This is a test. This is only a test. Keep calm and carry on. From CB6 (emphasis added):
Please be advised of the following notice from the Office of Emergency Management...
Notification issued 9/12/13 at 5:00 PM. From 8 PM Friday, 9/13/13 until 2 AM Saturday, 9/14/13, the FDNY and US Marine Corps are conducting an exercise at the Barclays Center, at Atlantic Ave and Flatbush Ave, Brooklyn. Expect to see military vehicles and personnel in hazardous materials suits near Dean Street, between Flatbush and 6th Aves, as well as volunteers in disaster simulation makeup. This is only a drill.
Best, Craig Hammerman