On Tuesday, Washington state Governor, Jay Inslee, signed legislation to become the first state to legalize “human composting,” an alternative to conventional burial and cremation that produces topsoil suitable for gardening.

The practice is described by proponents as an eco-friendly form of final disposition. Inslee, a Democrat, is making climate change the focus of his presidential campaign, and advocates calculate that natural organic reduction — as composting is more delicately termed — will save about a ton of carbon emissions for each body.

The law, set to take effect May 1, 2020, paves the way for a Seattle business to build the nation’s first funeral home offering the service. The company, called Recompose, will place bodies in steel vessels with wood chips, alfalfa and straw, enabling microbes to break down bodies into soil in about a month.

Recompose plans to charge about $5,500, more than no-frills cremation and less than burial in a casket. The company’s chief executive, Katrina Spade, said Tuesday that she hoped to open a Seattle outlet by the end of next year. “This will be the first place that we know of in the world where this option will be offered to people,” she said.

The bill authorizing the practice passed Washington’s legislative chambers with bipartisan majorities. But the Catholic Church opposed the measure, maintaining that composting did not show sufficient respect for the deceased.

Washington’s funeral industry is split concerning the practice, but history has shown that undertakers can change their views. Nationally, many funeral businesses traditionally opposed cremation, but the practice of reducing bodies to ashes began gaining acceptance during the 1960s and now accounts for about half of dispositions.