LAFAYETTE, Colorado — In a suburban Denver warehouse tucked between an auto repair shop and a computer recycling business, Seth Viddal is dealing with life and death.

He and one of his employees have built a “vessel” they hope will usher in a more environmentally friendly era of mortuary science that includes the natural organic reduction of human remains, also known as body composting.

“It’s a natural process where the body is returned to an elemental level over a short period of time,” said Viddal, who likened the practice to backyard composting of food scraps and yard waste. “This is the same process but done with a human body inside of a vessel, and in our case, in a controlled environment.”

On Sept. 7, Colorado became the second state after Washington to allow human body composting. Oregon will allow the practice beginning next July. In Washington, the three businesses licensed to compost human remains have transformed at least 85 bodies since the law took effect in May 2020, and more than 900 people have signed up for the service as natural funerals become more popular.

Viddal, who co-owns The Natural Funeral in Lafayette, lobbied the Colorado Legislature for the option and started building a prototype vessel in an industrial area soon after the bipartisan bill was signed into law.

Based on a design being used in Washington, the insulated wooden box is about 7 feet long (2 meters), 3 feet wide and 3 feet deep, lined with waterproof roofing material and packed with wood chips and straw. Two large spool wheels on either end allow it to be rolled across the floor, providing the oxygenation, agitation and absorption required for a body to compost.

Viddal calls the process an “exciting ecological option,” and in death, he also sees life.

“Composting itself is a very living function and it’s performed by living organisms. … There are billions of microbial, living things in our digestive tracts and just contained in our body. And when our one life ceases, the life of those microbes does not cease,” he said.

After about three months, the vessel is opened and the “soil” is filtered for medical devices like prosthetics, pacemakers or joint replacements. The remaining large bones are then pulverized and returned to the vessel for another three months of composting. Teeth are removed to prevent contamination from mercury in fillings.

The vessel must reach 131 degrees Fahrenheit for 72 continuous hours to kill any bacteria and pathogens. The high temperature occurs naturally during the breakdown of the body in an enclosed box.

In six months, the body, wood chips and straw will transform into enough soil to fill the bed of a pickup truck. Family members can keep the soil to spread in their yards, but Colorado law forbids selling it and using it commercially to grow food for human consumption and only allows licensed funeral homes and crematories to compost human bodies.

“It accomplishes the conversion of the body back into a very beneficial substance — soil, earth,” said Viddal, who envisions building more than 50 body composting vessels.

The Natural Funeral charges $7,900 for body composting, compared with $2,200 for flame cremation, and Viddal notes that a traditional burial and service in the Denver area can run well north of $10,000. The company has not yet composted any bodies, but several people have signed up and paid for the service.

AJ Killeen, 40, of Boulder, has already expressed interest in having his body composted when he dies, even though he is relatively young.

After a car accident a couple years ago, a doctor discovered Killeen had a heart condition. That got Killeen thinking about what would happen to his body after he dies, and composting seemed like a natural fit.

“It’s what’s going to happen anyway, right? I mean, we’re all going to turn to dust, basically. So this is just a little more natural,” he said. “They’re going to control the humidity. They’re going to control the soil amendments and hopefully some worms and some mushrooms find a good home in me for a few months. And, you know, at the other end of it, I’ll be just a few bags of dirt.”

Killeen, who manages commercial real estate, said his concern for the environment played a large role in considering the option. Flame cremation burns fossil fuels that can contribute to climate change, and the process also releases toxic, mercury-laden fumes into the atmosphere. Traditional burial takes up space in a cemetery that will use additional resources to keep the plot constantly watered and mowed.

“I always joke that I hope I expire on trash day if that’s just easier for my family,” said Killeen, who composts food scraps and yard waste through the city’s collection program.

Killeen is among a growing number of people considering more natural funeral options, especially since the pandemic began, and he thinks the option will become more accepted once people get over “the ick factor.”

The Colorado Catholic Conference, a group of bishops aimed at molding public policy, opposed the bill, saying body composting “does not promote human dignity.” Some rabbis also are against body composting because they say it violates Jewish religious law. Other opponents are concerned there is not enough research on whether the compost contaminates soil and there is no way to prevent people from using it in home vegetable gardens.

“We don’t know what they’re going to do with it if they take it all home,” said Stacey Kleinman, a board member of the Colorado Funeral Directors Association. They helped craft the legislation, but the group’s stance is neutral.

Even with the opposition, several states are considering the option as Americans become more open to afterlife alternatives.

According to a Choice Mutual Insurance Agency survey of 1,500 Americans this summer, when many were burying loved ones killed by the coronavirus, 21% said the pandemic changed how they want their body disposed of. Traditional burial and cremation remained the front-runners, but 11% said they would opt for burial involving natural decomposition without a casket. Only 4% said they would choose that option in a similar survey conducted in 2020.

Choice Mutual, which specializes in burial insurance, did not specifically ask about body composting, but the survey highlights an increased interest in more natural and environmentally friendly options.

Micah Truman, CEO and founder of Return Home south of Seattle, runs an 11,500-square-foot facility that includes 74 vessels. So far, his company has composted 16 bodies in what he describes as an “extremely precise scientific operation” that takes only 60 days.

Truman said that because the composting option is so new, “it’s really a matter of changing hearts and minds right now.” But he has been surprised by how many young people are interested, including someone who recently signed up their 8-year-old child.

“Our young people are going to teach us how to die better. It’s been really powerful for us,” Truman said. “I think what’s happened is that the younger generation really genuinely understands that we have to make sure that our Earth can stay whole.”