BANGOR, Maine — While the city is dredging up coal tar deposited along the waterfront years ago — a process that is scheduled to take just over two weeks — it is going to be smelly, city officials and consultants said on Wednesday.
“The project will undoubtedly create some odors,” said City Engineer Jim Ring, who has worked for more than a dozen years with Wisconsin consultant firm RMT Inc. and state and federal regulatory agencies to address mitigating the hazardous materials that line the Penobscot River’s shoreline.
The work is expected to begin within a week, he said.
The foul smell will be detectable in the general area of the waterfront and could reach into the city a couple of blocks, said Eugene McLinn, RMT consultant and geologist who has worked on Bangor’s project for 11 years.
“We’re going to move aggressively to get the coal tar out in 15 days,” he said. “After that phase is completed, we’ll construct the cap” to seal the unreachable tar along the edge of the river and also seal off the smell.
Coal tar is a known carcinogen and was deposited along the Penobscot River’s bed by Bangor Gas Works, which operated from 1881 to 1963 on land where Shaw’s now sits. The dark substance, which has somewhat hardened on the riverbed over the years, is a byproduct of gas manufacturing and was deposited in the river through an old stone sewer that connected to the Main Street gas plant.
There are several steps in play to keep the smell as minimal as possible while dredging is happening, and there will be three air monitors set up that will test air quality every 15 minutes, McLinn said. One monitor will be placed on the Brewer side of the river and two will be near the 1.3-acre cleanup site.
“There is going to be a number of levels of containment,” which will prevent the tar from reaching the water’s surface and releasing its pungent smell into the air, McLinn said.
The odors are not dangerous to people, even those with health issues such as asthma, said Kathy Howatt, Maine Department of Environmental Protection project manager.
A huge crane is visible at the site where the work will be done. Work crews are constructing a containment curtain that will “confine the work area to keep the [contaminated] sediments in the containment area and the fish out of the containment area,” Howatt said.
Between 6,000 and 7,000 cubic yards of tainted sediment will be removed from the river, taken to a “negative-atmosphere” warehouse located just down river from the site for “de-watering,” and then will be trucked to the Juniper Ridge landfill in Old Town, Ring said.
The cost of the massive cleanup project is expected to run about $7 million, which will be paid using settlement funds from Citizens Communications Co., a group of third parties a federal judge ruled was responsible for a majority of the cleanup. Bangor tax increment financing district funds will cover any additional costs.
“It’s a big project, an expensive project and a necessary project,” Bangor Mayor Gerry Palmer said.
For most of the year, the coal tar deposit is not much of a problem. But when the water warms in August, the deposits rise to the surface in small blobs that stick to objects such as boats and animals. Coal tar, when absorbed through the skin, is known to cause cancer.
McLinn, along with RMT consultant John Rice, designed the sloped stone cap that will eventually seal off the contaminated area. He said the cap’s design is very unique because it allows methane and other gases to escape, while trapping the toxic tar.
The cap will be constructed of a layer of clay and an impermeable layer that allows gases through but not the remaining tar droplets. Those gases will be vented along the waterfront, and the top of the cap will be created with stones that will resemble a regular Maine shoreline, McLinn said.
Ring and Palmer both said it’s great to see the cleanup actually begin after working on the project for more than a decade. They both also said the cleanup would do wonders for the waterfront, which Palmer described as one of the city’s biggest asset.
“Forty years ago you wouldn’t even wash your dog in this water,” he said. “It was a mess down here. We’ve come a long way. We’re still working to make this area better.
“I’m very excited about this project,” Palmer said later. “This is going to be a terrific improvement.”