If you're a New Yorker, perhaps you've seen one or both of the above official-seeming posters during your commute (I've seen the one on the left).
Not to worry, ANIMAL NY reached an MTA spokesperson: They're "the work of pranksters," and not via the Metropolitan Transit Authority or any government agency.
But, as ANIMAL noted last month, the invisible gas test is very real: The NYPD will be filling the city with invisible gases (called perfluorocarbons) this summer to attempt to test how harmful airborne substances would spread in the event of a chemical attack. However, the tests won't be happening "weekdays" "JUL 1-30" as noted on the fake poster.
Once you read the copy on the second poster (right) — which refers to the nuclear power plant at Indian Point Energy Center — you quickly realize it's inauthentic. But, not entirely inaccurate.
GREYWATER (Note the hastag and MTA-looking logo on the posters) is a nickname for perfluorocarbons.