In the spring of 2018, Katrina Spade took a short plane ride from Seattle, Washington, across the state to a town called Pullman. She met with Washington State University researchers with whom she had been working to create a unique soil. She scooped up a small mound of the soil and held it in her hand. It was the first proof that a human body could be safely turned into earth, like food scraps in a compost bin.

Spade first considered composting human bodies while studying architecture as a graduate student at the University of Massachusetts Amherst in 2011. She had been learning about the environmental toll of human death.

Each year in the United States, just over half of the nearly 3 million deceased are rapidly disintegrated into ash through cremation, each releasing about 100 kilograms of CO₂. About 43 percent of American deaths result in embalming and burial. The bodies are injected with a solution made up mostly of formaldehyde, a carcinogen, in what adds up to about 800,000 gallons of the solution per year. Then they are placed into thick caskets of wood, copper, bronze, steel, and/or concrete—all intended to slow their disintegration underground. The burials take up a lot of land, usually consisting of pristine lawns that require polluting fertilizers and hefty water use to maintain. Urban planning experts worry there’s not enough land available to support the upcoming burials of an aging baby-boomer population.

Around the time Spade learned about the environmental impact of death care, she also learned that farmers sometimes compost their livestock. She began designing a system to compost human bodies—“recomposition”—which eventually became her
thesis project.

After graduating, she received grant money to continue pursuing the idea. A team of forensic anthropologists at West Carolina University had carried out a successful bare-bones proof-of-concept study using a body and a mix of wood chips on a forest floor. She founded her company, Recompose, and partnered with soil scientists at Washington State University on a study to compost corpses inside a vessel. The study successfully turned six donor bodies into soil. Right now, she’s recruiting investors to fund the world’s first recomposition center, in downtown Seattle.

To compost anything, you need four basic ingredients: carbon, nitrogen, oxygen, and moisture. To compost a corpse, Spade’s design puts all components inside a hexagonal vessel. A mix of wood chips, straw, and alfalfa blankets the vessel floor. The body is laid upon the bed, and more mixture is layered on top. Vents provide ample oxygen.

The oxygen, carbon, and nitrogen attract and feed an abundant community of microbes. As the microbes eat away at the pile, their movement emits heat—as much as 120 to 150 degrees Fahrenheit. This is the perfect environment for a thermophile, or a type of microbe suited to heat. Thermophiles continue to break down the body; after about a month, the process can convert a body into one cubic yard of soil.

The process generates considerable atmospheric savings. Researchers from two universities in the Netherlands recently calculated that each person who opts to be composted rather than cremated will spare the environment more than 84 kilograms of climate change–causing CO₂.

Though composting has been shown to work, it remains a possibility not yet available to the public. Whether it can scale to meet the demands of a growing, and inevitably dying, population remains to be seen.

Yet, there’s precedent for a cultural shift toward environmentally friendly funerals. Though cremation is popular today, in 1990 it was the preference of only 15 percent of US citizens. According to a survey by the advocacy group Green Burial Council, many people began choosing cremation over burial because they considered it a greener option, since it uses less land. Natural burial has also risen in popularity in the past two decades, with a growing number of registered natural burial sites in the US, the UK, and Canada. Spade and her colleagues at Recompose have heard from people around the world who are interested in leasing out their technology, she says. She and her coworkers are speaking to funeral homes in Brazil and the Netherlands and have heard from interested individuals in Australia and Europe.

The process is estimated to cost a consumer around $5,500. That buys friends and family time with the composting vessels, the actual transformation of human to soil, the body’s transportation, and a death certificate. Compare that to the median cost of a funeral with a conventional burial, around $7,360, or a funeral with cremation, around $6,260.

Consumer choice is only one piece of the puzzle—recomposition isn’t yet legal anywhere. In other states and in countries around the world, the funeral industry has proven stubbornly resistant to innovation. The most recent example of this resistance has played out through efforts to legalize alkaline hydrolysis, another green alternative which cremates bodies using a mostly-water solution instead of heat. It’s currently legal in 16 US states but has faced contentious legal battles and religious criticisms in some states. New Hampshire legalized the technology for two years, then repealed it in 2009. During hearings on a 2015 bill to legalize the technology in Indiana, Representative Dick Hamm made an impassioned speech comparing it to letting bodies “run down the drain.” Hamm owns two casket companies. Recomposition could run into similar problems in states resistant to change.

But in Washington, where the funeral industry has relatively few barriers to entry, the state legislature passed a bill in April that would legalize both recomposition (which they’re calling natural organic reduction) and alkaline hydrolysis. “It’s a way for death care to be part of the climate drawdown puzzle,” Spade says, “and we’re excited to be part of that.”

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Jennifer Monnier is a freelance science journalist in Seattle, Washington. She writes about energy, agriculture, environmental research, and how people are adapting to climate change. Her work has appeared in Crosscut, Spectrum News, and other publications.