NEW YORK (AP) – Homeland security officials will release an invisible, harmless gas into part of New York City’s subway system as part of a test of how air moves through the tunnels and platforms.
They say the data would be useful in understanding how toxic vapors or biological contaminants might move through the tunnels during a terrorist attack.
Officials say the test begins at 11 a.m. Monday and will last for five-days.
The gas released into the system will contain tracing particles. Detectors have been installed in several stations to see where the vapors go.
There is no health risk to the public.