Turning human bodies into compost works, a small trial suggests

SEATTLE — Human bodies make great worm food. That’s the
conclusion of pilot experiments with six dead bodies that were allowed to
decompose among wood chips and other organic material.

The results, presented
February 16 at the annual meeting of the American Association for the
Advancement of Science, suggest that composting, also called natural organic
reduction, is a way to handle dead bodies that’s easy on the Earth.

Disposing of dead human bodies can be
a real environmental problem. Embalming relies on large quantities of toxic
fluid, and cremation throws off lots of carbon dioxide. But composting, in
which microbes break down the bodies into soil, “is a fabulous option,” says Jennifer
DeBruyn, an environmental microbiologist at the University of Tennessee in Knoxville
who wasn’t involved in the study.

In 2019, Washington became
the first state to legalize natural organic reduction as a post-life option. A Seattle-based
company called Recompose expects to start accepting bodies for composting soon.

In a news briefing, soil
scientist Lynne Carpenter-Boggs of Washington State University in Pullman
described a pilot experiment in which six bodies were put into vessels that
contained plant material and routinely rotated to provide optimal conditions
for decomposition. About four to seven weeks later, microbes in the material
reduced the bodies to skeletons.

Each body resulted 1.5 to 2
cubic yards of soil-like material containing bones. Commercial processes would
likely use more thorough methods to process the bones, said Carpenter-Boggs,
who is a research adviser to Recompose. Her analyses also have shown that the
resulting soil meets safety standards set by the U.S. Environmental Protection
Agency for such contaminants as heavy metals.

Animal carcasses have long been turned into rich soil in
similar ways, DeBruyn says. “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.” The heat produced by busy
microbes has the added benefit of killing off dangerous pathogens. “Automatic sterilization,”
DeBruyn calls it. Once when composting cattle, “the pile got so hot that our
temperature probes were reading off the charts, and the wood chips were
actually scorched,” DeBruyn says. 

One thing not killed by high
heat is prions, extremely durable misfolded proteins that can cause disease (SN: 9/9/15). That means that composting “wouldn’t be allowed for
people who have diagnosed Creutzfeldt-Jakob disease,” Carpenter-Boggs said.

It remains to be seen how
widely adopted the process of composting human bodies becomes. Lawmakers in
other states are considering the method, Carpenter-Boggs said.