Former Idaho Gov. and U.S. Interior Secretary Dirk Kempthorne has died at age 74. His family said in a written statement that he died Friday evening in Boise. No cause was given, but he had been diagnosed with colon cancer last year. Kempthorne, a Republican, was elected mayor of Boise at age 34 and served seven years before serving one term in the U.S. Senate and then as governor until 2006. That's when President George W. Bush appointed him Interior secretary. Kempthorne was responsible for the polar bear being listed as a threatened species in 2008, though environmentalists often found him too accommodating of the oil and gas industry.