EcoWatch: A scary thing happened on Halloween near Hinton, Alberta. Canada had what may be the largest coal slurry spill in its history when a dam failed at the Obed Mountain coal mine and 264 million gallons (1 billion litres) of waste water contaminated at least 25 kilometers of the Athabasca river. Ten municipalities located downstream of the spill were warned not to withdraw raw drinking water from the Athabasca river until it was deemed safe. Residents were also warned not to let their animals drink water...