Gotta hate it when this kind of thing happens—as it all too often does. This is an on-going story and, as always in such cases, there's way more we don't know than that we do. But here's what we do know so far.There was a large explosion and fire at the Geismar, La., Williams Olefins chemical plant this morning. Dozens were injured and officials ordered residents withing 2 miles of the plant to remain indoors. The blast hit at 8:37 a.m. at the plant along the Mississippi River just south of Baton Rouge and about 60 miles up river from New Orleans, parent group Williams Cos. said in a statement.For the rest of the story, go here.