The airflow in New York City subways is being studied by NYPD and the US Government. On Tuesday, NYPD and Brookhaven National Lab conducted a study of the airflow in the subway system. Two other surveys are scheduled later in the month.
A gas was released in Manhattan into the tunnels. Monitors were constructed around the boroughs. The gas has been described as a harmless and odorless.
NYPD Police Commissioner Ray Kelly says terrorists have targeted transportation systems and all efforts are being made to protect the system. He described the tracer gas as something that is used in medical procedures.
Cathryn Swan from the No Spray Coalition expressed concern about oversight of the program. Government agencies have called for more studies of exposure to perfluorocarbons.