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December 10, 2015


Department of Environmental Protection to Increase Air Monitoring in Riverbank State Park and the Nearby West Harlem Neighborhood

City and State Health Departments Confirm no Immediate Health Risk to Community

City has Committed to Cleanest Air of any Large U.S. City by 2030

The North River Wastewater Treatment Plant is located on the Hudson River and adjacent to the West Harlem neighborhood. The plant cleans and treats the wastewater produced by nearly 600,000 residents living in the western portion of Manhattan. Prior to the plant’s activation in 1987, raw sewage was regularly discharged into the Hudson River causing significant environmental damage.

The City has committed to achieving the best air quality of any large U.S. city by 2030.

As required by the New York State Department of Environmental Conservation (DEC), for the past several weeks DEP has been collecting samples of the air at Riverbank State Park, which sits atop the plant. Some of the samples taken near the plant’s exhaust stacks at the northeast end of the park have recorded formaldehyde at levels that, while significantly below the Federal Occupational, Safety and Health Administration’s (OSHA) standard, occasionally exceeded the guidance criteria established by DEC for air contaminants. DEC’s guidance level is 30 micrograms per cubic meter, while the sampling results have averaged 32 micrograms per cubic meter. California’s limit is 55 micrograms per cubic meter while OSHA’s standard is 800 micrograms per cubic meter.

The New York City and New York State Departments of Health have determined that the recorded levels pose no immediate health risk to park visitors or the West Harlem community. Though formaldehyde is associated with cancer, a person would need to continually be exposed to significantly elevated levels of formaldehyde, both at work and at home, over an entire lifetime in order for them to increase the chance of developing cancer. Still, DEP is taking immediate steps out of an abundance of caution. 

Formaldehyde can be created by the incomplete combustion of the methane gas that is produced during the wastewater treatment process. In the near-term, DEP is evaluating modifications to plant operations in an effort to reduce the concentration of formaldehyde and, in coordination with DEC, will expand the collection of air samples both within the park and into the nearby West Harlem neighborhood in order to further assess air quality. Previous studies of air quality in areas close to the North River plant found that formaldehyde levels were comparable or lower than those in neighborhoods throughout New York City. Residents may notice the installation of new air monitoring devices. In addition, DEP has already begun the design and allocated funding for a $230 million plan to replace all the engines that power the plant with a highly efficient and clean burning co-generation system.                     

DEP manages New York City’s water supply, providing more than one billion gallons of water each day to more than nine million residents, including eight million in New York City. The water is delivered from a watershed that extends more than 125 miles from the city, comprising 19 reservoirs and three controlled lakes. Approximately 7,000 miles of water mains, tunnels and aqueducts bring water to homes and businesses throughout the five boroughs, and 7,500 miles of sewer lines and 96 pump stations take wastewater to 14 in-city treatment plants. For more information, visit, like us on Facebook, or follow us on Twitter.

More Information

NYC Department of Environmental Protection
Public Affairs

59-17 Junction Boulevard
19th Floor
Flushing, NY 11373

(718) 595-6600