Duke Energy has turned to a high-powered corporate law firm to conduct an internal review of the power company's hiring of Indiana utilities regulator Scott Storms to work for Duke's legal division.

The hiring of Gibson, Dunn & Crutcher indicates the escalating ethics flap in Indiana risks broader legal exposure for the Charlotte-based power company and its top executives. Duke has utility operations in five states, including Indiana.

The ethics scandal has already resulted in the launching of a state investigation by the Indiana Inspector General, who is looking to see if any state laws were broken. The state has reopened all regulatory rulings in Indiana concerning Duke in which Storms presided.