Canadian Consulting Engineer

Legionnaires’ outbreak in Bronx prompts city-wide disinfection

August 18, 2015

New York City council adopts part of new ASHRAE standard in legislation to deal with the deadly problem.

New York City is suffering from the worst Legionnaires’ outbreak in its history, with 12 people reported dead, and 120 people infected this month.

The outbreak is concentrated in the South Bronx, where 20 cooling towers out of 135 tested have been found to be harbouring the Legionella bacteria. The bacteria is spread through building air-conditioning systems.

On August 6, New York City Council passed legislation requiring all building cooling towers in the city to be tested and disinfected within two weeks of receiving a letter.

Since then the limited number of companies who specialize in the work have been struggling to keep up. Anthony DeVito of Chemical Specifics told the New York Times that the disinfection measures that many building owners were using were only short term solutions: “only a thorough cleaning of a tower would address hard-to-reach bacteria in the nooks and crannies or in sludge accumulated at the bottom.”


Two months previously ASHRAE had only just published a new Legionella standard, ANSI/ASHRAE 188-2015, “Legionellosis: Risk Management for Building Water Systems.” The city’s new legislation incorporates Section 7 of the standard, which lists the steps to be taken for system start-ups and shut-downs, maintenance, water treatment and disinfection.

Michael Patton, the head of the ASHRAE committee that wrote the new standard, testified before the city council that other sections of the standard would also help to reduce risks.

ASHRAE President David Underwood, said he hoped the standard would be adopted by other cities: “Standard 188 was published just two short months ago. Although the circumstances surrounding its use are tragic, ASHRAE is grateful that the standard is available to set requirements to manage risk of this bacteria. We are hopeful other governments will follow the lead of the New York City Council to help safeguard public health.

To read an August 16 article in the New York Times, click here.

To read the ASHRAE press release, click here.


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