Despite its green image, the biofuels industry releases a surprising amount of hazardous air pollution that puts local communities at risk – and this problem is exacerbated by EPA’s lax regulation. EPA needs to end its permitting loopholes for large ethanol plants and start requiring the kind of fenceline air pollution monitoring and cleanup actions the agency already requires for oil refineries.
… said Courtney Bernhardt, Director of Research for the Environmental Integrity Project
EIP’s report found that, despite government policies supporting the biofuels industry, biofuel plants frequently violate their air pollution control permits, releasing illegal amounts of contaminants that threaten the health of downwind communities. Biofuel plants also emit large quantities of greenhouse gases for an industry that portrays itself as climate-friendly.
For this report, EIP examined the public records of 191 ethanol manufacturing plants, 71 biodiesel plants, and 13 “renewable diesel” plants in the U.S. – as well as permit applications for dozens of new facilities and expansions – and reached the following conclusions:
- Hazardous air pollution: Despite their “green” reputation, biofuel factories release almost as much hazardous air pollution as oil refineries, with biofuel plants reporting they emitted 12.9 million pounds of hazardous air pollutants in 2022 (the most recent available year) and oil refineries 14.5 million pounds, according to reporting to EPA’s Toxics Release Inventory.
- 4x more of four pollutants: Biofuel manufacturing plants reported releasing significantly more of four hazardous air pollutants. The biofuel plants reported emitting 7,698,860 pounds of hexane in 2022 (compared to 2,630,758 from oil refineries); 2,117,953 pounds of acetaldehyde (compared to 10,420 from refineries); 357,564 pounds of acrolein (compared to zero from refineries); and 235,125 pounds of formaldehyde (compared to 67,774 from refineries).
- Acrolein: More acrolein is emitted from the biofuels industry than any other industry in the U.S. And the Cargill Inc. ethanol plant in Blair, Nebraska, was the single largest emitter of acrolein in the U.S. in 2022, regardless of industry, reporting the release of 34,489 pounds of a chemical that can cause shortness of breath and irritate the lung and eyes.
- Hexane: The Archer Daniels Midland (ADM) ethanol and grain processing plant in Decatur, Illinois – one of the largest ethanol factories in the country – was the single largest emitter of hexane in the U.S. in 2022, regardless of industry, releasing 2.2 million pounds of a pollutant that can damage the nerves and cause dizziness and nausea.
- Frequent violations: More than 41 percent of biofuels plants (98 of 240) violated their air pollution control permits at least once between July 2021 and May 2024, according to a review of EPA’s Enforcement and Compliance History Online database.
- Failed smokestack tests: Sixty-five out of 182 biofuel plants with available data (36 percent) failed “stack tests,” over the last five years, which measure the amount of a pollutant to determine if emissions are in compliance with the Clean Air Act.
- Climate impact: In terms of climate-warming pollution, biofuel plants in the U.S. reported emitting over 33 million metric tons of greenhouse gases in 2022 – as much as 8.5 coal-fired power plants burning fuel around the clock or 27.5 average oil refineries.
- Rapid growth: After quadrupling the number of biofuel plants in the first decade of this century, the industry continues to grow – with at least 32 new or expanded biofuels facilities now under construction or proposed that would increase biofuel capacity by another 33 percent over 2023 levels. About two thirds of these new facilities and expansions are for “sustainable aviation fuel” that may include jet fuel made from wood or plants.
EIP’s report found that ethanol manufacturing plants enjoy some exemptions from air pollution permitting requirements, making it easier for companies to expand or build new facilities without installing or upgrading pollution controls to reduce emissions of health-damaging air pollutants.
In 2007, EPA removed corn-based ethanol plants from a list of industrial facilities subject to more stringent emission thresholds under the Clean Air Act. As a result, these ethanol plants can emit more than twice as much pollution – up to 250 tons per year instead of 100 tons per year – before they must obtain a major source permit that requires stronger pollution controls.
To address the pollution problems from biofuel manufacturing plants, EIP’s report makes the following policy recommendations:
- End permitting exemptions for ethanol: EPA should reverse its 2007 decision to relax major source permitting thresholds for ethanol manufacturers that allow these plants to emit more than twice the level of air pollution before needing to install better pollution controls.
- Better monitoring and control of pollutants: EPA should require large biofuel plants to install air pollution monitoring devices along their fencelines to detect the levels of hazardous air pollutants, like acetaldehyde and acrolein, that could be drifting into nearby communities. EPA should also establish an ‘action level’ for these and other highly toxic pollutants, that, if exceeded, would obligate these facilities to identify the sources of the emissions and then fix the problems causing elevated concentrations.
- Stronger enforcement of permits: EPA and state regulatory agencies should more vigorously enforce air pollution control permits for biofuel plants, imposing penalties large enough to discourage future violations and protect downwind communities.
- Improve the accuracy of emissions reporting: Biofuels producers should be required, during the permit review and approval process, to expand their emissions testing and improve the accuracy of their pollution reporting to both EPA and the states.
- End biofuel subsidies and mandates: Biofuels are growing at a rapid rate in part because of government funding and regulatory mandates for blending ethanol into gasoline. But the environmental benefits of these government supports are questionable at best. All existing subsidies and mandates for ethanol – including the renewable fuel standard – should be halted – and attention focused instead on clean energy sources like solar and wind and the infrastructure needed to support them.
