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 Legionnaires' disease outbreak in New York's Central Harlem has now caused four deaths and sickened 101 people, New York City health officials confirmed.

Two construction workers who claim they contracted Legionnaires' disease while working at or near Harlem Hospital Center are suing contractors they allege failed to safeguard water cooling towers at the building against contamination by the bacteria that causes the illness.

A law firm filed a lawsuit Aug. 20 against a New York City hospital’s construction company, alleging the company failed to treat bacteria-infected water in its cooling towers, leading to a Legionnaires’ disease outbreak.

Lawsuit filed after a deadly Legionnaires' outbreak in Harlem, alleging negligence by construction firms and NYC.