The once-industrial oasis of Gowanus is notorious for its contaminated canal, pollutants of which include E.coli, mercury, lead, and forms of bacteria that some scientists say were previously unknown to man. What is less known is that some contaminants near the canal are under the ground. That includes a bed of carcinogenic coal tar right under the popular Douglas and Degraw Pool, known by the community as the “Double-D,” where 28,000 people went to beat the summer heat this year.
Both the Environmental Protection Agency and the State Department of Environmental Conservation believe there is no cause for concern—at least not for swimmers. The water in the pool and the soil nearby it have been extensively tested, according to the DEC, and found to be safe. The City does plan to excavate the coal tar underneath Double- D eventually—not because of the danger to swimmers but because of its potential to flow downstream into the Gowanus.
But that will likely take a while. Questions of eminent domain and limited space have held up efforts to locate a substitute pool, so the excavation operations are on hold, and the city does not seem to be in a hurry.
Some experts wonder if it should be, however. There is some question as to how long the layer of cement separating the swimmers from the toxic pollutants underneath will remain effective.
In the 1970s, the city built about 20 public pools around the boroughs, among them the Double-D. Forty years later, it remains a neighborhood institution, serving low-income residents from the three NYCHA developments nearby, as well as residents of Carroll Gardens and Boerum Hill, Gowanus’ neighbors to the south and north. The Double-D is one of just 15 public pools in all of Brooklyn, and one of only five public spaces offering a smaller wading pool for younger children.
Coal tar’s link to cancer was first documented in the 18h Century, when an English surgeon known as the father of the study of environmental carcinogens, Sir Percivall Pott, noticed high incidences of cancer among chimney sweeps. Think Mary Poppins. Except instead of grown men dancing gaily from rooftops, young, working-class boys armed with brooms who squeezed their way up chimneys, often naked so not to ruin their clothes. Sir Pott began seeing notable incidences of scrotal cancer among the chimney sweeps. He determined that the direct gonadal interaction with the soot was the cause. And by the turn of the century, Sir Pott was seeing arm cancer as well.
Coal tar is not just dangerous to those who touch it. A 2011 Report on Carcinogens from the U.S. Department of Health found that mice and rats that inhaled coal tar fumes presented skin tumors. According to Dr. Allen Hatheway, a geological engineer and author of the book “Remediation of Former Manufactured Gas Plants & Other Coal-Tar Sites,” the substance could be problematic if “you eat it, breathe it, or you get it rubbed in through your skin.”
So how did a bed of coal tar get underneath one of the most beloved pools in Brooklyn? And what is it, anyway?
In the 1870s, on the heels of the Industrial Revolution,a burgeoning industry blossomed the banks of the newly-constructed Gowanus Canal. Three Manufactured Gas Plants (MGPs) were among the largely unregulated industries there. One of them was Fulton Municipal Manufactured Gas Plant (a predecessor to present day National Grid), a company that produced gas products for basic utilities: lighting, heating, and other functions that utilities companies still cover today. The gas plants began to produce byproducts, including concoctions of Polycyclic aromatic hydrocarbons, or PAHs, and other residuals. This mixture is known colloquially as “coal tar.” Or, as Dr. Hatheway puts it in an interview, “a witch’s brew of toxic chemical compounds.”
From the 1870s almost until 1930, a portion of Fulton’s operations took place on the current site of the Thomas Greene Park Playground, home to the Douglass and Degraw Pool.
Fast-forward to 2010, when the Gowanus Canal became an EPA Superfund site and research uncovered a bed of decades-old coal tar underneath the pool, where Fulton used to keep its equipment. The toxic bed is concentrated throughout the entire length of the 75-foot pool. And it goes down deep. So deep, in fact, that Walter Mugdan, an EPA Regional Director of the Emergency and Remedial Response Division calls it “sort of the motherload of the coal tar.”
Gowanus residents may not need to retreat to dryer ground. Hatheway says that it is unlikely that casual swimmers will see any serious health problems. The people for whom he does raise concern are what he calls the “chronic” visitors—“In other words, these are guys that go to the pool every day.”
Nate and Dash Cosaboom-Son, nine year-old twin boys who live just a few blocks away from Double-D at Dean St. and Nevins St., are among the population of regular visitors. In fact, during the summer months, the boys go almost every day. “We’re there pretty much right after they open and right when they close,” says their mother, Diana Son. “They run around all day and get really sweaty and hot and…they go there to cool off.”
