 Hazardous
Waste Sites in Minnesota
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 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
Contacts
What is the history of the site?
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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How is ethanol made? Where do the emissions
come from in the ethanol process?
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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What are the health concerns? What
is being done in response?
Citizens have complained about health effects that they believe are
from odorous or irritating volatile gaseous emissions and dust particles.
Volatile organic compound emissions
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.
Odors
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 and Accidents
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.
Particulates
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.
Noise
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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What does MDH recommend?
- 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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Where can I get more information?
A copy of the Gopher State Ethanol Public Health
Assessment is available. You may request a copy from the MDH by
contacting Tannie Eshenaur at the phone number listed below.
MDH's Comments to the Proposed Consent Decree (Nov. 18, 2002) (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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Contacts:
MDH Health issues Rita Messing 651.201.4916 health.hazard@state.mn.us
MDH Health education Tannie Eshenaur 651.201.4897 health.hazard@state.mn.us
This information sheet was prepared in cooperation with the U.S.
Agency for Toxic Substances and Disease Registry.
For more information about this page, please contact us at health.hazard@state.mn.us call 651-201-4897, or toll-free 1-800-657-3908 and press "4" to leave a message.
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