LINCOLN, Neb. (AP) – A Canadian pipeline operator that wants to run a controversial oil line through Nebraska is proposing new safeguards it says would limit the effects of a spill. But in a letter to Speaker of the Legislature Mike Flood, TransCanada executive Alex Pourbaix maintains that the company cannot reroute the proposed Keystone XL away from the Nebraska Sandhills, as critics and some lawmakers want. Pourbaix says that, in addition to its existing commitments to clean up a spill, TransCanada is willing to provide a $100 million performance bond payable to Nebraska if the company fails to clean up a spill in the Sandhills. Pourbaix met with Flood and several other lawmakers last week to address concerns about a pipeline spill near the Ogallala aquifer, which supplies drinking and irrigation water.