By Fabio Teixeira, Manuela Andreoni and Allison Lampert
XINGUARA (Reuters) -A Texas refinery that supplies green fuel to U.S. airlines has been purchasing animal fat from cattle raised on illegally cleared lands in the Amazon rainforest, according to a Reuters review of government tracking data, interviews and eyewitness accounts.
Louisiana-based Diamond Green Diesel, a joint-venture between biofuels producer Darling Ingredients and petroleum refiner Valero Energy, has invested hundreds of millions of dollars into a refinery in Port Arthur, Texas that turns cattle fat – called tallow – into a cleaner alternative to petroleum-based jet fuel and diesel.
Diamond Green Diesel is a major player in the U.S. sustainable fuels market. It has collected over $3 billion in U.S. tax credits for producing biofuels since 2022, according to filings.
But interviews and documents show at least two Brazilian factories that supplied Diamond Green Diesel with tens of thousands of tons of cattle fat since 2023 are sourcing some of it from slaughterhouses that have bought animals from illegally deforested ranches in the Amazon rainforest.
Carriers such as JetBlue and Southwest Airlines, which struck deals with Valero to use the “green” jet fuel, can claim credit for lowering their emissions because Diamond Green Diesel’s plant is certified under a United Nations agreement curbing the impact of aviation on the climate called CORSIA.
The global market for sustainable jet fuel is small, about $2.9 billion in 2025 according to analysis firm SkyQuest Technology Group, compared to the $239 billion global market for conventional aviation fuel. But government incentives are expected to help the market grow exponentially, pumping more resources into the Brazilian cattle industry, the leading driver of the destruction of the Amazon rainforest.
Pedro Piris-Cabezas, an economist at the nonprofit Environmental Defense Fund, said any additional demand “could result in the expansion of herds and directly or indirectly drive deforestation and forest degradation.”
It could also violate Brazilian law. “Companies that profit from raw materials originating from a supply chain that involves deforestation, are also responsible for these illegalities,” said Ricardo Negrini, a Brazilian federal prosecutor who has opened a number of government investigations into the cattle industry.
Diamond Green Diesel, Darling Ingredients, Valero Energy, Southwest and JetBlue did not reply to multiple requests for comment, including detailed questions about the Brazilian tallow supply chain.
