Legionella outbreaks have been rare in Multnomah County and Legionnaires’ Disease is not known to spread from person-to-person.
But for people at increased risk, the bacteria can lead to severe pneumonia.
The Health Department notified more than 100 residents at Rosemont Court of concerns about the water system after multiple people became ill with pneumonia.
Multnomah County Health Officer Dr. Jennifer Vines says four people were hospitalized, one person has died.
The Communicable Disease investigations team says all signs point to the buildings water system.
The Multnomah County Emergency response team is offering temporary housing at local motels. Twenty people chose to leave Monday night with others willing to temporarily relocate today. The County also had meals delivered.