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Human composting might be a viable funeral option while also being more environmentally friendly than other methods of postdeath care, according to a recent pilot study.

“Currently, in the U.S. there are two primary options for disposal or final resting of the human body, which are cremation and burial,” lead researcher Lynne Carpenter-Boggs said in a 16 February press conference at the annual meeting of the American Association for the Advancement of Science in Seattle, Wash.

“We are using fresh natural plant materials in addition to the human body and managing that through composting to produce high heat and rapid decomposition,” she said. The resulting material “is multidecadal carbon storage and improves soil health and plant growth.”

A Sustainable Alternative

In 2019, 93.8% of people who died in the United States were either buried or cremated, according to the National Funeral Directors Association. However, those two funeral methods each have a large environmental impact. Burial puts millions of liters of embalming fluid and thousands of cubic meters of wood into the ground. The carbon dioxide released into the atmosphere by cremation is equivalent to driving a car hundreds of kilometers.

More environmentally friendly funeral methods like alkaline hydrolysis and green burial are not widely available across the United States.

Composting deceased persons, or natural organic reduction, provides another sustainable alternative to cremation and burial. The concept got its start from the widespread practice of composting dead livestock.

“It’s actually a fairly common practice on livestock farms,” Carpenter-Boggs said. Carpenter-Boggs is a soil scientist at Washington State University in Pullman and a research adviser for the human composting company Recompose.

“Composting is an accepted practice and actually, in many areas, a promoted practice by departments of agriculture and departments of health for the disposal of livestock mortality.” She said the team first composted livestock materials and then fine-tuned the processes for human remains.

“It’s highly effective, but it’s taken some thought and some redesign to make this a process that would be allowable and acceptable for human use.”

“It’s highly effective, but it’s taken some thought and some redesign to make this a process that would be allowable and acceptable for human use,” she added.

In the pilot study, the researchers composted six donated research subjects using natural plant material as a starter. After 4–7 weeks, each body turned 2–3 cubic yards of starter into 1.5–2 cubic yards of compost and bones. Carpenter-Boggs said that as with cremation, a commercial composting facility would likely processes the material further to deal with the skeletal remains.

The composting process heated the decomposing material enough to sterilize it to Environmental Protection Agency accepted levels, killing off most common bacteria and pathogens, Carpenter-Boggs said. That would make the resulting compost safe to keep in an urn or incorporate into the ground.

“We achieved proof of concept, and by our last set of subjects I was very happy with the end material,” Carpenter-Boggs told Eos via email. “For commercial use, there will be further changes in the infrastructure and process.”

A Net Positive for the Environment

The total environmental impact of human composting can’t be fully assessed before it becomes a commercial process, Carpenter-Boggs said, but it would likely not be entirely carbon neutral. Composting facilities would still need to be built, heated, and powered. However, unlike cremation and burial, composting would provide a net positive impact on the environment and sustainability.

“There’s tremendous interest in the method by the public and by funeral homes.”

Composting “is a fabulous option,” Jennifer DeBruyn, a microbial ecologist at the University of Tennessee in Knoxville who was not involved with this work, told Science News. “The idea of applying it to humans, to me, as an ecologist and someone who has worked in composting, it just makes perfect sense, honestly.”

Human composting has a long way to go before it becomes commonplace. In May 2019, Washington became the first state to legalize the practice. Similar legislation is under consideration in California and Colorado.

“There’s tremendous interest in the method by the public and by funeral homes,” Carpenter-Boggs said. “It will take time to legalize the process in more states and to standardize the process for new facilities.”

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer


Cartier, K. M. S. (2020), Human composting is a greener way to go, Eos, 101, https://doi.org/10.1029/2020EO141218. Published on 06 March 2020.

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