NEW YORK − Air conditioning has been a lifesaver in recent weeks for broad swaths of Americans left sweating ‒ and worse ‒ from scorching temperatures. But in parts of upper Manhattan, the quest for cool air has led to disease and death.

Deep inside the cooling towers of nearly a dozen apartment buildings, bacteria have taken advantage of poor maintenance to flourish and expand. As large air conditioning systems blew cool air into apartments, the bacteria hitched rides on the warm air they spewed out, in the other direction, into the Harlem skyline.

Since July 25, at least 67 people in five zip codes have inhaled that bacteria, and developed what's called Legionnaires' disease. Twenty-four were hospitalized and three have died.

It's already the largest outbreak in New York City in a decade, and health officials expect the number of people infected to rise.

City workers have already sampled all cooling towers in the five affected ZIP codes and treated the contaminated ones, Mayor Eric Adams said in a video update.