Road salt is set to become the latest addition to Canada’s list of extremely toxic substances. Environment Minister David Anderson is recommending the addition based on research showing that the tons of salt used to de-ice the country’s highways each winter are polluting groundwater and killing vegetation. Environmentalists lauded the move, which is expected to lead to tighter controls on the use of road salt. Not surprisingly, folks at the Salt Institute of Canada, the industry’s trade group, weren’t excited about the possibility of having to chain up their tires.