Disneyland cooling tower was likely source of all 22 Legionnaires’ cases, official testifies

Guests along Main Street in Disneyland in 2017. The theme park is appealing a Cal-OSHA citation and fine for failing to properly clean cooling equipment linked to last year's Legionnaires' disease outbreak.
Guests along Main Street in Disneyland in 2017. The theme park is appealing a Cal-OSHA citation and fine for failing to properly clean cooling equipment linked to last year’s Legionnaires’ disease outbreak.
(Gary Coronado / Los Angeles Times)

A cooling tower at Disneyland was the likely source for all 22 cases in a Legionnaires’ disease outbreak last year near the theme park, an Orange County health official testified Tuesday.

Most of those who fell ill visited the park in the fall of 2017. Disneyland has denied it was the source, pointing to three infected people who had been in Anaheim but not at Disneyland. One of them died.

Dr. Matthew Zahn, medical director for epidemiology at the Orange County Health Care Agency, told an appeals board judge at the California Occupational Safety and Health Administration that those three people were in nursing homes in Anaheim. He said health workers visited the nursing homes and determined there were no likely sources of the Legionella bacteria there.


Tests around the time of the outbreak showed high levels of Legionella bacteria in two of Disneyland’s cooling towers, which likely spread contaminated droplets to people in the park, Zahn said. The medical director said he concluded the three nursing home patients were probably sickened by Disneyland as well, because water infected with Legionella bacteria “can spread two to four miles.”

Zahn pointed out that cooling towers — part of an air-conditioning system that releases mist — are the most common source of Legionnaires’ outbreaks.

Disneyland cooling tower #4 had very high levels of Legionella bacteria when people began to fall sick, Zahn said. Once it was sanitized, Legionnaires’ infections appeared to cease, he added.

“Most likely those cases were related to a common exposure,” Zahn said. “Cooling tower #4 was the most likely source of exposure.”

The health agency has never formally identified a cause of the outbreak. Upon questioning by Disneyland’s lawyers, Zahn said he could not be 100% certain that Disneyland was the source of all of the cases without additional testing.

He also said the county’s environmental health workers could not identify a source of the outbreak when they examined the park’s water sources in October last year.


“They did not find an obvious — on their pass through — source,” Zahn said.

Earlier this year, Disneyland spokeswoman Suzi Brown said in a statement: “We strongly object to Cal-OSHA’s allegation that our cooling towers caused any illness, since the source of the outbreak has never been scientifically determined.”

In March, the Cal-OSHA cited and fined Disneyland $33,000 for failing to properly clean cooling equipment linked to the outbreak and other related violations.

The agency investigates only hazards that endanger workers, so its findings focus on how three Disneyland employees were infected and does not address the 19 non-employees sickened.

Disneyland is appealing the citation at a two-day hearing in West Covina that began Tuesday. Christopher Merrill, the Cal-OSHA administrative law judge, will rule within 60 days.

Zahn was a witness called by lawyers for Cal-OSHA. Testimony by the agency’s witnesses will continue Wednesday. Disneyland is expected not to call any witnesses, Merrill said.

Cal-OSHA lawyers also called Christopher Casteel, who conducted the investigation into Disneyland’s violations.

Casteel, associate safety engineer with the agency’s Department of Industrial Relations, said cleaning records showed that Disneyland did not follow proper guidelines to disinfect its cooling towers, thereby allowing high levels of bacteria to grow in the towers and spread in the park.

Orange County health officials never formally identified the cooling towers as the source of the outbreak, and Disneyland officials have said that the test results don’t definitively prove that the towers were to blame.

Disneyland’s cooling towers have been free of Legionella since November 2017, and there is currently no risk to the public, Orange County health officials said.

Meanwhile, a young girl who was diagnosed with Legionnaires’ after visiting Disneyland last fall filed a suit against the theme park last week in Los Angeles County Superior Court. The girl went to the theme park in mid-October last year to celebrate her mother’s birthday and two weeks later developed a persistent cough, according to the lawsuit.

“The facts don’t support these claims and the lawsuit has no merit,” Disney’s Brown said Tuesday.

The girl visited the theme park on Oct. 13, 2017, but the last person who developed Legionnaires’ as part of this outbreak visited the park on Oct. 3, according to Zahn’s testimony Tuesday.

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