Heirloom Carbon (NSF-2112424) uses limestone to capture carbon dioxide directly from the atmosphere and stores it underground or in long-lasting materials. The company recently partnered with Microsoft to remove up to 315,000 metric tons of CO2 — one of the largest carbon-removal deals ever, according to The Wall Street Journal. <a hre"https://www.wsj.com/us-news/climate-environment/microsoft-will-use-carbon-absorbing-rocks-to-meet-climate-goals-57ea802a">Article via The Wall Street Journal</a>