Ameren Illinois Utilities has made no secret about what’s going on under those big white tents just blocks away from the Capitol.
As has been widely reported, the utility company is excavating the remnants of a manufactured-gas plant that operated there from 1854 until the 1930s and removing coal tar, a byproduct of the process, left in the ground when the facility ceased operation.
But what exactly is coal tar and is it harmful to people or the environment? “It had an economic value and still does. You’ve probably used coal tar in the past week if not the past day,” says Ameren spokesman Leigh Morris.
Coal tar is a fairly common ingredient in products ranging from dandruff shampoo to medicines, such as Tylenol — but that’s not to say it’s good for you.
Steven Burns, an Ameren environmental scientist, explains: “It’s like asking us if gasoline is good for you. Well, yeah, it’s great for you, but I wouldn’t want to drink it or eat it.
“Coal tar is useful and it’s a good product but even table salt could be harmful if used improperly.
Anything that you ingest, if you ingest it in excess quantities or improperly,
can be harmful.”
Among the potentially harmful chemicals contained in coal tar are polynuclear aromatic hydrocarbons (PAHs), volatile organic compounds, sulfur, cyanide and a carcinogen found in cigarette smoke called benzene. PAHs, Ameren officials explain, are emitted as a result of natural and man-made combustion processes like forest fires and barbecuing
Manufactured gas plants were symbols of modernity in their heyday. By heating oil and coal, MGPs generated gas for lighting homes and streetlights, heating and cooking until the discovery of cheaper, cleaner and more abundant natural gas in the mid-20th century.
Afterwards, many of the facilities were abandoned or demolished, leaving behind a mix of bricks, mortar, dirt and coal tar.
Cleaning up the mess often presents challenges. The current downtown remediation site, for example, has seen several ownership changes over the years. Ameren acquired the land when the company took over Central Illinois Light Company in 2003. Often, the presence of former MGP locations are unknown until real estate developers begin work. Of the 3,000 to 5,000 facilities built in the U.S., only about 80 percent have been identified.
In 2005, AmerenCILCO conducted soil testing at the First and Washington property (another former site, also owned and eventually remediated by Ameren, was located on North MacArthur Blvd.) revealed the presence of coal tar, or source material. After several rounds of soil testing and submitting the results and work plans to the Illinois Environmental Protection Agency, Ameren started the downtown excavation last summer.
Work crews removed 7,500 tons of material in the initial stage of the project.
To begin the next phase, a second temporary tent was erected last week. The remediation is expected to be finished by April 2009 and will cost $6 million,
some of which the Illinois Commerce Commission permits Ameren to recoup with a
small environmental “rider” charge on the utility company’s natural gas customers.
So far, the Springfield cleanup effort has received high marks from the Illinois Environmental Protection Agency, which can issue Ameren a “no further remediation” letter once the work is complete.
Stan Black, an IEPA community relations coordinator, bolsters Ameren’s public claims that people aren’t in harm’s way, explaining that the coal tar is located approximately 15 feet
underground, which reduces the possibility of human contact. Additionally, the
site has been capped, covered by asphalt and buildings, for many years. And no
drinking water comes from the groundwater.
“So there was no immediacy in terms of having to get in and clean up [the] site,” Burns says.
The purpose of the 48-foot-tall tents, he adds, is to protect work crews from the elements and to mitigate odors that might be produced during the unearthing of chemical residues — not to be secretive.
“We don’t want the public to think we’re trying to hide anything because we put a tent up,” Burns says. “We do this because we’re concerned about the public and we want to protect our neighbors and do things
This includes posting ambient air monitoring reports on site and keeping records on file for public viewing at Lincoln Library’s Sangamon Valley Collection.
But despite being thick, viscous and slow-moving, coal tar can migrate slowly over long periods of time. “This is not like water — it’s more like molasses. It does need to be removed but it’s under the ground. In this case it’s many, many feet under the ground,” Ameren’s Morris says.
However, new signs of contamination have recently been discovered just east of the remediation site, approximately 20 feet below the surface. But it is unclear whether further remediation is needed.
“At the moment, we don’t see it representing any kind of public health risk so no decision has been
made on that,” the IEPA’s Black says. “We do know that if we find anything [substantial], they will have to take care
Ameren has plans for approximately 40 MGP remediation projects around the state, which the company expects to conclude by the end 2015. In total, around 20 such projects are in some stage of cleanup or site investigation statewide.
Material that is not classified as hazardous is being taken to a Springfield landfill, while the coal tar will be shipped to the nation’s largest hazardous waste dump in the Alabama town of Emelle.
Contact R.L. Nave at firstname.lastname@example.org