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 as a result of the Legionnaires’ disease outbreak in Harlem, which has sickened more than 100, health officials said.

A fifth New Yorker has died in the Legionnaires’ disease outbreak in Harlem, city health officials said.

A fifth person has been killed by the Legionnaire’s disease outbreak ripping through Harlem, which has also sickened more than 100 others, health officials announced.

Ben Crump and Rev. Al Sharpton will announce a lawsuit against a construction company accused of causing the outbreak.

Legionnaires’ disease is a rare condition, and incidence is hard to estimate because diagnosis requires a suspicion of disease and ordering of the tests needed for confirmation, said Krishna Thavarajah, MD, a pulmonologist and director of the Interstitial Lung Disease Program at Henry Ford Hospital, Detroit, in an interview.

At a town hall on Thursday, Harlem residents raised questions and concerns about the Legionnaires’ disease outbreak that has resulted in nearly 100 cases and four deaths since last month.