This week, Washington Governor Jay Inslee signed a bill to allow the composting of human remains within the state. It is the only state in the US—and possibly the only government in the world—to explicitly allow "natural organic reduction" of human remains.

The bill also legalizes alkaline hydrolysis, a base chemical process that also uses heat, pressure, and water to liquify remains. Bone is not liquified in the process, so it can be crushed and given to loved ones. Alkaline hydrolysis is legal in 19 other states, according to the New York Times.

The new law, which will take effect in May 2020, is a boon for Recompose, an organization that wants to offer composting as an alternative to green burials and cremation. Traditional burials usually require embalming chemicals and caskets that will remain in the ground for centuries if not millennia. Green burials, which forgo elaborate caskets and embalming chemicals, still require some amount of land, which can be expensive, especially in urban areas. Cremation, on the other hand, requires a significant amount of energy (mostly from fossil fuels) to complete, releasing greenhouse gases in the process.

Recompose, on the other hand, hopes to serve people who want a less environmentally-taxing final rest. Composting deceased livestock is already practiced by some farmers, and Washington State University conducted a trial run of the process on human remains, using six bodies that had been donated for research purposes. The process took about four weeks to complete, and it created roughly one cubic yard of soil per person.

Recompose says that its reduction process for human remains will occur inside "reusable, hexagonal recomposition vessels."

"When the process has finished, families will be able to take home some of the soil created, while gardens on-site will remind us that all of life is interconnected," the organization says.

Bones and teeth are reduced in the process as well, as the environment within the hexagonal pods is controlled to support microbes and bacteria that easily break down tougher human matter. Much like with a backyard composting rig, the pods get mixed periodically to make sure the decomposition is even. Metal fillings, pacemakers, and artificial body parts are removed and recycled if possible.

Katrina Spade, the founder of Recompose, told the Times that the process will cost about $5,000—more than a traditional cremation, but less than a traditional burial. "The material we give back to families is much like the topsoil you'd buy at your local nursery," Recompose says on its website.

Although composting itself is not emissions-free, Recompose says it has conducted a Life Cycle Assessment to compare conventional burial, cremation, natural burial, and recomposition. "In our preliminary findings, recomposition performed the best out of all four options in the majority of categories," the organization's website claims. Although there are few public studies on animal or human remains to confirm Recompose's result, more general studies comparing composting to incineration of agricultural waste seem to support it.