Belo-owned KHOU-TV Houston continues to rack up awards for its investigative work on the Firestone tire story, credited with prompting Congressional and other investigations and the recall of more than 6 million potentially dangerous tires. Last week, the story won a regional Edward R. Murrow Award from the Radio-Television News Directors Association and a George Polk Award. Earlier this month, it won an award for Journalistic Excellence from the Scripps-Howard Foundation. It also won an Emmy, a duPont-Columbia University Award and a National Headliner Award. The big Murrow winners were Fox-owned WTTG(TV) Washington, which garnered seven regional Murrows, and KVUE-TV Austin, Texas, and WNDU-TV South Bend, Ind., with six each.