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NYPD Plans to Release Non-Toxic Gases in the Subway

The NYPD will release and track harmless gases in NYC's subway to better prepare for accidents and terrorist attacks
Morning commuters crowding into a New York subway car
Morning commuters crowding into a New York subway carPhotograph by Robert Nickelsberg/Getty Images

In an effort to prepare against chemical, biological and radiological attacks in the New York subway, the New York Police Department has announced plans to release harmless gases into the city’s streets and subway stations to better understand the pathways of airborne contaminants. Officials will use more than 200 sensors, set up throughout all five boroughs, to track these benign gases as they disperse. They’ll then use that data to build a computerized model that can help predict how airborne contaminants might behave, depending on locational and weather conditions.

“If some sort of poison or contaminant were dispersed in the atmosphere of New York City, either accidentally or through a terrorist attack … we’d have an idea how it would travel,” says Paul Browne, deputy commissioner of the NYPD. “That would help guide us as to what our responders should do and what instructions we should give the public—for example, do you shelter in place or do you evacuate—and if so, in which direction.”