The New York Times has a great article on the ecological trouble caused from : de-icing by state highwar departments "creating an environmental problem that lasts far beyond winter." Its an intersting read, now that winter is finally wanning and we can witness firsthand the results of our activities.
I used to work on this issue quite a lot and actually represented a comapny with a great ecologically sound product that was wholly biodegradable (it was essentially made from mash, the spent grain byproduct of the brewing industry) and worked better than salt. We even created a market for them by getting congress to ensure millions upon millions in subsidies to states that purchased their product.
However, no amount of free money and good product can overcome bad management and as a result of mismanagement, the company squandered a fortune and barely exists anymore. Seems the Gun Guy has touched upon this subject in the past.