The Science Of Composting Human Remains : Short Wave There aren't that many options for putting your loved ones to rest. There's burial. There's cremation. Now, later this year in Washington state, it'll be legal to compost a human body. Soil scientist Lynne Carpenter-Boggs tells us how the process works and why she describes it as "beautiful." Carpenter-Boggs is also a research advisor at Recompose, a human composting company in Washington. Follow host Maddie Sofia on Twitter @maddie_sofia. Email the show at

Compost Your Loved Ones

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You're listening to SHORT WAVE from NPR. Today, a cheery topic, death - well, more specifically, what to do with human bodies after death. It's not something lots of people like to talk about, even Lynne Carpenter-Boggs, a soil scientist at Washington State University.

What is your feedback you've been given when you, like, talk about this at parties?

LYNNE CARPENTER-BOGGS: (Laughter) I don't often talk about this at parties. My husband seems to like to just throw it out there in random (laughter) audiences.

SOFIA: Husbands.


SOFIA: But it is a new way that people in Washington state can dispose of their bodies after they're dead - compost it. Yeah, it's not just for food scraps and leaves. Composting human remains will be legal in Washington state this year starting in May. Lynne actually studied how to do this for a company planning to offer the service.

CARPENTER-BOGGS: Even when there's a little bit of negative or just unfamiliarity with the idea, once you start talking about how beautiful that this can be, we see that there's a lot of people who are really interested in it.


SOFIA: So how do you do it? Well, today on the show, Lynne Carpenter-Boggs tells us about her pilot study that took six donated human bodies and turned them into compost.


SOFIA: OK, so I get it. Some of you are probably like, why would somebody be into composting human remains? Well, typical ways of dealing with our bodies in the states have their downsides. There's the carbon footprint of cremation, the hundreds of thousands of tons of wood and concrete that we put in the ground with caskets and just the sheer amount of space graveyards take up.

CARPENTER-BOGGS: There are increasing numbers of cities where they're no longer allowing extension of cemetery grounds.

SOFIA: So before she got into human composting, Lynne Carpenter-Boggs had a long career helping farms compost dead livestock. That work caught the attention of Katrina Spade, the founder of the company Recompose and one of the people behind the whole effort to legalize human composting in the state. She recruited Lynne to prove that you can safely compost a human body. But, for sure, composting humans feels way different than composting livestock.

CARPENTER-BOGGS: Oh, definitely. Yeah, it just doesn't feel right. It feels like a sort of a too - little-too-natural (laughter) method. You know, it feels very agricultural. And most people are just not familiar with how composting works. And, you know, it didn't seem like anybody would ever really accept it as a method. So to take the concept and the basic principles that we know work really well and put it into a really different context where it becomes not only acceptable but a really beautiful process, that has been the goal.


SOFIA: The first thing that happens is that the body is placed in this long barrel-like container.

CARPENTER-BOGGS: So what it looks like is that the body is laid onto a bed of plant materials. And then more plant materials are laid on top of the body, and the door is closed.

SOFIA: One of the important parts of this equation is all that plant material. It has to contain a special ratio of carbon to nitrogen to give the microbes some of the energy they need to be super active.

CARPENTER-BOGGS: And that also creates high temperature.

SOFIA: From there, they tweak the airflow, even rotate the container, all to keep those little bacteria feasting - you know, breaking everything down.

CARPENTER-BOGGS: Well, you know, I don't want to get too gross.


SOFIA: Well, get a little gross for me, Lynne.


SOFIA: Or as gross as you're comfortable with.

CARPENTER-BOGGS: Most of the activity is by bacteria, and they don't have mouths like (laughter) the larger organisms we think about. They release enzymes outside of their bodies, so essentially, you have trillions of little enzyme- and acid-making machines that are leaking out these enzymes and acids. And it's that chemical mix that primarily makes things decompose.


CARPENTER-BOGGS: So the cells come apart, molecules come apart, and then those same bacteria are then able to feed on the very tiny molecules that have been released from that chemical process.


SOFIA: In Lynne's pilot study, trying out that process took about four to seven weeks. The company Recompose hopes to standardize this process so it only takes 30 days.

What does the material look like? Like, I am having a hard time visualizing it.

CARPENTER-BOGGS: Oh, you have material that is fairly fine. It looks something like a little bit larger diameter potting soil, so it looks like compost.

SOFIA: So funerals are extremely expensive in general, and in 2020, people will be able to do this in Washington state. Do you think people will do it because it's cheaper? Do we know yet?

CARPENTER-BOGGS: The goal price, I believe, will likely be somewhere between cremation and typical burial, so it's likely that cremation would still be a cheaper option. So while part of the attraction for people will be price, I think that it will be noneconomic attractions that will bring more people to it.

SOFIA: Sure. No, that makes sense to me. You've used the word beautiful to describe this process. What about it do you find beautiful?

CARPENTER-BOGGS: Yeah, that's probably with my not-so-scientist hat on.

SOFIA: I like that hat.


SOFIA: I like that hat.

CARPENTER-BOGGS: Yeah. So, to me, even going through the unique situation of having donors who I didn't personally know - but to lay them on fresh plant materials, which smell lovely, and to cover them up with more fresh plant materials, and to know that it is trillions of microorganisms having a great time (laughter) that then convert that material into something that, you know, was completely different-looking than when we closed it up a month ago and that, again, was a pleasant material to smell and to touch but very different than what we started with - so it's both that this transformation is happening and also that you then have something that is going to further improve the land. To me, those are all beautiful.


SOFIA: Lynne Carpenter-Boggs is a professor of sustainable and organic agriculture at Washington State University and research adviser with Recompose.


SOFIA: Today's episode was produced by Rebecca Ramirez and edited by Viet Le. The facts were checked by Berly McCoy, and Ted Mebane helped with engineering. I'm Maddie Sofia. This is NPR's SHORT WAVE. We'll see you tomorrow.


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