Washington state is on the verge of becoming the first in the US to allow humans to be turned into compost, amid a surge in demand for sustainable and 'positive' funeral services.

State representative put the final touches to a bill on Friday which legalises two sustainable death care options - a chemical process of alkaline hydrolysis and a natural process of organic reduction.

The bill has now arrived on the desk of Washington's governor and 2020 Democratic presidential candidate, Jay Inslee, who is expected to sign it into law within days.

The 68-year-old announced his bid for the presidency last month, highlighting his pro-environmental record as governor as he pitched himself as the only candidate committed to making tackling climate change their first priority in office.

Proponents of the human composting bill say an environmentally friendly after-death service is badly needed with an ageing population and as an alternative to costly burial services.

Katrina Spade and Dr Lynne Carpenter-Boggs Credit: WSU Communications / Recompose

One of those lobbying for the law change was Katrina Spade, founder of Recompose, who says the Seattle-based company plans to use wood chips, alfalfa and straw to turn bodies into a cubic yard of top soil in a month.

The soil can then be used by relatives to spruce up plants and trees in their gardens.

The company estimates that their natural recomposition process equates to more than one metric ton in carbon emissions savings per person.

“It is an understandable tendency to limit the amount of time we spend contemplating our after-death choices, but environmental realities are pressing us to develop alternatives to chemical embalming, carbon-generating cremation and the massive land use requirements of traditional cemeteries,” she said.

Artist's vision of a future Recompose facility Credit: Recompose

Ms Spade said her company was "overjoyed" to be able to launch in Washington soon and "a future where every human death helps create healthy soil and heal the planet".

The idea is likely to gain steam with the US approaching a historic spike in deaths as the baby boomer generation ages. According to the US Census Bureau, the annual death rate is projected to reach more than 3.6 million by 2037, one million more than in 2015, and the country's mortality rate will continue to "increase dramatically every year" until 2055.

The alternative death-care movement has already seen a boom in companies offering non-traditional services, from turning ashes into jewellery to hosting life "celebration" parties instead of dreary funeral services.

Traditional, somber burial services may become a thing of the past Credit: RubberBall Productions

Amy Pickard started up Good to Go - a death planning "party service" - in Los Angeles after the sudden death of her mother in 2012 left her wishing for a "manual" to help her navigate the emotional and financial upheaval.

"I decided that I didn't want everyone to go through the hell that I went through," she told The Telegraph. "I wanted to do it in a fun, casual way to target people when they're relatively young and healthy and go through it in a party-like atmosphere."

Ms Pickard said her parties address issues that aren't covered in a traditional will or trust, such as passwords to online billing accounts or social media profiles.

"It's those little details that when you're grieving you want to have the brain space to process without having to be a detective and a party planner".

Ms Pickard uses the gatherings for clients to go through a 60-page booklet which covers everything from what you want done with your diaries to your views on love and forgiveness.

"With a sense of humour and positive attitude we go through the paperwork and talk about the tough discussions that people don't talk about," she said. "That's what the death-positive movement is all about - you're not positive about death but you have to accept it's part of life."

Ms Pickard has had confirmation of how useful her parties can be - her father John held one just a year before he fell ill. "I had to make the call to take him off life support. I didn't feel one ounce of guilt because I knew that was exactly what he wanted," she said.

Ms Pickard said that to celebrate her father's love of animals she threw a 'John Voyage' party featuring baby animals on loan from a sanctuary. "How can you be sad around baby animals? There are no rules in 2019," she said.

"I think people are feeling a lot more enabled to do whatever they want for a life celebration or funeral".