Boston Logan Airport deicing fluid transition

Historical transition from polyethylene glycol (toxic — metabolizes to methanol, causes blindness, EPA-controlled with collection dams) to polypropylene glycol (food-additive grade, metabolizes to ethanol, used at the gate now). Used as biochemistry digression off the carburetor-icing teaching beat.

Someone told me that the Canadian aviation authority — and I have since gotten a copy of this report — ran tests to see if putting Teflon on the surface of the carburetor would prevent ice from building up. They were also interested in deicing of airplane wings. If you've ever taken off in the winter at Logan, they have to spray your aircraft with deicing solution. Do you know what that solution is? Usually it's polyethylene glycol. However, I think they may have switched recently to polypropylene glycol. One of them is toxic, and they have to take the planes over to a little part of the area, because they now have a little dam around there so they can collect all the polyethylene glycol — the EPA gets very upset if you just let it get into the ocean. But now I've noticed they've been deicing just back from the gate, which means they've switched to polypropylene glycol, which is a food additive.