In the coming months, hundreds of pieces of steel pipe will be strung together in Missouri as part of Enbridge Energy Co.’s Flanagan South Pipeline, a new 589-mile artery that will transport heavy Canadian oil through the nation’s midsection. The 36-inch diameter Flanagan South Pipeline will run diagonally across 11 Missouri counties from just north of Hannibal to Bates County, about an hour south of Kansas City. But just over a week ago, the Sierra Club sued the Corps of Engineers in federal court in Washington for failing to provide access to application materials provided by Enbridge under the Freedom of Information Act. The St. Louis-based Missouri Coalition for the Environment filed a similar lawsuit a day later. On Friday, the Sierra Club and National Wildlife Federation filed an amended lawsuit challenging the project’s environmental impact.