By the mid-1970s, the environmental movement was gaining headway in North America, and concern about pollution from the steel mill and coke ovens was rising. Environmental activists would subsequently uncover documents showing that the government was aware of environmental problems caused by the steel plant and coke ovens as early as 1972. In 1980, scientists from the Department of Fisheries and Oceans discovered polycyclic aromatic hydrocarbons (PAHs), a family of chemicals produced by incomplete combustion of organic material, in lobster caught in Sydney Harbour near Muggah Creek. These same toxic chemicals were found in the homes of nearby residents. They ordered the South Arm of the harbour closed to lobster fishing, and figured the Tar Ponds as the likely source of contamination.
