If gas, smoke or some other contaminant is released into the New York City subway, where does it go? That's the question that scientists from Brookhaven National Laboratory on Long Island and city agencies are trying to answer with a series of tests this month aimed at beefing up the city's preparedness for potential terrorist attacks or accidental leaks.

 

The Subway-Surface Air Flow Exchange (S-SAFE) project will take place over three nonconsecutive days in July, including today (July 9), and will involve releasing a class of "non-toxic, inert, odorless and invisible" gases called perfluorocarbons into select subway stations and street-level locations for 30 minutes, according to a Brookhaven release. These tracer gases will be monitored by about 200 sampling devices placed strategically to track where the gases flow.