The Renewable Fuels Association provided comments this week in response to a request for information from the California Air Resources Board, urging them to do more to ensure the integrity of imported used cooking oil (UCO) and tallow for biomass-based diesel production under the state’s Low Carbon Fuel Standard.

According to CARB data on fuel consumption in California, usage of biomass-based diesel (BBD) produced from UCO doubled from 2019 to 2023, while usage of BBD produced from tallow tripled, RFA noted, and some in the marketplace believe these feedstocks may be of questionable origin and content.

“Many biofuel market participants and other observers have expressed concerns about the legitimacy of imported ‘waste’ feedstocks and have questioned whether some volumes of UCO in particular may contain palm oil and/or other incorrectly labeled fats, oils, and greases,” wrote RFA Chief Economist Scott Richman. “These concerns have been heightened in recent months as Indonesia and Malaysia, which jointly account for nearly 85% of world palm oil production, have emerged alongside China as leading origins of UCO imported into the U.S.”