Men in orange vests released a harmless, invisible, odorless gas on a subway platform at Grand Central terminal on Monday, part of a test of how air moves through tunnels and potentially how a biological contaminant would travel through the nation’s biggest transit system during a terrorist attack.
There is no health risk. The gas contains tracing particles that look like drops of perfume from an atomizer before quickly dissipating.
Detectors have been installed in more than 55 stations and some outdoor spots to see where the vapors go. The collection boxes pull air through filters and capture particles into bags for analysis. About 12,000 samples will be taken this week, federal officials said.
Things to come?