Hmmmm. A search of "propylene glycol" and "new york" revealed this site.
http://www.nyc.gov/html/dep/html/press/99-01pr.html
In 1999 it was reported, "De-icing fluid detected by Westchester County in the Rye Lake section of New York City's Kensico Reservoir does not impact New York City's water supply system and is not hazardous to human health."
"The de-icing fluid, propylene glycol, which emanated from the Westchester County Airport, is the most commonly used de-icing compound and is also used as a food additive."
Another article on de-icing reports, "Chemicals, too, can keep wings ice-free in flight. A system called weeping wings, which is used on some smaller planes, lets the deicing fluid ethylene glycol ooze out of tiny holes and wash over the leading edge of wings."
http://www.chemistry.org/portal/a/c/s/1/feature_tea.html?id=c373e9f9697bff5d8f6a4fd8fe800100
I'm wondering if a plane with a "weeping wings" system was flying over the area and when the de-icer dripped off near the engines it created the smell. Just a theory by someone who never took chemistry :crazy: