The head of an Elgin school district that closed three of its schools for three days because Legionella was found said there is a lack of public health guidance about the bacteria for schools, a suburban newspaper is reporting.

Elgin Area School District U-46 CEO Tony Sanders said he didn’t receive guidance from state or federal agencies about when it was safe to reopen Eastview Middle School in Bartlett, Larkin High School in Elgin and the district’s Educational Services Center in Elgin last month. The closings came after high levels of Legionella were found in water cooling towers.

“It was incredibly frustrating,” Sanders told the (Arlington Heights) Daily Herald. He said he still doesn’t know if closing the schools was necessary.

Illinois had about 1,640 sicknesses from Legionella bacteria between 2005 and 2014. Two of those cases involved patients who were younger than 18.

Melaney Arnold, spokeswoman for the Illinois Department of Public Health said there is no safe level of Legionella in a water system and the department would only become involved if there are human cases.

The Centers for Disease Control and Prevention recommends superheating or hyper-chlorinating water systems.

The Occupational Safety and Health Administration also recommends immediate cleaning and says employers should “take prompt steps to prevent employee exposure.” However an OSHA representative said public school district aren’t under the agency’s jurisdiction.

The schools drained and flushed all 19 cooling towers with four times the amount of disinfectants, officials said.

District officials ultimately received advice from Advocate Sherman Hospital in Elgin, receiving the OK to reopen from Robert Tiballi, who is head of infection control at the hospital.

“The decision to reopen the buildings was based on the statistical likelihood that we would have achieved 100 percent reduction in the colony counts,” Tiballi said.

Sanders said the school will be better prepared if high levels of Legionella are found again.

“We will have a plan in place so that this does not happen again,” he said.