Review points to fewer toxic chemicals in ethanol-blended gasoline emissions


A newly published review of top scientific literature suggests that ethanol-blended fuels widely available at gas stations as E10, E15, or E85 result in less toxic emissions from vehicles and present a lower risk to human health than regular gasoline. The study, a collaboration between The Hormel Institute, University of Minnesota and the Energy Resources Center, University of Illinois Chicago, shows that gasoline containing ethanol produces lower emissions of toxic chemicals known to cause cancer.


The work was supported in part by the Renewable Fuels Association and The Hormel Institute.

“Research into this area is critically important because the environmental factors that affect cancer risk are not well understood and may have a huge impact on cancer promotion and progression,” said Dr. Shujun Liu, Assistant Director and head of the Cancer Epigenetics & Experimental Therapeutics section at The Hormel Institute.


“We need to do everything we can to reduce related cancer risks to protect human health. Advancing research and understanding such as this is our responsibility and will be an ongoing effort.”


The review article, “An Assessment on Ethanol-Blended Gasoline/Diesel Fuels on Cancer Risk and Mortality,” was published in the International Journal of Environmental Research and Public Health (2021) by Dr. Steffen Mueller of the Energy Resources Center and Dr. Shujun Liu and Gail Dennison of The Hormel Institute. It reviews research on the toxicity of gasoline and expected toxicity reductions with ethanol.


The review focuses on carcinogens, or substances capable of causing cancer, and epigenetics, or how behaviors and environment can affect how your genes work, and the impact of biofuels on each. According to the National Cancer Institute, people can avoid some cancer-causing exposures, such as tobacco smoke and the sun’s rays, but others are harder to avoid if they are in the air we breathe, the water we drink, the food we eat, or materials in the workplace.


Epigenetic abnormalities, including DNA hypermethylation, histone deacetylation, and/or microRNA dysregulation, have been demonstrated as a hallmark of cancer. Compared with gene mutations, aberrant epigenetic changes occur more frequently, and the cellular epigenome is more susceptible to change by environmental factors. The research suggests cancer risks are positively associated with exposure to occupational and environmental chemical carcinogens, including those from gasoline combustion exhausted in vehicles. The toxicity of chemical agents has been thoroughly studied,  however less effort has been put into studying the epigenotoxicity (e.g., aberrant DNA methylation that may lead to cancer).


Refiners blend aromatic hydrocarbons into gasoline to prevent the fuel from premature combustion (known as knocking), but ethanol has similar or superior anti-knock properties and is used as a substitute. As the blending of ethanol into gasoline substitutes for these carcinogens like benzene, toluene, xylene, and polycyclic aromatic hydrocarbons, cancer reductions are expected. In their regularly released Fuel Trends Reports the U.S. Environmental Protection Agency specifically states that “ethanol’s high octane value has allowed refiners to significantly reduce the aromatic content of the gasoline.” The present study finds that this may lead to diminished cancer risk through an altered cellular epigenetic landscape.


The review summarizes the most important findings in the literature on the association between exposures to carcinogens from gasoline combustion, cancer epigenetics and the potential epigenetic impacts of biofuels. While the authors concluded that the available research points to biofuels containing fewer carcinogens and therefore reduced cancer risk, larger exposure studies are still needed to confirm the results.


“I’m excited to see the research point to what we’ve suspected after years of working in this field – that replacing aromatics with ethanol indeed can have a direct positive impact on human health,” said Dr. Steffen Mueller, Principal Economist at the Energy Resources Center, University of Illinois, Chicago. “To further protect people from the unnecessary promotion of diseases like cancer, it is critical to continue research that examines the human health effects of these emissions.”


The full review article can be accessed through this link:

International Journal of Environmental Research and Public Health is an interdisciplinary, peer reviewed, open access journal published semimonthly online by MDPI. It covers Environmental Sciences and Engineering, Public Health, Environmental Health, Occupational Hygiene, Health Economic and Global Health Research.


About Dr. Shujun Liu and The Hormel Institute:


Dr. Liu has been at The Hormel Institute since 2011 and was recently awarded a $4 million grant to research leukemia by National Institutes of Health and this year was named Assistant Director for Research for The Hormel Institute. Dr. Liu’s research focuses on the role of receptor tyrosine kinases and epigenetics in cancer development, progression, and drug resistance, primarily in leukemia. The Hormel Institute is an independent biomedical research department within the University of Minnesota’s Office of the Vice President for Research. Collaborative research partners include Masonic Cancer Center UMN (a Comprehensive Cancer Center as designated by the National Cancer Institute, N.I.H.), the Mayo Clinic (US News & World Report’s “Best Hospital in the United States”), and renowned research centers worldwide. The Hormel Institute tripled in size in 2008 and again doubled in size in 2016 and is home to some of the world’s most cutting-edge research technologies and expert scientists. Over the next few years, The Hormel Institute will broaden its impact through innovative, world class research in its quest to improve human health.


About Dr. Steffen Mueller and the University of Illinois, Chicago:


Dr. Mueller leads the Bioenergy and Sustainable Landscapes Research Group at the University of Illinois Chicago’s Energy Resources Center. Research activities focus on life cycle emissions analyses of fuel pathways including greenhouse gas emissions assessments from land use change related to biofuels and bioenergy production, quantification of carbon emissions and sequestration effects from production agriculture, and comparative emissions assessments between biofuel and electric vehicle use. Steffen has also performed numerous feasibility studies and technology evaluations in the biofuels and bio-products area. Dr. Mueller has published over 25 peer reviewed papers on life cycle emissions analysis and he is a co-author of the land use change interface of the Argonne National Laboratory GREET model. Steffen served on the Expert Working Group for the California Low Carbon Fuel Standard development in 2010 and he presented his biofuels research results to the White House Council of Economic Advisors in 2014.


Ken Colombini