The head of a suburban Chicago school district that evacuated because Legionella was found says there is a lack of public health guidance for schools to help deal with the bacteria. Elgin Area School District CEO Tony Sanders says he didn't receive guidance from state or federal agencies on when it was safe to reopen schools and it ``was incredibly frustrating.'' The district evacuated and shut three schools for three days last month after high levels of Legionella were found in water cooling towers. Illinois public health officials say there is no safe level of Legionella in a water system and the department would only become involved if there are human cases. District officials say they finally received advice from Advocate Sherman Hospital in Elgin.