only ask how I was going to make it better. If I came in with a cure for cancer, Burt would’ve said, ‘O.K., but what about H.I.V.?’ ”

A real, serious problem that humanity has right now is Styrofoam. If the name is used accurately, it applies only to the foamed, extruded polystyrene product patented by Dow Chemical in 1944. Dow’s Styrofoam is blue and serves mainly as a building insulation. More commonly, however, Styrofoam is the name people give to the white foamed polystyrene from which packing peanuts and coffee cups and fast-food clamshells are made. In widespread commercial use since the nineteen-fifties, Styrofoam is now everywhere. After Hurricane Sandy, its clumps and crumbs covered beaches along the Atlantic Coast like drifts of dirty snow.

Pieces of Styrofoam swirl in the trash gyre in the Pacific Ocean and litter the world’s highways and accumulate in the digestive systems of animals and take up space in waste dumps; to reduce New York City’s landfills, Mayor Bloomberg recently proposed a ban on the commercial use of Styrofoam containers. Foamed polystyrene breaks down extremely slowly, in timespans no one is sure of, and a major chemical it breaks down to is styrene, listed as a carcinogen in the 2011 toxicology report issued by the National Institutes of Health.

The Dow chemist who invented Styrofoam, O. Ray McIntire, made it by accident while looking for a substitute for rubber insulation. Many plastics were invented to imitate natural substances, like rubber, wood, bone, silk, hemp, or ivory.

Bayer and McIntyre’s invention, in postmodern fashion, creates natural substances that imitate plastics. The packing material made by their factory takes a substrate of agricultural waste, like chopped-up cornstalks and husks; steam-pasteurizes it; adds trace nutrients and a small amount of water; injects the mixture with pellets of mycelium; puts it in a mold shaped like a piece of packing that protects a product during shipping; and sets the mold on a rack in the dark. Four days later, the mycelium has grown throughout the substrate into the shape of the mold, producing a material almost indistinguishable from Styrofoam in form, function, and cost. An application of heat kills the mycelium and stops the growth. When broken up and thrown into a compost pile, the packing material biodegrades in about a month.

The name of the company is Ecovative Design, L.L.C. “Ecovative” is pronounced with the accent on the first syllable, like “innovative,” and the first “e” is long. I found it hard to get the hang of pronouncing the name, and for a while I thought that Bayer and McIntyre should look for a simpler one. But after talking a lot about the company with its principals and employees, almost all of whom are under thirty, I got to like “Ecovative” because of the way they said it. The people who work for the company are devotees of it, and of larger causes. Some employees took vacation days to participate in Occupy Wall Street; two of them were arrested there.

Referring to their product, the Ecovative people sometimes use the phrase “disruptive technology.” Founded six years ago, the company has doubled in size every year, and now employs about sixty people at the Green Island factory. Last June, Ecovative licensed its process for making mycelium-based packing material to Sealed Air, a $7.6-billion international packaging company best known for Bubble Wrap. Sealed Air is building a factory to manufacture Ecovative packaging products in the Midwest. The products can be made almost anywhere, with local agricultural wastes and minimal use of energy. Ecovative’s eventual goal is to displace plastics all over the world.

Kathleen and Gary (Mac) McIntyre, Gavin’s parents, have spent most of their careers working for Brookhaven National Laboratory, on Long Island. Mac is a mechanical engineer who designs and sometimes also makes parts for Brookhaven’s heavy-ion collider and other experimental apparatus. Kathleen, whose degrees are in radiation science and biology, has held a variety of jobs at the laboratory. She is now the operations manager for its Radiological Assistance Program. Gavin was a good student and an Eagle Scout, and he picked up a wide knowledge of science and engineering from his parents. Starting in high school, he did intern jobs at Brookhaven. By the time he was twenty, he was working on accelerator optics, helping to design programs for the focussing and steering of particle beams.