CHAMPAIGN – A voluminous new report from Ameren says the public's health is not immediately threatened by underground contamination at a former coal gasification plant in north Champaign.
But test results in the report show contaminants in the soil, including benzene, have spread beyond the AmerenIP site to the north, west and east – and possibly to the south. And at least one groundwater well just west of the property, and others on the site itself, are contaminated with benzene, a known carcinogen, and other byproducts of the manufacturing process.
The utility and its consultants concede further testing is needed to find out how far the contaminants extend from the 3.5-acre site along Fifth Street, between Washington and Church Streets. While groundwater is tested quarterly, the latest soil tests are from 2004.
They plan to take more soil and water samples in coming months, as soon as the Illinois Environmental Protection Agency completes its review of the report. Stan Black, community relations coordinator for the IEPA, said the agency has 60 days to respond, which would be mid- to late February.
Black agrees there's no "imminent health threat" because the public isn't directly exposed to the underground contaminants.
This initial site investigation report isn't meant to discuss risks so much as lay out exactly what contaminants remain in the ground from the coal gasification process, he added. Later reports will detail what action needs to be taken.
The plant operated from at least 1887 to 1955, manufacturing gas from coal for heating and lighting. The process heats coal and causes it to react with steam to produce gas, leaving a gooey byproduct known as coal tar.
Coal tar contains chemicals known as polycyclic aromatic hydrocarbons and more volatile compounds referred to as BTEX – benzene, toluene, ethylbenzene and xylene – found in petroleum products.
Illinois Power, the former owner, removed the tar wells and other century-old underground structures leaking coal tar in 1997 and 1998, along with hundreds of tons of contaminated soil and 85,000 gallons of contaminated water. But they weren't able to get to everything.
In its studies, Ameren compared samples with the strictest cleanup standards in the EPA's program, for residential properties, even though it's an industrial-commercial site. If the site is reused as a parking lot, for example, the standards would be lower.
Soil samples that date back to 1990 show widespread contamination on the site itself and a particular area of concern to the north.
Although at least a foot of clean soil was placed over most of the site in 1997-98, and several areas of shallow soil were removed, the top 3 feet of soil remains "significantly impacted," the report said. The shallow groundwater system has also been contaminated over much of the site.
Below 3 feet, the extent of the contamination is fairly well-defined on the south and east sides of the manufacturing site, the report says, but not to the north. That area shows significant contamination, including along a railroad right of way. Some of the deepest contamination is also found there – as far down as 28 feet.
Some samples on the western and eastern edges of the property also showed elevated levels of benzene or other compounds in the soil, but they tended to be minor and relatively shallow, according to the report. The same is true to the south, although two groundwater test wells along the southern edge of the property have shown consistent problems, warranting further investigation, the report said.
Also, a groundwater test well at the northwest corner of Fifth and Hill streets, just outside the Ameren site, tested positive for benzene, a flammable, poisonous liquid that can evaporate into the air quickly.
Some contaminated soil was also found under Hill Street, though it could have come from an old gas main, the report said.
In a fact sheet distributed to residents and others, Ameren says the site "presents no immediate health threat to the public." While the residues contain chemicals that could pose a health risk "in certain circumstances," the risk depends on how – and how long – someone is exposed, it says. And there's been little potential for extended contact with the buried materials at the site – i.e., swallowing or inhaling them, the company says.
While the groundwater is contaminated, consultants point out that most test wells outside the site's boundaries are clean. And, Ameren notes, no one is drinking the groundwater, as the public water supply from Illinois American Water Co. comes from wells a mile or more from the site that draw from the much deeper Mahomet Aquifer.
That doesn't satisfy residents in the area, who want to know how it can be safe to grow vegetables in gardens just north of the property, where soil and water tests have found contaminants within 3 feet of the surface. They also worry about dangerous vapors from the volatile chemicals.
Brian Martin, a consulting environmental scientist for Ameren, said groundwater monitoring wells along Washington Street north of the site tested clean. And even to the south, closer to the site, contamination is too deep to be a concern for gardens on the ground's surface, he said.
Last spring, two homeowners contacted Ameren about that issue, and the utility had consultants taking soil samples that same day, he said.
"We found nothing," he said.
Residents wonder if other properties could have problems even if those two tested clean.
"It sounds like people who don't want to take yes for an answer," Martin responded, adding that he took three soil samples out of each yard. "We've done what's appropriate out there."
According to the EPA, plants don't readily absorb the contaminants in question. So even if the plants drew from contaminated groundwater, the chemicals would evaporate with little impact on the plant, Black said.
Black said there are three possible "pathways of exposure" to contaminants:
– Soil ingestion or contact. People dig or come into contact with contaminated soil, which can cause skin irritation or more serious health problems.
– Groundwater ingestion. Because no one uses water wells and the contaminants haven't infiltrated public water supplies, that's not an issue, officials say.
– Inhalation. Benzene and other volatile chemicals in the coal tar could move from soil or groundwater into homes. Black said the air in a number of homes has been tested and "nothing has been found."
No further air tests are planned unless tests show more soil or water contamination close to homes, he said.
Martin also said Ameren did "extensive" air monitoring to protect the neighborhood during interim cleanup measures in 1997-98 and will do the same once it starts digging up material again.
He said Ameren has tested gardens, play areas and indoor air for homeowners near the site over the years, and never identified any direct exposure. If other homeowners have concerns, Ameren will be happy to talk with them and see if more tests are warranted, he said.
Martin said Ameren has monitored wells on or around the site for 15 years, especially along the site's perimeter, to ensure the contaminants are not expanding, and "most of them are clean."
And some of the soil contaminants in question are "very common in the environment," used in everything from gasoline and street asphalt to moth balls and dandruff shampoo. Some contaminated soil north of the site is very close to railroad ties, another potential source, Martin said.
"I wouldn't characterize them as some sort of outrageous health risk," Martin said. "We've never denied that we have groundwater contamination, and contaminated soils on the property, and in some locations it extends off the property" up to about 150 feet.
"Our key concern has always been the potential exposure."
Pete Sazama, senior project manager for Philips Services, said scientists need to be able to draw a complete picture of where the contamination is, vertically and horizontally, and need further tests to plug the "data gaps."
Ameren is working with the EPA through its voluntary site remediation program to clean up 25 former coal-gas plant sites across Illinois, and the Champaign site is one of the largest in terms of size, Martin said. But Black said the level of contamination there is "very comparable" to the other sites.
"There's a good deal of material that's going to need to be removed. But it's not unusual," he said.
At one site in Cairo, contaminants have moved underneath a levee, making removal difficult without threatening the town's flood protection, he said.
Graduate student Chuck Allen said the Fifth and Hill Neighborhood Rights Campaign plans to have an independent engineer review the Ameren report, which is compiled in three 2 1/2-inch-thick binders filled with technical data.
"It's a monster," Black said.