WASHINGTON, D.C. — U.S. officials knew of the potential for a catastrophic "blowout" of toxic wastewater from an inactive gold mine, yet appeared to have only a cursory plan to deal with such an event when government contractors triggered a 3-million-gallon spill, according to internal documents released by the Environmental Protection Agency. The EPA released the documents late Friday following weeks of prodding from The Associated Press and other media organizations. The Aug.