New York City rewrote its cooling tower rules in response to a deadly Legionnaires' outbreak, tripled how often building owners must test for the bacteria, and put the new regime into effect on May 8. Eight weeks later, a second lethal cluster began on the Upper East Side.
The NYC Health Department reported 89 people diagnosed as of its July 26 update, with five deaths confirmed as of July 21. It has tested 183 cooling towers at 160 buildings in the affected ZIP codes. Fifty-seven towers at 56 buildings returned culture-positive results confirming live Legionella, and all have been cleaned and disinfected. Seventy-nine towers tested culture negative, and the rest are pending.
