Thank you for riding the MTA.

At this time we would like to thank you for participating in a joint study conducted by the NYPD and Brookhaven National Laboratory, sponsored by the Department of Defense.

During the month of July riders will be randomly exposed to Perfluorocarbon gas in 5 boroughs and on 21 subway lines in an effort to study airflow throughout the MTA subway system.

Perfluorocarbons are colorless, odorless, and powerful man-made greenhouse gases that contribute to global warming. They are emitted as a by-product during aluminum production, are used as solvents in the electronics industry, and as refrigerants in many cooling systems.

We still do not fully understand the health effects of Perfluorocarbon gas exposure, though exposure to Perfluorocarbons are linked to the early onset of menopause. Studies in animals have found these gases significantly alter liver and thyroid function, increase the risk for tumors, and cause failure in reproductive organs.

These gases are being dispersed as a test for your protection against an unwanted chemical attack.

Thank you for riding with the MTA and have a safe day.