EMPORIA, Kan. (AP) — Seven people have been released from an Emporia hospital after an ammonia leak at the city's Tyson Foods plant. KVOE-AM reports that emergency workers were sent to the plant Thursday morning. Officials said the level of ammonia that was leaking was well below what's considered lethal. Tyson spokesman Gary Mickelson says the leak temporarily disrupted production in part of the processing plant before it was found and stopped. About six weeks ago, Tyson Foods agreed to pay a nearly $4 million civil penalty to settle alleged violations of the Clean Air Act, largely because of ammonia issues. And in April 2009, an accidental release left one person injured.