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Massive Trichloroethylene Contamination in Brooklyn's Gowanus Canal Area Illustrates How New Yorkers Are Unknowingly Exposed to Environmental Health Hazards

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New York's legacy of TCE hazards is starkly illustrated by the infamous Gowanus Canal in Brooklyn, NY. Over the last century, hundreds of industrial, utility and manufacturing sites released TCE and "black mayonnaise" coal tar into the canal. The U. S. Environmental Protection Agency (EPA) is currently removing nearly 600,000 cubic yards of contamination at a cost of $1.5 billion.

TCE sites in this area threaten public health with toxic Soil Vapor Intrusion (SVI) hazards that pollutes homes, businesses and other structures.

Hundreds of thousands of residents have been exposed to TCE and other toxic pollutants for decades due to government's failure to safeguard public health. To make matters worse, massive proposed redevelopment of the area will result in even larger numbers of people living on or near TCE sites.

The unfolding toxic health crisis in the beleaguered Gowanus Canal Area is a harbinger of TCE hazards in every major community in New York.

TCE Indoor Air Contamination Hazards Came to Light Beginning in March, 2023

In March 2023, Toxics Targeting revealed that a popular club located at 514 Union Street about a block away from the Gowanus Canal failed to alert the public that TCE was detected two years earlier at more than 20-fold the indoor air protection guideline of two micrograms/m3 and more than twice the "immediate action level" of 20 micrograms/m3.

Despite extraordinarily high levels of Trichloroethylene and other toxic contaminants documented on, under and around the site in soil, soil vapor and groundwater, the New York State Department of Environmental Conservation (DEC) did not propose to require the site to be restored to “pre-disposal conditions, to the extent feasible" as required by law.

Instead, DEC proposed to allow, "In-situ ("in-place") application of remediation products via injections at varying targeted doses designed to capture and enhance biodegradation of chlorinated volatile organic compounds (CVOCs);"

See: December 2022 Brownfield Cleanup Program C224318 Fact Sheet - 514 Union St, Brooklyn

This proposed Interim Remedial Measure plan is totally inadequate because it would not clean up the toxic contamination at the site in strict compliance with all applicable regulatory requirements. Nevertheless, DEC stated, “This Interim Remedial Measure (IRM) is likely to represent a significant part of the cleanup of the site.”

Toxics Targeting submitted detailed comments requesting that the proposed IRM plan be rejected in favor of a comprehensive site remediation in strict compliance with all applicable regulatory requirements.

See: Please Do Not Adopt the Fatally Flawed Proposed "expedited cleanup of contamination at 514 Union Street," Brownfield Site # C224318

The 514 Union Street site is located in an area of the Gowanus Canal undergoing massive redevelopment. 514 Union Street is part of another toxic polluted property at 473 President Street proposed for redevelopment. Largely unbeknownst to the public an "off-site area" of 473 President was being investigated for Trichloroethylene and other toxic Soil Vapor Intrusion contamination hazards.

Shockingly High TCE Indoor Air Contamination Documented

In June 2023, extraordinarily high TCE levels up to 900 micrograms/m3 were reported in a building believed to be 543 Union Street. Even though the building was not identified due to privacy concerns, it can be confirmed by the text of the report as well as other available information.

See: Why 543 Union Street is Almost Certainly Property Number 2 Documented With 900 micrograms/m3 of Trichloroethene/Trichloroethylene on 2/15/23 - 2/16/23

This building is located half a block NW from 514 Union Street and was monitored circa 2/23 for TCE as part of the 473 President Street Off-Site investigation. TCE exceeded the indoor air protection guideline by 450-fold and the "immediate action level" by 45-fold.

These TCE problems were never publicized and reportedly persisted through the spring of 2024. TCE and other toxic indoor air contaminants were detected in at least five additional buildings that require air pollution mitigation to safeguard public health.

Gowanus Community Update 4/2023 excerpts and full update

New York State Department of Health Air Sampling Results Letter (and attachments) - 282 Nevins Street, Brooklyn - April 7, 2023

473 President St Brooklyn Site: Figure 5 Off-Site Soil Vapor VOC Detections

473 President St Brooklyn Site: Figure 4 Off-Site Groundwater VOC Detections

Unprecedented Soil Vapor Intrusion (SVI) Investigation Launched in Entire Gowanus Canal Area Circa September, 2023

In September 2023, shockingly high TCE indoor air contamination monitored in 543 Union Street and nearby sites evidently prompted the State Department of Environmental Conservation to launch an unprecedented SVI investigation of the entire Gowanus Canal area. The first phase of the SVI investigation focused on 632 buildings at the canal's northern end. Through early February 2024, a total of 96 property owners had authorized access for monitoring, but only 49 structures had been analyzed.

The SVI Investigation has two fatal flaws. First, at the current pace, the SVI Investigation would take many years to complete because indoor air testing is only conducted during the heating season between November and April. Second, uncooperative property owners will prevent the full-scope of SVI hazards from ever being comprehensively assessed.

These shortcomings are obviously unacceptable. That is why requiring Potential Responsible Parties to conduct mandatory testing of all properties within 1,000 feet of their Brownfields and other Toxic sites is likely the only way the SVI Investigation can be completed comprehensively and in timely fashion.

Trichloroethylene Reportedly Documented in Soil Gas Vapor, Indoor Air, Ambient Air, Soil and Groundwater in the Northern Gowanus Canal Area

Gowanus Canal Area - September 2023 Community Update

Despite the meager progress being achieved to investigate SVI hazards in the Gowanus Canal Area, Governor Hochul announced a proposal on February 9, 2024 to develop 18 major housing projects on or near Brownfields and other toxic sites in the SVI Investigation Area. At least eight of these sites involve Brownfields that are currently included in the SVI Investigation.


On May 30, 2024, DEC declared that 514 Union Street "poses a significant threat to public health or the environment." In a landmark decision, a "completed cleanup" of "contamination" is required to "make the site fully protective of public health and the environment."

See: How DEC's Shockingly Inadequate 12/22 Interim Remedial Action Proposal for 514 Union Street Was Rejected in Order to Require a Comprehensive Toxic Site Cleanup to Halt a "Significant Threat to Public Health or the Environment."

DEC’s stunning public health and environmental threat declaration and rejection of its original stunningly inadequate IRM proposal fulfills Toxics Targeting's request.

DEC precedent setting decision could very likely result in strict enforcement of the State legal mandate to require Brownfields and other toxic sites to be restored to “pre-disposal conditions, to the extent feasible” throughout the Gowanus Canal Area and all over New York.

Click Map to Expand

Draft: Overall Area Potentially Impacted By Toxic Pollution Reportedly Migrating From the Public Place Coal-Tar Contaminated Site: 224012,C224012,C224012B in PDF format

Gowanus Canal Area NYS DEC Remediation Sites in PDF format