A person in their 50s has died and twelve others were hospitalized in California with Legionnaires’ disease.

Authorities say they have been working to find the source of the disease. High levels of Legionella bacteria were traced to a cooling tower at Embassy Suites Napa Valley, according to health officials.

Napa County says the cooling tower has been taken offline.

“Our joint investigation team continues to work with Embassy Suites staff to remediate the source of exposure,” said Dr. Karen Relucio, Napa County Health Officer. “Finding Legionella in one water sample is an important piece of the puzzle, but we must continue to investigate other cooling towers and water sources in the outbreak area, as it is common to find more than one source.”

Officials say the person who died had high risk factors for severe disease.

"Although Legionnaires’ disease is a rare infection, this is a reminder that the bacteria that cause it are common in nature and can be found in man-made water systems," said Dr. Relucio. "This means it’s very important for owners and managers of water systems that can create aerosols to take steps to prevent Legionella from growing and spreading in water systems."