State representatives made final touches to the bill, which would permit residents to have their remains disposed of using "organic reduction", on Friday.
Two sustainable death care options are set to be legalised - a chemical process of alkaline hydrolysis and a natural process of organic reduction, according to The Telegraph.
The bill references research claiming that human compost would be safe to use in residential gardens and would not smell like anything other than soil.
Inslee spokeswoman Jaime Smith said that while the governor’s office is still reviewing the bill, “this seems like a thoughtful effort to soften our footprint” on the Earth. @GovInslee we think so, too. https://t.co/dYuE1YD5bx pic.twitter.com/kIkgM13rwI— Katrina Spade (@recomposelife)22 April 2019
Proponents of the bill say it’s an environmentally friendly alternative to expensive after-death services, and is badly needed with an ageing population.
Katrina Spade, founder of Recompose, says the Seattle-based company will use wood chips, alfalfa and straw to turn bodies into a cubic yard of top soil in a month.
Relatives can then use the compost to nourish plants and trees in their gardens, and the company estimate that the process equates to more than one metric ton in carbon emissions saving per person.
Ms Spade told The Telegraph: “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 Recompose was "overjoyed" to be able to launch in Washington soon for “a future where every human death helps create healthy soil and heal the planet".
The bill has reportedly 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.
He has pitched himself as the only candidate committed to making tackling climate change their first priority in office.