EPA Looks into Simulate Chemical Attack to Boost Risk Assessments

EPA sources say an ongoing simulated gaseous release in New York will help emergency workers respond to a chemical attack or a major accidental spill in densely populated areas, and could improve EPA's ability to assess public health risks from such releases.

The federally funded simulation is being conducted through this week as part of a New York City research initiative, which will generate unprecedented data for EPA, the Department of Homeland Security (DHS), the National Oceanic and Atmospheric Administration and the departments of Energy and Defense to track both the movement of a gas release as well as human reaction to such an event.

A key EPA source argues this effort will help emergency responders -- such as fire officials, police officers, medical professionals and EPA staff -- better understand what areas to target and what assistance to provide potential victims of exposure to toxic gases such as chlorine or vinyl chloride.

The project is part of an Energy Department initiative that began more than five years ago to study how air flows in different urban environments. Officials from a number of government agencies, including EPA, have conducted similar tests in Salt Lake City in 2000 and Oklahoma City in 2003.

The results of the New York study could have broad implications for EPA policies. One EPA source says once the program is complete, the results could be shared with agency officials in charge of the Superfund regulatory blueprint, known as the National Contingency Plan (NCP). Additionally, the source says the agency may conduct similar tests for air particulate matter and metals, which could include releases of dioxins, polycyclic aromatic hydrocarbons (PAHs) and cadmium.

In the event of a hazardous chemical release, EPA follows procedures outlined in the NCP and a revised National Response Plan, which was issued last January by DHS. As part of the NCP, EPA chairs a team of 16 federal agencies that respond to hazardous material releases and coordinate with a DHS-managed interagency group to assemble a support team, which may investigate and contain airborne pollutants, oil spills and radioactive materials, as well as monitor the impacts of an attack on the nation's agriculture and natural resources.

The New York effort, which began Aug. 6 and will continue through Aug. 26, is simulating a chemical accident or attack by releasing the colorless, odorless, non-toxic and non-combustible gases perfluorocarbon and sulfur hexafluoride in midtown Manhattan.

Tracers placed throughout the area on light poles, buildings, in subways and other stationary objects will monitor the wind, temperatures and other key meteorological variables. The tracers will fill sample tubes or bags with air at pre-determined times. As many as 20 EPA staff and other simulation participants will also wear personal tracers -- which are about the size of a pen -- and will be asked to react to an unspecified release, which may assist researchers in understanding human responses to a chemical attack or accident.

The study will investigate four areas of airborne transport of a light gas, including movement through streets and around the tall buildings in midtown Manhattan, infiltration into an office building, movement through the subways and personal exposure. EPA, DHS and other agencies conducted a similar study in New York last March to test releases during the winter, and will conduct another test next spring to study the results during that season. EPA and DHS sources say the results will give the government agencies a better idea of the seasonal effects of a gas release, both on humans and the environment.

The New York effort, which is part of the city's Urban Dispersion Program, follows the earlier field studies in Salt Lake City and Oklahoma City that included simulated accidental gas releases, but one EPA source says the ability to track human behavior in the New York study will further help emergency responders in developing a reaction strategy for chemical releases. Since the September 2001 terrorist attacks on New York, a number of environmental groups and congressional lawmakers have raised concerns with chemical security vulnerabilities in New York City and at chlorine plants in nearby New Jersey.

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