A Legionnaires’ disease outbreak in Harlem has claimed a fourth life, with nearly 100 confirmed cases and more than a dozen people still hospitalized. For the first time, city officials have identified 12 cooling towers that tested positive for Legionella bacteria — including four city-owned buildings such as Harlem Hospital.

Some in the area say they were unaware of the outbreak of Legionnaires' disease, let alone the location of problem sites.