Authorities say that state Sen. Greg Barkus was driving his boat at least 40 mph when it crashed into a rocky cliff on Flathead Lake last week, injuring U.S. Rep. Denny Rehberg and three other passengers. Flathead County Attorney Ed Corrigan also says he is awaiting results of a test for Barkus's blood-alcohol level from the state crime lab in Missoula. Corrigan has said that he is weighing felony charges in the case. Most seriously injured was Rehberg’s state director Dustin Frost, who has a Skull fracture and a brain injury. Corrigan says Frost's family remains optimistic that he'll recover. Rehberg suffered a broken ankle that required surgery. The boat passengers had been at a dinner on Aug. 27 and were using the boat to get back to their resort on the other side of the lake when they crashed after 10 p.m.