Pleasant Run Creek meanders through Garfield Park, not far from playgrounds. During the school year, Manual High School students cross it five days a week on a footbridge.
The creek has been long fouled by runoff from Indianapolis' antiquated sewers, and its aquatic life — and residents living nearby — face yet another potential threat. Upstream, Pleasant Run flows through the heart of a closed 87-acre Eastside coke factory.
And it may be picking up toxins along the way.
Within the space of six months, state regulators and an environmental group sent letters to the coke plant's owners questioning whether enough is being done to determine if underground contaminants from the factory — containing toxic chemicals and tarry fluids — are seeping into the stream.
The coke plant's owners, Citizens Energy Group, say the public need not worry. They say tests of Pleasant Run have found no threat to humans. They've also installed pumps and other barriers to keep underground toxic contaminants out of the troubled waterway.
"It works pretty darned well," said Geoffrey Glanders, president and principal hydrogeologist at August Mack Environmental, the firm Citizens hired to assist in its Prospect Street plant cleanup.
MORE COVERAGE: Citizens Energy working to clean up old coke plant site
But environmentalists and state regulators remain concerned. They say the sampling methods Citizens is using may be flawed and that toxins could be flowing downstream and into neighborhoods.
100 years of pollution
Coke is a hardened fuel used in steel mills and foundries. It's formed by baking coal at 1,800 degrees for more than 24 hours. Coke making produces a flammable gas, tar and a host of nasty chemicals, such as ammonia and cyanide.
The plant closed in 2007, but most of the buildings still stand. The eventual demolition and environmental cleanup will be overseen by the Indiana Department of Environmental Management through a voluntary remediation program.
In more than 100 years of making coke and storing material there, some contamination seeped into the ground and creek bed.
Citizens officials acknowledge that inside the plant boundary they've found tarry material below the creek in at least three places. And water samples taken from wells they've dug have a layer of oily fluid on them.
In fact, there was so much of this material underground that Citizens installed a six-well network of pumps in 2012 to siphon up the contaminated water and separate the oil. The treated water is flushed into the sewers.
Citizens officials say the pumps — plus a drain system dug at the factory in the 1980s to trap the gunk underground before it oozed into the creek — are keeping the waterway clear of contaminants.
Meanwhile, Citizens continues to test the rest of the plant to determine the scope of the problem, a massive, complex undertaking at the 87-acre site.
"We're constantly in investigation and data-gathering mode," said Ann McIver, Citizens' director of environmental stewardship.
But is it enough? Two organizations that are sometimes at odds suggest it is not.
Testing wells too shallow?
State environmental regulators and environmental groups have raised concerns about whether toxins continue to leach into the creek, threatening human health and aquatic life.
In December, William Holland, a senior environmental manager at IDEM, sent a letter to Citizens saying that some of the wells the utility had drilled to sample groundwater near the stream had dried out, raising concerns about whether they were deep enough to tap into the portion of the stream that flows below ground.
Holland wrote that "deeper wells are needed to collect representative samples of the groundwater flowing into the stream."
Holland's letter came just five months after Kim Ferraro sent Citizens a letter and a report from a hired consultant. Ferraro is a lawyer with the Hoosier Environmental Council, a frequent critic of IDEM. Ferraro wrote that the "proposed biological assessment of Pleasant Run Creek is deficient in scope."
Citizens officials insist that the dozens of samples across the site, as well as inside the creek, yielded accurate results, and they plan even more tests.
They say that the wells Holland cited were plenty deep enough to sample the bottom of the stream. Glanders, Citizens' consultant, said IDEM didn't realize the coke plant actually sat on an aquifer that contained more clay than elsewhere in the city.
Glanders says the clay reduces the amount of underground spillover from the creek, making the wells more likely to dry out.
Bruce Palin, IDEM's assistant commissioner in the Office of Land Quality, said Glanders' theory is plausible, but Citizens still hasn't provided his agency with enough survey data to map out the underground geology.
'IDEM remains concerned'
Dick Van Frank, a board member of the Indianapolis group Improving Kids Environment, said he remains skeptical of Citizens' insistence that the creek is safe.
He points to a document IDEM officials wrote in February in which they reported a number of problems. Sediment samples below the creek, for instance, were held in broken jars, raising questions about whether the samples could have been compromised.
"IDEM remains concerned with the creek sediment sampling results to date," IDEM officials wrote in a meeting summary. "Incomplete sampling methods and results make it very difficult to compare and evaluate data."
Van Frank, a former state air quality board member who has voiced concerns for years about pollution from the coke plant, says those who live in the area "deserve better than that" from the plant's owners.
But Citizens officials say they're working as fast and efficiently as they can to gather accurate data, and at a substantial cost.
McIver, Citizens' director of environmental stewardship, said her organization has spent $1.5 million this year alone on the coke plant. She said similar amounts or more have been spent each year since the plant closed.
She said her team is doing everything it can to protect human health and the environment while developing a cleanup plan.
McIver said the hope is the defunct coke factory might be sold and redeveloped into a new industrial site. IDEM records show that there's a possibility the area also could be developed for recreational use.
In the meantime, McIver said, Pleasant Run is a top priority.
"Citizens has all along said that our intention is to protect Pleasant Run Creek," she said. "It's an important community asset."
Call Star reporter Ryan Sabalow at (317) 444-6179. Follow him on Twitter: @RyanSabalow.