Once upon a time, the Environmental Protection Agency decided to study 128,000 schools around the country, in order to determine where children are being exposed to the most toxins. When EPA officials got their test results back, they ranked the schools according to the nastiest air. And three schools in West Berkeley made the list of the most toxic environments in the country: the Black Pine Circle school, the Nia House Learning Center, and the Via Center. What could be gunking up the air and turning the kiddies' lungs into little bags of cancer bombs? According to the Trib, that would be Pacific Steel Casting, the factory a mile north near Gilman Street. Seems a good chunk of manganese gets spewed out of the foundry and drifts south toward the four-square games.