CNN reports on container with ammonium nitrate left on street that could have done some real damage. Experts trying to decide if meant to go off, or a dry run for something bigger. City on alert. This happened almost two weeks ago details just emerging now. "Initial tests showed the device contained ammonium nitrate, the same volatile substance that sparked a massive explosion last month at a fertilizer distribution plant 110 miles north in West, Texas, said Austin fire Lt. Randy Elmore. He called the apparatus 'a legit system.'"