Manufactured Gas Plants
What is a former manufactured gas plant (MGP)?
During the 1800s, towns and cities across the U.S. made their own fuel
for electricity. The fuel was produced at a manufactured gas plant (MGP).
This fuel was used to light the home, business and street lamps. To
manufacture the fuel, coal and other ingredients were heated in large
brick ovens. As the coal was heated, it produced a gas. The gas was
filtered from the ovens and stored in tanks. The gas was then used as fuel
throughout a community. By the early 1900s, Wisconsin had at least 70 MGP
sites across the state.
MGP production declined as a network of natural gas pipelines was built
across the country in the 1950s. As natural gas became widely available,
MGPs closed. It was cheaper to use natural gas. Many MGPs were abandoned
and eventually demolished. However, waste and contamination from MGPs
still pose an environmental and public health concern.
Why be concerned about wastes from an MGP?
Manufacturing gas from coal generated a lot of waste. Typically, the
coal waste was dumped in nearby ravines, ditches or used as fill for
construction projects. Today much of the waste is found to be hazardous.
The waste includes cyanides, metals, solvents and oily tars.
The oily tars are made of organic chemicals called
hydrocarbons (PAHs). PAHs commonly found at MGP wastes are may also cause
cancer in humans.
Can an MGP site be a health hazard? Can it affect my drinking water?
Waste from the gas manufacturing processes can be found in soil,
surface water, and ground water. Depending on the site, the contamination
can be minimal or extensive. Most of the contamination is buried under
soil and does not pose a direct health risk. However, if coal tar residues
come in contact with skin, it can cause redness or a rash. In some people,
the coal tar can cause a sunburn effect on skin. Eye irritation is another
hazard if coal tar residues get in the eyes.
In cases where the contamination has spread into groundwater, exposure
to drinking water contaminants can be a concern. Tests can be performed to
determine if water quality is affected by a former MGP. Fortunately,
drinking water contamination is not a common problem from MGP sites.
What is being done about old MGP sites?
In cooperation with local governments, the Wisconsin Department of
Natural Resources (DNR) and the Department of Health Services (DHS)
are working to address and clean up former MGP sites. Some former MGP
sites are cleaned, others are in the process of being cleaned or have
clean up planned.
Various methods are used to clean up a site. Some sites use a method
that heats up the contaminated soil and allows quick removal of
contaminants. This technology reduces the need for transportation and
disposal of contaminated soil offsite, making the clean up more efficient
and cost effective. Other methods use a series of extraction wells that
pump the coal tars from the ground into holding tanks. The coal tars are
then transported off the site. The coal tar is then either burned as fuel
or dumped at an approved landfill.
What are the health concerns of cleaning up former MGP sites?
Cleaning up a MGP site may temporarily cause discomfort to a
neighborhood. The clean up problems include odors, noise and the presence
of heavy machinery. Odors are the most commonly reported nuisance. The
odors that may occur can have either a gasoline or mothball-like smell.
People with breathing difficulties, such as asthma, may be affected if the
odors reach hazardous levels.
The contractors cleaning up a MGP site are trained to manage the site
for safety. They also monitor and control vapors from reaching levels of
health concern to nearby residents. Because workers
are frequently close to the contamination, they sometimes wear special
protective clothing and use protective equipment, including supplied air,
during clean up work. DHS actively works with the
site clean up team to ensure that odors and other discomforts minimally
affect a community.
What actions can I take?
- Report any concerns, such as noise or odor complaints directly to
the site clean up contractors or DNR staff.
- If you live near a former MGP and have a well, consider testing the
water. The water test should look for
volatile organic chemicals (VOCs)
and chlorinated solvents.
- Attend public meetings related to the MGP site in order to get
- Ask questions at the meeting directly to DNR,
contractors, or health department staff.
For more information
- For health related questions, contact the Division of Public Health, Bureau of
Environmental and Occupational Health,
PO Box 2659, Madison, WI 53701-2659, (608) 266-1120
- Questions and link to the Wisconsin
- DHS Health-based
Guidance for regulatory agencies, environmental consultants and
contractors on MGP site clean up, community outreach and risk
June 10, 2014