Public health officials have traced a Legionnaires’ Disease outbreak to a hot tub in an L.A. Fitness facility in Niles, Illinois.

Two people diagnosed with bacterial pneumonia reported using the pool, steam room, hot tub, and showers at the gym when they contracted the disease at the end of April.

The gym was notified of the cases on May 5 and closed its pool, spa, showers, and steam room at that time while the Illinois Department of Public Health (IDPH) began its investigation of the facility. On May 16, testing confirmed that samples collected from the facility’s hot tub contained legionella pneumophila S2-14, the bacterium that causes Legionnaires’ Disease.

L.A. Fitness employees then began treating the hot tub to remove any trace of the bacteria, and the hot tub and surrounding areas remained closed until additional testing could confirm its absence.

A member of the gym, who did not want to be identified, said he felt more should be done to notify members.

“Pneumonia is serious anytime, but the fact of the matter is, according to what I’ve read, people who are over 50 are at risk,” he said. “This space is at risk of transmitting it and probably 20 to 30% of the people in the morning when we go to the gym are over the age of 50.”

While not contagious, Legionnaires’ Disease is spread by breathing aerosolized water droplets contaminated with the bacteria, and although it is treatable, it can be deadly.

“I would like them to have a plan in place for this type of, you know, infection being transmitted in their space,” the gym member said. “And I hope the two gentlemen who got sick, you know, take the time to let them know how disappointed they are.”

Legionella bacteria is readily killed with chlorine but can proliferate in a biofilm matrix within plumbing, where a mixture of dead skin cells and organic matter provides an ideal environment for bacteria to thrive, where it is protected from regular chlorine dosing.