I don't drive my minivan all that often, but when I do it's usually for longish trips in areas where there isn't a gas station at every corner; so I cram as much fuel into the tank I can.

I had no idea that topping off was not only bad for my wallet, but also for the environment.

On the cost side of things, it seems that many gas pumps are equipped with features that suck back gas vapors into the station's storage tanks to prevent vapors from escaping. Any additional gas I try to pump in might just be fed back into those tanks.

My habit is also bad news for the planet -  gas tanks require a bit of room to allow the fuel to expand. By topping off, the excess gas may evaporate into the van's vapor collection system, become fouled and cause higher emissions.

These points and a couple of other negatives of topping off when refueling that I haven't mentioned were taken from the U.S. Environmental Protection Agency web site.

All common sense sort of stuff I guess, but isn't that a lot of what green living is about? We tend to focus on the big things that may be unnattainable and become discouraged where there's so many little things we can do that can collectively make a difference in the impact we have on Earth.

Pick up some more simple gas saving tips.