Crude bomb left on Oklahoma gas line, FBI says
"A law enforcement official who spoke on condition of anonymity told CNN the device was made up of black powder, propane and a timing device."
http://www.cnn.com/2011/CRIME/08/10/oklahoma.pipe.bomb/
This is an accurate report. The device was disrupted, but did not detonate when this occurred. That does not mean it wasn't a viable device, which will have to be ascertained by a lab analysis. What we do know is that the required components for a viable IED were present.