Rainwater left untreated in cooling towers atop city-owned Harlem Hospital fueled the Big Apple’s deadliest Legionnaire’s disease outbreak in a decade, the Rev. Al Sharpton charged Tuesday.

A sixth person has died in a Harlem Legionnaires’ disease outbreak, health officials said Thursday. The city’s Department of Health and Mental Hygiene said there have now been 111 confirmed cases of the disease — and that seven people are currently hospitalized. None of the dead have been identified. A fifth person died earlier this week.

The Legionnaires' disease outbreak in Harlem has been traced to 12 cooling towers, including several at city-run buildings, officials said.

One particularly nasty bacteria-borne illness is currently spreading in New York City using those enormous cooling units as its vector: Legionnaire’s disease. The bacterial pneumonia, which usually recurs each summer in the US’s largest city, has sickened more than 100 people and killed five in a growing outbreak.