An outbreak of Legionnaire’s disease in Orange County may be linked to two cooling towers at Disneyland. County health officials say 12 people contracted the lung disease, including one Disneyland employee and nine who visited the park, with one person who had not visited the park ultimately dying.

Nine of the afflicted had visited the park in September, with the others living or traveling in Anaheim. Two cooling towers that were in an area inaccessible to theme park guests have since been disinfected and shut down until health officials can certify them as disinfected.

Legionnaires was first identified in 1976 when an outbreak occurred at an American Legion convention in Philadelphia. About 182 attendees were sickened, with 29 dying from the severe lung infection. The outbreak was traced to the convention hotel’s air conditioning system, and Legionnaire’s disease has since been sourced to contaminated water or mist.

The disease is treatable, but roughly one in 10 people who contract the disease die from it, with people over 50 with weakened immune systems or chronic lung disease most at risk. The person who died from the Disneyland problem had underlying health issues, according to health officials.

“On Oct. 27, we learned from the Orange County Health Care Agency of increased Legionnaires’ disease cases in Anaheim,” said a statement from Dr. Pamela Hymel, chief medical officer for Walt Disney Parks and Resorts. “We conducted a review and learned that two cooling towers had elevated levels of Legionella bacteria. These towers were treated with chemicals that destroy the bacteria and are currently shut down.”

The Orange County Health Care Agency said 12 people aged 52 to 94 contracted the disease. Of that total, nine had visited the park in September, and the remainder lived or traveled in Anaheim. Ten were hospitalized and one person “with additional health issues” died, according to a report in the Los Angeles Times. The health agency said there is no ongoing risk to the public and no other cases have been reported, although they cautioned public health officials to be aware of the situation.

The towers traced to the outbreak were located near the New Orleans Square Train Station, both towers more than 100 feet from public areas. The U.S. Centers for Disease Control and Prevention notified county officials of the outbreak among people who had traveled to Orange County. The county contacted Disney after it discovered several had gone to the park.