Environmental Assessment of Proposed Tracer Particle and Gas Releases: Chemical and Bio-Defense Testbed (CBT) Program, Urban Threat Dispersion (UTD) Program, Version 5 [open pdf - 9MB]
From the Executive Summary: "The United States (U.S.) Department of Homeland Security (DHS) Science and Technology Directorate (S&T), in partnership with the Metropolitan Transportation Authority (MTA) and other stakeholders in New York City (NYC), is proposing to conduct testing events to improve resiliency of urban areas and transportation systems against chemical or biological terrorist attacks (Proposed Action). This Environmental Assessment (EA) documents the analysis of any potential effects on the environment resulting from the Proposed Action. This EA is being coordinated with stakeholders and the public for information and comment, in accordance with the National Environmental Policy Act (NEPA) of 1969 as outlined in 40 CFR [Code of Federal Regulations] Parts 1500-1508 and DHS Directive 023-01, Rev. 01 and DHS Instruction Manual 023-01-001-01, Rev.01, implementing NEPA. [...] The Proposed Action would take place between September 2021 and May 2022 and involves the release of particle and gas tracer materials directed into the open-air space in several predetermined locations within NYC. The Proposed Action would include the release of low concentrations of safe particle and gas tracer materials as part of two programs - the Urban Threat Dispersion (UTD) program and the Chemical and Bio-defense Testbed (CBT) program. The Proposed Action and the No Action Alternatives are considered in this EA."
Department of Homeland Security: https://www.dhs.gov/