Health officials have determined that a water filter removed too much chlorine, possibly allowing the spread of Legionnaires' disease, which is suspected of sickening at least two guests since October at the luxury EPIC Hotel in Miami.

Based on an initial investigation, it appears that the hotel installed a special filtration system to enhance the quality of drinking water. According to an article in the New York Times, Samir Elmir, director of the county’s environmental health and engineering division, said this system used a common “activated carbon” mechanism that according to tests was powerful enough to remove chlorine from city-supplied water – a move that encouraged bacterial growth. Health officials are now working with hotel staff to figure out what went wrong.

“We're looking at hot and cold showers, the cooling tower, the plumbing system. Their levels [of chlorine] were significantly below what is provided by county water,'' Elmir said in a Miami Herald story.

The EPIC is currently closed for inspection and disinfection, which includes adjusting the hotel’s water system so that the incoming city water bypasses the filter. Health officials then plan to triple the chlorine levels temporarily to halt bacterial growth.

About 300 guests were relocated to other nearby hotels to prevent further illnesses; however doctors with the Miami-Dade County Health Department said there is no cause for widespread alarm. Legionella bacterium, the cause of Legionnaires’ disease, a form of pneumonia, is not spread from person to person. According to the World Health Organization (WHO), the death rate for people with healthy immune systems is about 10 percent to 15 percent.

The U.S. Centers for Disease Control and Prevention estimates that between 8,000 and 18,000 patients are hospitalized each year with the disease. The EPIC Hotel cases were the first in Miami-Dade County since 2007.

Whereas some people believe adding chlorine to public drinking water does more harm than good, the situation in Miami underscores the absolutely essential role that chlorine plays in minimizing the threat of Legionnaires’ disease and many other waterborne diseases in the U.S. You can learn more about the importance of chlorine and safe drinking water at www.waterandhealth.org.

(Chris J. Wiant, M.P.H., Ph.D., is president and CEO of the Caring for Colorado Foundation. He is also chair of the Water Quality & Health Council).

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