About 430 oil and gas pipelines failed recent leak-detection tests, according to the Colorado Oil and Gas Conservation Commission. That’s about-one third of 1 percent of all the lines tested. Gov. John Hickenlooper ordered the tests after a home explosion in Firestone killed two men earlier this year. He said in a statement that while the number is relatively small, each failure requires attention. Officials are now working with the companies to make sure every line gets repaired.