What is Liquid Cremation and Why Isn't it Legal?

By Sarah Zhang on at

Excuse the bluntness, but once we shuffle off this mortal coil, our bodies are nothing but bags of live bacteria and dead cells. We can attempt to slow our decay (embalming), or we can preempt it with a destructive blaze (cremation). We can also dissolve our bodies with lye, using an increasingly popular procedure called alkaline hydrolysis.

Or least some of us can. Alkaline hydrolysis—also known as liquid cremation or water cremation or bio-cremation—is currently only legal in one Canadian province and 8 US states. Despite being one of the cheapest and most environmentally-friendly forms of dealing with a cadaver, it is not an option for most of us.

Why? Death customs are fraught, and (legal) change can be excruciatingly slow. Plus, there’s a lot of misunderstanding of how alkaline hydrolysis works. It does not mean liquefying grandma and pouring her down the drain.

How does alkaline hydrolysis work, exactly?

Like ordinary cremation, all that remains after alkaline hydrolysis are remnants of bone, which are ground up into ashes we place into urns. How it gets there, though, is very different.

One way to think about it is that alkaline hydrolysis rapidly speeds up the ordinary decay process using heat, pressure, and an alkaline substance such as potassium hydroxide or sodium hydroxide. The body is put inside a steel vessel with 302 litres or so of water that is heated up to 149 degrees C—killing any microbes and even destroying prions responsible for the human version of mad cow disease. After an hour or two, most of the body dissolved into liquid. The remaining bone is ground up into ash.

Short of letting a body decay naturally, alkaline hydrolysis is the greenest option out there. While it uses a lot of water, it creates just a quarter of the carbon emissions from cremation and uses just 1/8 of the energy. And let’s not even get started on all the toxic chemicals in embalming. So it’s a simple process that’s very clean, and leaves you with basically the same “cremains” that you get with traditional cremation.

The death tech trend that’s coming next

“I think there’s a lot people who just don’t understand the process,” says Terry Regnier, Director of Anatomical Services at Mayo Clinic, which successfully got Minnesota to become the first state to legalise the process in 2003. The clinic now uses the process on all bodies donated for research and teaching. The process is currently legal in Colorado, Florida, Illinois, Kansas, Maine, Maryland, Minnesota, Oregon, and Saskatchewan.

A few years ago, when Edwards Funeral Service in Ohio bought an alkaline hydrolysis machine, they were ordered to stop amidst some controversy. Catholic clergy, for instance, said it wasn’t “showing respect for that body.” It certainly doesn’t help that the process was first developed to dispose of dead animals.

Here in the UK the controversy isn't as common as it is in the States, but the process still hasn't been legalised. Ironic, considering a number of commercial units being installed in the US have been developed by a Glasgow-based company

“The biggest misunderstanding is that they think the whole body goes down the drain,” Regnier says. Even with that misunderstanding out of the way, though, it’s easy to see why people might be squeamish about being “poured down the pipe.” But that might just show our ignorance about how dead bodies are usually treated. Blood and body liquids are poured down the drain when coroners do embalming — and burned particles pouring out through the smokestacks in cremation.

Alkaline hydrolysis could certainly use an image makeover, and it’s really just a matter of choosing the right words. “Burning grandma in fire seems to be violent,” Phil Olson, a philosopher of science, told the Atlantic. “In contrast, green cremation is ‘putting grandma in a warm bath.’”

Regnier says that interest is growing, and he’s given hundreds of tours of Mayo’s facility. And in their donor program, no families out of hundreds have refused alkaline hydrolysis for their dearly departed loved ones. Granted, people who donate their bodies to science are probably not the most squeamish about what ultimately happens either. “I’d have no hesitations for having it done for myself or another family member,” Regnier says.

With air pollution, lack of space, and carbon emissions making traditional burial methods even more problematic, alkaline hydrolysis is poised to become the method of choice. Of course, that requires the traditions around death to shift as well — and for people to let go of a certain squeamishness. But we’re a culture that thinks wiring shut the jaws of corpses and stuffing them full of cotton is okay, so that’s not an impossible shift.

Top image: Resomation Ltd