Louisvillians who live near the JBS Swift meat-packing plant in Butchertown are advised to stay indoors following an ammonia leak."The sirens sounded," says a MetroSafe official. "If you can hear the sirens, you should stay inside."One building at the plant was evacuated shortly after 11:30 this morning. Emergency officials have not detected any leak outside of the building, but assessments continue.One patient has been taken to the hospital, according to MetroSafe, though no details about the injury available at this time.