Blue Ocean Barns will supply some dairy farms in California with a feed supplement made from dehydrated red seaweed. The state’s Department of Food and Agriculture approved the product for commercial use last month. Blue Ocean claims the supplement reduces methane emissions from cow burps by 45–80%. The company has been growing seaweed at commercial scale since 2020. Last fall DSM introduced the additive 3-nitrooxypropanol, which it says reduces methane emissions by 30%.