CHICAGO (CBS) — Three schools in Elgin and the District U-46 central offices have been evacuated, after air quality tests found higher than normal levels of Legionella bacteria in their cooling towers.

In a message on the district’s Facebook page, Elgin School District U-46 CEO Tony Sanders said the elevated levels of Legionella bacteria were found during air quality testing of cooling towers at Eastview Middle School, Larkin High School, and the Educational Services Center — which houses Gifford Street middle and high schools, the Central Schools Program, and the district’s central offices.

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The schools were closed immediately, and students were taken to other facilities, or sent home.

“We are keeping these three buildings closed in an abundance of caution,” said CEO Tony Sanders. “We have absolutely no evidence that our students have been exposed to anything harmful. We expect to re-open these sites Friday after we repeat the cleaning process.”

The central office also has been closed, and emergency operations were being conducted at the district’s plant operations facility off Shales Parkway.

Concerned parents rushed to the schools to pick up their kids after the evacuation.

“I was scared,” said parent Brenda Vinson. “I am a nurse and I know what Legionnaires disease is,” said parent Brenda Vinson.

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“I think it was just a precaution,” said parent Jaime Hanrahan. “I can appreciate them being cautious for the safety of the kids.”

At Eastview Middle School, the presence of Legionella bacteria exceeded one thousand parts per million, the same was true at Gifford Street and central administration; Larkin High was just below that level, which is when federal guidelines call for emergency action.

In addition to cleaning all 19 systems in the district, the schools also being exposed to halogen, lighting which officials say helps kill the bacteria. The district received the results Wednesday morning, and by 10:30 a.m., parents were notified though Facebook, phone, and email blasts.

Students said, for the most part, the evacuations were orderly.

“A lot of people were calm some people were freaking out but it was ok,” said 12-year-old Emily Hanrahan.

Potentially fatal Legionnaires’ disease is spread by breathing in a mist or vapor containing the bacteria. Administrators say the likelihood of that type of exposure related to these findings is extremely minimal.

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“This was just in our water cooling towers, this is not in our plumbing, it is not any other place,” said Sanders.