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 fifth person has died in connection with a Legionnaires’ disease outbreak in New York City. The outbreak in Central Harlem has sickened dozens since it began in late July and the latest death was announced Monday night.

Four people have died as a result of a Legionnaires’ disease outbreak in Harlem that has sickened nearly 100 people, and officials revealed the cooling towers that tested positive for the bacteria that causes the illness — some of which are at properties owned by New York City,