The EPA says that kids like the Cosaboom-Sons have no reason to fear. Mugdan says that the pool’s “hard concrete surface acts as a cap…a physical barrier.” The only reason the city plans to excavate the pool is the possibility that the coal tar could actually be leaching downhill into the nearby Gowanus Canal, says Mugdan. As for the pool, the EPA says there is “…no indication whatsoever that they’ve been exposed.”
Hatheway is less sanguine. According to the engineer, coal tar could rise up through fractures or cracks in the concrete. “None of this has any power or way except to work its way through porous medium,” he says, adding “Concrete is loaded with fractures.”
Joe McHugh, of McHugh Forensic Consultants, is a professional engineer with more than forty years experience in paving and construction. According to McHugh, if concrete is “…properly batched together and it’s properly placed—and most importantly it’s properly cured—you can pretty much eliminate all that cracking.” In fact, McHugh notes that most cracks are evident to the naked eye.
New York City engages in routine maintenance to fix cracks in the pool. Before each season, “NYC Parks conducts regular maintenance, including painting and cleaning work on all outdoor pools,” says Commissioner Mitchell J. Silver’s office. As for damages sustained throughout the season, NYC Parks handles those as needed. They also test for PH and chlorine levels each hour, if not more frequently.
In spite of such efforts, it appears that there may still be cracks—at least one on the Douglas side of the pool that appears as though it was possibly repaired, and another on the Nevins side.
Hatheway believes that dark smudging along concrete seams “should be cause for concern.” It could represent “some form of linear upward-discharge of coal-tar light oil.” The discharge, says Hatheway, might cause swimmers to come into direct dermal contact with coal tar.
But there is also a potential for cracks beneath the surface, often caused by environmental circumstances that might not be visible to the eye. Tree roots, for example, can form “conduits” underground, which can get “bigger and bigger and bigger and that’s when you can get potential failures,” says McHugh.
Natural disasters like earthquakes and floods, such as those seen during Superstorm Sandy, could also lead to cracking, along with other weather events like freezing temperatures. According to McHugh, water can get into small cracks and during a freeze, expanding the crack from within. Both Hatheway and Paul Duby, a professor of Environmental Sciences at Columbia University, echoed this possibility. It would just take one freeze to do the trick. (New Yorkers may remember an unseasonably warm Thanksgiving last year; early 2016 brought freezing temperatures into March, including those seen at the end of January during Winter Storm Juno).
But as for coal tar seeping through the cracks, Duby believes it would need a push. Like McHugh, Duby suggests that underground vibrations caused by forces like construction could do the trick. In the up-and-coming nearby neighborhood of Gowanus, construction is rampant.
Hatheway feels there is yet another way for coal to enter the pool, aside from cracks and vibrations: Through drains. And a black, rectangular material that surrounds both the main pool’s and wading pool’s drains, could, according to Hatheway, “… mask evidence of the inward passage of PAH compounds.” The tar substance could also come up through shower drains on the pool’s property. Coal tar even breach the concrete barrier in the form of vapor, he says. If the light oils found in coal tar evaporate and “…moves into a gaseous form…it could move through the concrete.” In other words, there is a potential for coal tar to come up through bubbles.
The EPA has not conducted studies to assess the potential for coal tar penetration via bubbles or shower rains, says Rodrigues. He did say, “More importantly, if the EPA were aware of an imminent risk to human health, we would take measures to address them.” The New York State Department of Environmental Conservation, the entity that manages the upland sites along the Canal, doubled-down on the government’s position that coal tar could not seep into the pool. There have been “misleading reports…circulating for several years and have been discredited,” says Rodney Rivera, a special assistant at the DEC.
While the City does intend to excavate the ground under the pool, the question of when is not so simple. Before the cleanup can begin, the City and National Grid must find a replacement location for the pool in an area where space is a hot commodity. Before work on Double-D can begin, “we would actually have to not only find a location…it would have to be constructed…so not to be an interruption for services to the community,” says Natalie Loney, a Community Involvement Coordinator for the EPA.
A separate contamination issue in the area further complicates the pool’s cleanup. The City is responsible for installing sewage retention tanks in Gowanus, because rain-induced sewage overflows cause sewage to leak into the Canal, further polluting it. Because space is so limited in the blossoming neighborhood, the EPA proposes that these tanks be placed underneath the Double-D Pool, when the soil there is excavated. If community activists who oppose that plan prevail, the pool’s cleanup could be delayed further. So next summer, Double-D Pool will presumably be open for business.