The NYPD’s Subway Gas Experiment Begins Monday

NEW YORK, NY - AUGUST 29: Commuters wait for the subway August 29, 2011 in New York City. One day after Hurricane Irene hit New York the mass transit system, including subways and buses, began moving again in a limited capacity in time for Monday's rush hour. (Photo by Joe Raedle/Getty Images) Photo: Joe Raedle/2011 Getty Images

Remember that practice subway gas attack the NYPD was planning for this month? Well, the first day of that is tomorrow, when they'll pump an odorless, colorless, nonreactive gas into the tunnels to see how the air flows down there, and what a chemical leak or gas attack might look like. From the way the city is describing this, riders won't even be able to tell they're doing it; but if someone does start freaking out, remember that this is just a test.