(CNN) After six passengers traveling through a Cleveland airport this week became sick, officials shut down water fountains and brought in an independent company to test the water.

Thursday, the city said the water at Cleveland Hopkins International Airport is safe to drink.

"Results show that the airport's drinking fountains and water supply met or exceeded the standards set for drinking water and did not contain bacteria or harmful metal levels," the city said.

Several water fountains were shut down Tuesday after passengers aboard a Frontier Airlines flight became sick, airport officials said.

At least six passengers who traveled on Tampa-bound Frontier Airlines Flight 1397 on Tuesday fell ill after leaving Cleveland.

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