Gopher State Ethanol
Note: This plant closed on May 14, 2004.
September 19, 2003
This web site provides general information about public health issues related to the Gopher State Ethanol plant in St. Paul for people living near the plant and others who may be interested. It does not provide a comprehensive discussion of all available technical information about the site, or all health issues that have been raised in connection with the site. More detailed information is available in the Gopher State Ethanol - Public Health Assessment.
On this page:
What is the history of the site?
How is ethanol made? Where do the emissions come from in the ethanol process?
What are the health concerns? What is being done in response?
Volatile organic compound emissions
What does MDH recommend?
Where can I get more information?
MDH comments to the U.S. Department of Justice on the Proposed Consent Decree
In the fall of 2000 the Minnesota Brewing Company expanded its facility located in the West Seventh Street neighborhood near downtown to include ethanol production. Ethanol, or grain alcohol, can be made from corn and can be added to gasoline for use as fuel. In response to numerous community complaints about odors and reported health effects, the Minnesota Pollution Control Agency requested that the Minnesota Department of Health investigate and evaluate the possibility of health effects caused by emissions from ethanol production. MDH has made a number of site visits to both the brewery and ethanol plant, including roof top observations of various emission points. The plant is located in a densely populated area of the city with several schools nearby.
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Trucks transport corn to the ethanol plant. Dust generated by the unloading process is drawn into a pit and removed by a fabric filter. The corn is then cleaned, milled, and cooked. The resulting mash is pumped to the fermentation tank where the sugars are changed to ethanol. The gases coming from the fermentation tanks are sent through a water scrubber that removes ethanol and separates out carbon dioxide. Two carbon bed units remove impurities in the carbon dioxide. The mash is distilled to remove the ethanol from the mash. This process vents through a scrubber but still produces odor. The final step is to concentrate the ethanol by removing water.
After removing 90% of the ethanol and water from the mash, the remaining liquids are separated from the solids by spinning. The solids are heated with hot air in the Distillers Dried Grain Solids (DDGS) dryer. Several cyclones (a device that spins the air and dried grain to force dust out) reduce the amount of particulates released into the air. The gasses from the cyclones are sent to the thermal oxidizer to be burned and then released into the air.
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Citizens have complained about health effects that they believe are from odorous or irritating volatile gaseous emissions and dust particles.
Volatile organic compounds (VOCs) are a group of chemicals that evaporate easily into the air. The ethanol production process gives off a complex mixture of VOCs. VOCs from the DDGS dryer, cooling cyclone, centrifuge and carbon beds are sent through a control device called a thermal oxidizer that destroys greater than 90% of the emissions at 1400 °F. Though people are exposed to stack emissions through the air, the amounts of VOCs found in the tested stacks at the plant do not exceed health limits used by MDH to evaluate possible health impacts. The testing shows the maximum amount of chemicals that would be released into the air when every part of the control system was functioning properly. MDH is concerned that if there are periods of operation when the control system malfunctions or is bypassed then health limits may be exceeded. Another concern is that other sources of VOCs have been added to the intake to the control system since the first testing, and the testing results of that change are not yet available. It is also possible that some gasses could escape through the fresh air intake unintentionally. Because of these concerns, MDH would like to see more frequent testing than the current five-year cycle.
Odor is not always related to a chemical's toxicity. Some chemicals can be detected by the human nose at levels far below where there could be any adverse health effect. Other chemicals are harmful before they can be detected by smell. Amounts of chemicals in the air that can cause harm to health may or may not be accompanied by odor. Aside from other effects of the chemical, the odor itself can cause health effects such as headaches, nausea, cough, congestion, shortness of breath and eye, nose and throat irritation. Odors can also become associated with health effects even when a toxin is not present; for reasons not fully understood, odors can still produce health effects. The thermal oxidizer reduces but does not eliminate odors.
Fugitive emissions are gasses that escape without any controls or evaluation. The Minnesota Brewery and the Gopher State Ethanol plant have stacks and roof vents that have not been evaluated by the MDH or MPCA. Extensive plumbing and pipes have been added and modified through the years. Gasses that accumulate in buildings may drift across the street. These fugitive emissions are also a continuing source of odors. A long-term plan is needed to systematically document and control fugitive emissions.
On two occasions, there have been accidental releases of anhydrous ammonia. One required evacuation of the buildings and 18 people were taken to the hospital. A risk management plan that includes both the brewery and the new ethanol plant needs to be developed and placed on file with the Minnesota Department of Public Safety.
Testing of the grain cooler stack and the baghouse stack during normal operation found them to be in compliance with the facility permit. However, area residents occasionally complain of yellow dust on windowsills, roofs and cars in the morning after they have been parked outside overnight. There have been several "eruptions" of the cooling cyclone that blew grain across the street to a distance of several blocks. There is an accumulation of corn dust on the roof of the plant, especially around the cooling cyclone. Process design changes have eliminated the cooling cyclone as a source of particulates.
The plant has a history of violations of the nighttime noise standard. The city and the plant have agreed to a settlement that requires the sources of noise to be identified and the city nighttime noise standards to be met. Efforts have been made to reduce the noise, but the plant is still not meeting the nighttime standard.
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- The thermal oxidizer should be tested at least two separate times before the next required test in five years.
- A careful study of fugitive emissions should be done to identify sources of chemical irritants, odors and particulates from both the plant and the brewery.
- Known sources of odorous gases and particulates should be sent through the thermal oxidizer, or otherwise mitigated.
- A risk management plan that includes the new ethanol plant should be submitted to the city of St. Paul and the Minnesota Department of Public Safety.
- Noise violations should be eliminated.
- Reports submitted to the MPCA and the MDH should also be given to the West 7th Federation, a citizens' group.
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MDH's Comments to the U.S. Department of Justice on the Proposed Consent Decree (Nov. 18, 2002): United States et al. v. Gopher State Ethanol, Inc.
D.J. Ref. 90-5-2-1-07784/8
Comments to Proposed Consent Decree (PDF: 95KB/3 pages)
Pursuant to 28 CFR Section 50.7 and the Federal Register notice of October 24, 2002 (Volume 67, Number 206, Page 65365, the Minnesota Department of Health (MDH) commented on the proposed Consent Decree (CD) in United States et al. v. Gopher State Ethanol, Inc.
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This information sheet was prepared in cooperation with the U.S. Agency for Toxic Substances and Disease Registry.