Swiss company Climeworks announced Thursday that it has successfully taken carbon dioxide out of the air and put it in the ground where it will eventually turn into rock in a process that has been verified by an independent third-party auditor. It the first time a company has successfully taken carbon dioxide out of the atmosphere, put it underground to be locked away permanently and delivered that permanent carbon removal to a paying customer.

The development has been a long time coming. Christoph Gebald and Jan Wurzbacher co-founded Climeworks in 2009 as a spinoff of ETH Zürich, the main technical university in Switzerland’s largest city. They have been scaling the technology for direct carbon removal, wherein machines vacuum greenhouse gasses out of the air.

Over the last couple of years, Microsoft, Stripe and Shopify have all bought future carbon removal services from Climeworks in a bid to help kick-start the nascent industry. Now Climeworks is actually removing the carbon dioxide and putting it underground in a process that has been certified by DNV, an independent auditor.

The cost of carbon dioxide removal and storage for these corporate clients is confidential and depends on what quantity of carbon dioxide the companies want to have removed and over what period of time. But the general price for carbon removal runs to several hundred dollars per ton. Individuals can also pay to Climeworks to remove carbon dioxide to offset their personal emissions.

In addition to getting corporate clients to pay for future removals, Climeworks has raised more than $780 million to scale up from a wide variety of investors including venture capitalist John Doerr and insurance company Swiss Re.

Climeworks’ largest carbon dioxide removal facility is located in Iceland, where it partners with CarbFix, which stores the gas underground. CarbFix dissolves carbon dioxide in water then intermingles that mixture with basalt rock formations. Natural processes convert the material to solid carbonate minerals in about two years.

In June, Climeworks announced it had begun construction of its second commercial-sized plant in Iceland that will capture and store 36,000 metric tons per year of carbon dioxide. Even when complete, that will amount to a tiny percentage of the total global emissions of carbon dioxide released into the air each year: In 2021, they hit a record high of 36.3 billion metric tons, according to the International Energy Agency.