Gowanus Canal CAG seeks answers from DEC after more chemical fumes are found in PS 372

Soil vapor is still leaking into the annex of PS 372 in Gowanus, according to a letter to parents and staff from the New York State Department of Environmental Conservation (DEC) and the Department of Health (DOH) sent out over the Juneteenth holiday weekend. 

Now, the Gowanus Canal Community Advisory group is seeking answers from the state agency about the effectiveness of the previously installed sub-slab depressurization (SSD) system and future mitigation. 

In a draft of a letter to DEC officials, the CAG writes, “The central issue is therefore straightforward: the existing system may be performing as designed, but the persistent cellar indoor-air pattern has not been fully explained and the additional mitigation has not yet been completed and verified. Before normal school-year operations resume, the CAG seeks clear answers and documented protections in five areas.” Specifically, the CAG wants the state to 1) explain the continuing detections; 2) complete and verify the additional mitigation; 3) use a monitoring plan that accounts for variability; 4) provide a health and occupancy determination; and 5) establish accountability and public communication. 

In 2023, the DEC initiated a soil vapor intrusion (SVI) study in Gowanus, prompted by the findings of high levels of toxic fumes inside the Royal Palms Shuffleboard Club (which now has a sub-slab depressurization system of its own, making the air safe to breathe). PS 372 was found to have harmful levels of petroleum-based vapors inside its annex, and the SSD—a fan that essentially creates a vacuum under the foundation, forcing upward-traveling air in the soil into a pipe instead of through cracks in the concrete—was installed in the cellar in March 2025. 

The system was modified in June 2025 to “add an additional suction point to improve sub-slab vacuum in the western portion of the Annex building and by sealing additional identified potential soil vapor intrusion pathways, including cracks and floor seams located in the boiler and pump rooms using water- and vapor-proof sealant,” an agency spokesperson told the Star-Revue in a statement.

At the July 28 general CAG meeting, the letter was discussed. Both parents and CAG members were allowed to ask questions, but DEC officials did not immediately respond, instead promising to take the questions back and to respond at a later date.   

“The parents just want to be reassured that our kids are in a safe environment, and at the moment, I think most of our parents of our youngest kids who are in that annex building are not sure if their kids are safe or not,” Julia Finegan, a parent of a student at the school, told the CAG. 

According to the DEC’s June letter sent to parents and staff, initially reported by Gothamist, the source is currently unknown but is believed to be above ground. Air samples taken during the summer of 2025 revealed that volatile organic compound concentrations had remained similar to before the depressurization system was installed, prompting further investigation. 

The current levels of vapors are not harmful, the DEC says, and the school year can begin as normal in September, Gothamist reports. 

“Indoor air sampling results for the PS 372 Annex building have shown in the past that certain chemicals were detected above typical background range but still less than what would constitute an increased health risk. Since then, optimization of the school’s sub-slab depressurization system and HVAC system has been undertaken to ensure that the health of students and staff are further protected prior to the start of the new school year,” the spokesperson wrote to the Star-Revue.

Lenny Siegel, the executive director of the Center for Public Environmental Oversight told Gothamist, “It looks to me like the DEC’s doing what any standard response would be. I would say they’re doing a good job.”

The DEC is working on a plan to mitigate the remaining vapors. The DEC spokesperson wrote, “DEC, in conjunction with DOH, and the New York City Department of Education are coordinating measures to optimize and supplement the existing HVAC with a Heat Recovery Ventilator (HRV) system and continue to operate the existing sub-slab depressurization system.”

A virtual town hall will be held on Monday, Aug. 24, at 6:30 p.m., to discuss the issue. You can sign up here.