The blast happened inside a shed at a building on Olinville Avenue just after 10 Tuesday morning.
Investigators said Joseph Mclenden, 38, was attempting to clean the tank when it exploded in his face.
He was rushed to Jacobi Medical Center, where he died. The cause of the explosion was under investigation, but officials said it was considered accidental.
Residents said they felt the blast several blocks away.
No other injuries were reported.