Sarnia is home to more than 60 refineries and chemical plants that produce gasoline, synthetic rubbers, and other materials that the world's industries require to create the commercial products we know and love. The city's most prominent and profitable attraction is an area about the size of 100 city blocks known as the Chemical Valley, where 40 percent of Canada's chemical industry can be found packed together like a noxious megalopolis.
According to a 2011 report by the World Health Organization, Sarnia's air is the most polluted air in Canada. There are more toxic air pollutants billowing out of smokestacks here than in all of the provinces of New Brunswick or Manitoba.
Canada's Toxic Chemical Valley - Environment pollution documentary