CONTRA COSTA Health officials confirmed Monday the since-closed Zen Day Spa in Richmond was the source of the Legionnaires’ disease that killed two people earlier this month. 

The health agency also said on Monday it has declared the spa a public nuisance and ordered the owners to professionally clean the space and dispose of the hot tub where the infections likely occurred within 30 days. 

Laboratory tests of water and swab samples collected from the spa contained high levels of legionella bacteria, health officials said.

The department began its investigation of the spa, at 12230 San Pablo Ave., on Aug. 4, after area hospitals reported two deaths from Legionnaires’ disease. Both people visited the business before becoming ill. 

The business voluntarily closed the next day. The health department said it has contacted more than 30 of the spa’s recent customers, as well as people in the area recently coming down with Legionnaires’ disease, reported through community health care providers.

Two other people who visited the business were confirmed to have had Legionnaires’ disease. 

(L-R) Contra Costa County Deputy Health Officer Dr. Meera Sreenivasan and Contra Costa County Supervisor John Gioia in front of Zen Day Spa in Richmond, Calif., on Aug. 7, 2023. Two spa patrons died of Legionnaires’ disease after recent visits. (Supervisor John Gioia via Bay City News)

The business may not reopen until re-inspected by the health department, which said the spa didn’t have the required permit to operate, nor was it ever inspected by the department. 

“Most public pools and spas have to have both disinfection and recirculation equipment,” said Kristian Lucas, Contra Costa Health’s assistant director of environmental health programs, during a press briefing Monday. “It was a residential unit and it didn’t have some of the systems like a disinfection system.”  

Legionnaires’ disease can cause serious pneumonia, according to the health department. While legionella bacteria naturally live in fresh water, health concerns can arise in hot tubs and pools where the bacteria can grow if the water is not maintained properly. 

People can become infected after breathing mist containing the bacteria. The disease does not spread from person to person. 

“Proper maintenance of hot tubs and pools is becoming increasingly important, both for businesses and private citizens who own tubs, as we continue to experience climate change,” said Dr. Ori Tzvieli, Contra Costa County health officer, in a statement. “Higher temperatures make growth of legionella and bacteria more likely, and more prolific, in water that is not properly treated.” 

Lucas said Contra Costa Health will recover the costs associated with its abatement effort from the spa owners and refer the case to the Contra Costa District Attorney’s Office for possible prosecution.